WARNING Research and Development

Arthur, A. T., G. M. Cox, N. R. Kuhnert, D. L. Slayter, K. W. Howard, 2005: The National Basin Delineation Project. Bulletin of the American Meteorological Society, 86, 1443-1452.

Brown, R. A., J. M. Kurdzo, P. L. Heinselman, 2009: Progress report on evolutionary characteristics of a tornadic supercell thunderstorm: Comparisons of 1.0–min phased array radar and 4.2–min WSR–88D measurements. Preprints, 25th International Conference on Interactive Information and Processing Systems, Phoenix, AZ, USA, American Meteorological Society, 9B.3.

Brown, R. A., 2009: Considering the problem of having too many WSR–88D volume coverage patterns. Task 5, FY 2009 Memo. of Understanding between NWS Radar Operations Center and NSSL Final Report, 11 pp.

Brown, R. A., 2008: The forecaster’s dilemma: Which WSR–88D VCP to use. Task 5, FY 2008 Memo. of Understanding between NWS Radar Operations Center and NSSL, Final Report, 21 pp.

Brown, R. A., 2008: Statistics of WSR–88D velocity dealiasing errors categorized by VCP, 2005–2008. Task 9, FY 2008 Memo. of Understanding between NWS Radar Operations Center and NSSL, Final Report, 7 pp.

Brown, R. A., V. T. Wood, D. C. Dowell, 2008: Impact of a tornado’s low–reflectivity eye on distorting the associated peak Doppler velocity measurements: A simulation study. Preprints, 24th Conference on Severe Local Storms, Savannah, GA, USA, American Meteorological Society, P3.5.

Brown, R. A., T. A. Niziol, N. R. Donaldson, P. I. Joe, V. T. Wood, 2007: Improved Detection Using Negative Elevation Angles for Mountaintop WSR-88Ds. Part III: Simulations of Shallow Convective Activity Over and Around Lake Ontario. Weather and Forecasting, 22, 839-852.

During the winter, lake-effect snowstorms that form over Lake Ontario represent a significant weather hazard for the populace around the lake. These storms, which typically are only 2 km deep, frequently can produce narrow swaths (20–50 km wide) of heavy snowfall (2–5+ cm/hr) that extend 50–75 km inland over populated areas. Subtle changes in the low-altitude flow direction can make the difference between accumulations that last for 1–2 hr and accumulations that last 24 hr or more at a given location. Therefore, it is vital that radars surrounding the lake are able to detect the presence and strength of these shallow storms.
Starting in 2002, the Canadian operational radars on the northern side of the lake at King City, ON (WKR) and Franktown, ON (XFT) began using elevation angles as low as -0.1 deg and 0.0 deg, respectively, during the winter to more accurately estimate snowfall rates at the surface. Meanwhile, WSR-88D radars in New York State on the southern and eastern sides of the lake—Buffalo (KBUF), Binghamton (KBGM), and Montague (KTYX)—all operate at 0.5 deg and above. KTYX is located on a plateau that overlooks the lake from the east at a height of 0.5 km. With its upward-pointing radar beams, KTYX’s detection of shallow lake-effect snowstorms is limited to the eastern quarter of the lake and surrounding terrain.
The purpose of this paper is to show—through simulations—the dramatic increase in snowstorm coverage that would be possible if KTYX were able to scan downward toward the lake’s surface. Furthermore, if KBUF and KBGM were to scan as low as 0.2 deg, detection of at least the upper portions of lake-effect storms over Lake Ontario and all of the surrounding land area by the five radars would be complete. Over-lake coverage in the lower half (0-1 km) of the typical lake-effect snowstorm would increase from about 40% to about 85%, resulting in better estimates of snowfall rates in landfalling snowbands over a much broader area.

Brown, R. A., V. T. Wood, cited 2007: A Guide for Interpreting Doppler Velocity Patterns: Northern Hemisphere Edition, 2nd ed.. [Available online at ://http://www.nssl.noaa.gov/papers/dopplerguide/.]

Brown, R. A., R. M. Steadham, 2007: Developing site-specific scanning strategies for WSR-88Ds: Important considerations. Preprints, Annual Meeting, Reno, NV, USA, National Weather Association, 94-95.

Brown, R. A., 2007: Using mesocyclone signatures to compare techniques for creating 1.0 deg azimuthal WSR-88D data from 0.5 deg super-resolution data. Task 3, FY 2007 Memo. of Understanding between NWS Radar Operations Center and NSSL, Final Report, 16 pp.

Brown, R. A., V. T. Wood, 2007: Comparisons of switching from WSR-88D clear air mode to precipitation mode using the operational mode selection function (MSF) and a modified mode selection function (MMSF). Task 4, FY 2007 Memo. of Understanding between NWS Radar Operations Center and NSSL, Final Report, 9 pp.

Brown, R. A., T. A. Niziol, N. R. Donaldson, P. I. Joe, V. T. Wood, 2006: WSR-88D monitoring of shallow lake-effect snowstorms over and around Lake Ontario: Simulations of improvements using lower elevation angles. Preprints, 22nd Conference on Interactive Information Processing Systems, Atlanta, GA, USA, American Meteorological Society, CD-ROM, P2.7. [Available from Rodger A. Brown, National Severe Storms Laboratory, 120 David L. Boren Blvd., Norman, OK, USA, 73072.]

Winner, best poster presentation of conference.

Currently, National Weather Service (NWS) WSR-88D radars do not operate below +0.5 deg. Consequently, shallow lake-effect snowstorms over and around Lake Ontario pose a detection (and warning) challenge for the Buffalo, NY, NWS Forecast Office. Limited measurements in the lower portions of the storms preclude reliable quantitative precipitation estimation (QPE) in much of the coverage area.

This presentation will show how we use simulated scanning strategies to investigate how much detections and QPE would improve using lower elevation angles for the three closest New York State WSR-88Ds: Montague (KTYX), Buffalo (KBUF), and Binghamton (KBGM). Canadian radars at King City and Franktown on the north side of the lake—that operate as low as –0.1 and 0.0 deg, respectively—also are considered.

The Montague radar is located east of Lake Ontario on top of the Tug Hill Plateau 520 m above the lake. Using current scanning strategies, 2-km-deep snowstorms are detectable to a range of only 100 km from the radar (covering the eastern quarter of the lake). The Buffalo radar covers the western half of the lake. Being farther from the lake, the Binghamton radar covers snowstorms that extend southeastward from Lake Ontario.

Simulations show that, when the lowest elevation angle for KTYX is decreased to –0.4 deg, the range of detection of 2-km-deep snowstorms increases from 100 to 220 km. Lowering the lowest elevation angle for KBUF and KBGM to +0.2 deg increases the coverage area (2 km above the surface) by about 60%. Lowering the scanning strategies for these three radars and operating in conjunction with the Canadian radars, shallow lake-effect storms would be detected over the entire lake and surrounding coastal regions and reliable QPE information would be available over nearly the entire region.

Brown, R. A., V. T. Wood, D. C. Dowell, 2006: Interpretation of simulated WSR-88D Doppler velocity signatures of tornadoes associated with nonuniform reflectivities. Preprints, 23rd Conference on Severe Local Storms, St. Louis, MO, USA, Amer. Meteor. Soc., CD-ROM, P9.10.

Typically, when simulated Doppler velocity measurements are made across a tornado, one assumes that the associated reflectivity field is uniform. However, recent measurements made by mobile Doppler radars in the immediate vicinity of tornadoes reveal the presence of a low-reflectivity eye centered on the tornado. The eye arises from the centrifuging of debris and hydrometeors within the tornadic circulation.

Dowell et al. (2005) employed an axisymmetric numerical model to study particle motions and concentrations in tornadoes. We used 1.5-mm-diameter raindrops in the model to produce flow and reflectivity patterns for three different sized tornadoes: medium, large, and very large. The model output then was scanned with a WSR-88D emulator to produce simulated reflectivity and Doppler velocity measurements within the tornadoes.

We found that, except for the rare very large tornado, peak Doppler velocity values associated with a low-reflectivity eye at close range occurred at a smaller radius than in the model tornado. These peak Doppler velocity values also were at a smaller radius than peak values associated with a uniform reflectivity pattern. As distance from the radar increased, the widening radar beam smeared the low-reflectivity eye to produce a more uniform distribution of reflectivity. At the same time, the peak Doppler velocity values approached those obtained for a uniform reflectivity distribution. Thus, in a typical tornado near a WSR-88D, we would expect the presence of a low-reflectivity eye to cause the peak Doppler velocity values to appear at a smaller radius than the radius of the true peak tangential velocities.

Brown, R. A., R. M. Steadham, 2006: Site-specific scanning strategies for WSR-88Ds: Planning for field tests.. Preprints, Annual Meeting, Cleveland, OH, USA, National Weather Association, 46-47.

The lowest elevation angle scanned by all radars in the Weather Surveillance Radar–1988 Doppler (WSR-88D) network is 0.5 deg. Users of Terminal Doppler Weather Radars (TDWRs) and research Doppler radars find that scanning at 0.0 deg reveals the presence of boundaries of forecasting significance that frequently are not evident at 0.5 deg elevation angles. Furthermore, forecasters who prepare warnings based on mountaintop WSR-88D measurements frequently find that the radar overshoots hazardous weather phenomena that threaten the surrounding populace. Simulations indicate that the use of negative elevation angles at mountaintop sites would permit the detection of hazardous weather and would greatly improve the accuracy of surface rainfall and snowfall estimates.
With a basic need for WSR-88Ds to scan at lower elevation angles, the WSR-88D Radar Operations Center—in collaboration with National Weather Service Forecast Offices, National Severe Storms Laboratory, and Federal Aviation Administration—is proposing that each WSR-88D collect data at elevation angles that are best suited for its locale. To test the operational feasibility of lowering elevation angles, a two-year field test is being proposed for six WSR-88Ds, three located on mountaintops and three located on relatively flat terrain. The test plan currently is being evaluated at various administrative levels within the National Weather Service.

Brown, R. A., V. T. Wood, 2005: Interpretation of Doppler velocity patterns. Doppler Radar Theory and Meteorology, Part B, Doppler Radar Meteorological Observations, Federal Meteorological Handbook No. 11 (Revised), NOAA, 6-1-6-20.

Brown, R. A., 2005: Thunderstorms. The Encyclopedia of World Climatology, Springer, 719-724.

Brown, R. A., K. Tarp, 2005: The National Severe Storms Laboratory: 40 Years Young and Going Strong. Preprints, 21st International Conference on Interactive Information and Processing Systems (IIPS) for Meteorology, Oceanography, and Hydrology, San Diego, CA, USA, American Meteorological Society, CD-ROM, XXXX.

In 1964, the U.S. Weather Bureau's National Severe Storms Project (NSSP) moved from Kansas City to Norman and changed its name to the National Severe Storms Laboratory (NSSL). For the next 25 years, NSSL continued NSSP's (and its predecessors') long-standing tradition of improving understanding of severe storms by conducting a data collection program each spring that included surface and upper air mesonetworks, research aircraft, and radars. Over the years, Doppler radars (including dual polarization), an instrumented TV transmitter tower, storm intercept teams, and storm electricity measurements were added. In more recent years, spring programs have become more intermittent because of funding constraints, with many associated with national research programs (involving airborne Doppler radars) in the southern Plains. Since the early 1990s, various NSSL sensors have become mobile with the addition of mobile rawinsonde release vehicles, balloon-borne storm electricity sensors, mesonetwork instruments on the tops of cars, and Doppler radars mounted on trucks.

Early NSSL research has had a positive impact on improved public safety. Aircraft studies of turbulence in severe thunderstorms, called Project Rough Rider, during the 1960s, 1970s, and early 1980s led to improved commercial airline safety guidelines in the vicinity of thunderstorms. NSSL Doppler radar studies of thunderstorm mesocyclones and tornadoes during the 1970s led to the decision by the National Weather Service (NWS), U.S. Air Force's Air Weather Service, and Federal Aviation Administration (FAA) to include Doppler capability in their updated operational WSR-88D and Terminal Doppler Weather Radar networks. The WSR-88D has helped forecasters significantly improve severe thunderstorm and tornado warnings, saving countless lives. NSSL continues to support the NWS and FAA by developing and refining radar algorithms for identifying severe weather phenomena and estimating precipitation accumulations, and by helping to design better radar acquisition and processing equipment. A program is currently underway to collect data much faster using a newly-constructed phased array Doppler radar.

By the mid 1980s, NSSL was developing an expertise in numerical modeling. Various techniques, including ensembles, are being investigated to improve the numerical prediction of storm-scale, mesoscale, and synoptic-scale processes. In 1997, soon after the National Severe Storms Forecast Center in Kansas City changed its name to the Storm Prediction Center (SPC), it moved to Norman. With the SPC being collocated with NSSL, there have been many opportunities for NSSL meteorologists to help SPC forecasters develop improved severe storm forecasting techniques, including the application of probabilistic forecasting techniques. Thus, through its various research activities during the past 40 years, NSSL has been instrumental in advancing the state of the art of severe storm detection and prediction.

Brown, R. A., B. A. Flickinger, E. Forren, D. M. Schultz, D. Sirmans, P. L. Spencer, V. T. Wood, C. L. Ziegler, 2005: Improved detection of severe storms using experimental fine-resolution WSR-88D measurements. Weather and Forecasting, 20, 3-14.

NSSL Outstanding Scientific Paper Award

Doppler velocity and reflectivity measurements from WSR-88D (Weather Surveillance Radar - 1988 Doppler) radars provide important input to forecasters as they prepare to issue short-term severe storm and tornado warnings. Current-resolution data collected by the radars have an azimuthal spacing of 1.0° and range spacing of 1.0 km for reflectivity and 0.25 km for Doppler velocity and spectrum width. To test the feasibility of improving data resolution, National Severe Storms Laboratory's test-bed WSR-88D (KOUN) collected data in severe thunderstorms using 0.5° azimuthal spacing and 0.25 km range spacing,resulting in eight times the resolution for reflectivity and twice the resolution for Doppler velocity and spectrum width. Displays of current-resolution WSR-88D Doppler velocity and reflectivity signatures in severe storms were compared with displays showing finer-resolution signatures. At all ranges, fine-resolution data provided better depiction of severe storm characteristics. Eighty-five percent of mean rotational velocities derived from fine-resolution mesocyclone signatures were stronger than velocities derived from current-resolution signatures. Likewise, about 85% of Doppler velocity differences across tornado and tornadic vortex signatures were stronger than values derived from current-resolution data. In addition, low-altitude boundaries were more readily detected using fine-resolution reflectivity data. At ranges greater than 100 km, fine-resolution reflectivity displays revealed severe storm signatures, such as bounded weak echo regions and hook echoes, which were not readily apparent on current-resolution displays. Thus, the primary advantage of fine-resolution measurements over current-resolution measurements is the ability to detect stronger reflectivity and Doppler velocity signatures at greater ranges from a WSR-88D.

Brown, R. A., R. M. Steadham, B. A. Flickinger, R. R. Lee, D. Sirmans, V. T. Wood, 2005: New WSR-88D volume coverage pattern 12: Results of field tests. Weather and Forecasting, 20, 385-393.

For the first time since the installation of the national network of WSR-88D radars, a new scanning strategy -- Volume Coverage Pattern 12 -- has been added to the suite of scanning strategies. VCP 12 is a faster version of VCP 11 and has denser vertical sampling at lower elevation angles. This note discusses results of field tests in Oklahoma and Mississippi during 2001 - 2003 that led to the decision to implement VCP 12. Output from meteorological algorithms for a test-bed radar using an experimental VCP were compared with output for a nearby operational WSR-88D using VCP 11 or 21. These comparisons were made for severe storms that were at comparable distances from both radars. Findings indicate that denser vertical sampling at lower elevation angles leads to earlier and longer algorithm identifications of storm cells and mesocyclones, especially those more distant from a radar.

Brown, R. A., J. M. Lewis, 2005: Path to NEXRAD: Doppler radar development at the National Severe Storms Laboratory. Bulletin of the American Meteorological Society, 86, 1459-1470.

In this historical paper, we trace the scientific- and engineering-based steps at the National Severe Storms Laboratory (NSSL) and in the larger weather radar community that led to the development of NSSL's first 10-cm wavelength pulsed Doppler radar. This radar was the prototype for the current NEXRAD (NEXt generation weather RADar) or WSR-88D (Weather Surveillance Radar-1988 Doppler) Network.

We track events, both political and scientific, that led to the establishment of NSSL in 1964. The vision of NSSL's first director, Edwin Kessler, is reconstructed through access to historical documents and oral history. This vision included the development of Doppler radar where research was to be meshed with the operational needs of the U.S. Weather Bureau and its successor the National Weather Service.

Realization of the vision came through steps that were often fitful, where complications arose due to personnel concerns, and where there were always financial concerns. The historical research indicates that: (1) the engineering prowess and mentorship of Roger Lhermitte was at the heart of Doppler radar development at NSSL; (2) key decisions by Kessler in the wake of Lhermitte's sudden departure in 1967 proved crucial to the ultimate success of the project; (3) research results indicated that Doppler velocity signatures of mesocyclones are a precursor of damaging thunderstorms and tornadoes; and (4) results from field testing of the Doppler-derived products during the 1977-1979 Joint Doppler Operational Project -- especially the noticeable increase in the verification of tornado warnings and an associated marked decrease in false alarms -- led to the government decision to establish the NEXRAD network.

Brown, R. A., K. L. Torgerson, 2005: Interpretation of single-Doppler radar signatures in a V-shaped hailstorm: Part II – Evolution of updraft interactions with ambient midaltitude flow. National Weather Digest, 29, 65-80.

Part II of this two-part descriptive study documents characteristics and evolution of the midaltitude flow field arising from interactions of ambient flow with the updraft region of a North Dakota multicell hailstorm. While only single-Doppler radar measurements were available, there were sufficient details in reflectivity and Doppler velocity features to provide interesting deductions about the interactions. The updraft region, located at the upstream end of the storm, typically consisted of two or three actively growing updrafts. Maximum wind speeds occurred along the lateral flanks of the updraft region. The center of the resulting wake region was characterized by a midaltitude channel of low-speed air extending downstream from the middle of the updraft region. Characteristics of the resultant midaltitude vorticity couplet straddling the updraft region did not appear to support the theoretical concept that couplets arise from vertical tilting of low-altitude horizontal vortex tubes. Rather, the vertical momentum of individual updrafts appeared to have collectively presented enough resistance to the approaching midaltitude environmental flow that air slowed down as it flowed through the porous updraft region. As air farther upstream approached the wall of slower-moving air, some of the air was diverted, increasing speed as it flowed around the sides of the updraft region.

Brown, R. A., T. A. Niziol, V. T. Wood, 2005: Improved WSR-88D detection of shallow lake-effect snowstorms over Lake Ontario: Simulations of lowered elevation angles. Preprints, Annual Meeting, St. Louis, MO, USA, National Weather Association, 22-23.

Currently, National Weather Service WSR-88D radars do not operate below +0.5 deg. Consequently, shallow lake-effect snowstorms over and around Lake Ontario pose a detection and warning problem for the Buffalo NWS Forecast Office. We use simulated scanning strategies to investigate how much detections would increase using lower elevation angles for the three closest New York State WSR-88Ds: Montague (KTYX), Buffalo (KBUF), and Binghamton (KBGM). Two Canadian radars on the north side of the lake—that operate as low as 0.0 deg—also are considered.

The Montague radar is located east of Lake Ontario on top of the Tug Hill Plateau 520 m above the lake. Using the current scanning strategies, 2-km-deep snowstorms are detectable to a range of only 100 km from the radar (covering the eastern quarter of the lake). The Buffalo radar covers the western half of the lake. Being farther from the lake, the Binghamton radar covers snowstorms over the southern lake shore.

Simulations show that, when the lowest elevation angle for KTYX is decreased to –0.3 deg, the range of detection of shallow snowstorms increases by 100 km. Lowering the lowest elevation angle for KBUF and KBGM to +0.3 deg increases the coverage range by 20 km. By lowering the scanning strategies for these three radars and operating in conjunction with the Canadian radars, lake-effect storms would be detected over the entire lake and surrounding coastal regions.

Brown, R., V. Wood, 2005: Evaluation of the Velocity Dealiasing Algorithm modified for super-resolution WSR-88D data. Task 5.1, FY 2005 Memo. of Understanding between NWS Radar Operations Center and NSSL, Final Report, 13 pp.

Brown, R. A., 2005: Experimental high-resolution WSR-88D measurements in severe storms: Part II – A tornadic supercell storm. Task 5.3, FY 2005 Memo. of Understanding between NWS Radar Operations Center and NSSL, Final Report, 20 pp.

Brown, R. A., V. T. Wood, 2005: Improvement of WSR-88D VAD winds: Part I – Status report. Task 4, FY 2005 Memo. of Understanding between NWS Radar Operations Center and NSSL, Final Report, 39 pp.

Burgess, D. W., T. D. Crum, R. J. Vogt, 2008: Impact of wind farms on WSR-88D radars. Extended Abstracts, 24rd Conference on Interactive Information Processing Systems (IIPS), New Orleans, LA, USA, AMS, CD-ROM, bB.3.

Burgess, D. W., 2008: An Aircraft Penetration Through a Rear-Flank Downdraft: Revisiting an old case.. Extended Abstracts, 24th Conf. on Severe Local Storms, Savannah, GA, USA, American Meteorological Society, 4.2.

Burgess, D. W., T. Crum, R. J. Vogt, 2007: Impacts of wind turbine farms on WSR-88D radars. Preprints, 33rd Int. Conf. on Radar Meteor., 6-10 August, 2007, Cairns, Australia, AMS, CD-ROM, 13B.6.

Burgess, D. W., R. H. Johns, C. A. Doswell, J. A. Hart, M. S. Gilmore, S. F. Piltz, 2006: The Tri-State Torndao of 18 March 1925, Part I: Re-examination of the Damage Path. Extended Abstracts, 23rd Conference on Severe Local Storms, St. Louis, MO, USA, American Meteorological Society, 18.1.

Burgess, D. W., M. A. Fresch, 2006: The ROC/NSSL Technology Transfer MOU: A Success Story in Radar Applications Technology Transfer. Extended Abstracts, 22nd Internation Conference on Interactive Information Processing Systems (IIPS), Atlanta, GA, USA, American Meteorological Society, 9.2.

Burgess, D. W., D. C. Dowell, L. J. Wicker, A. Witt, 2005: Detailed comparison of observed and modeled tornadogenesis. Preprints, 32nd Conf. on Radar Meteorology, Albuquerque, NM, USA, American Meteorological Society, CD-ROM, 10R.4.

Cintineo, J. L., T. M. Smith, V. Lakshmanan, K. L. Ortega, 2009: A real-time automated method to determine forecast confidence associated with tornado warnings. Extended Abstracts, 25th Conference on Interactive Information Processing Systems for Meteorology, Oceanography, and Hydrology, Phoenix, AZ, USA, American Meteorological Society, 4B.1.

This presentation describes the use of severe weather products derived from the coterminous United States (CONUS) radar network and model analysis fields to determine the confidence-level of National Weather Service-issued tornado warnings. Severe weather attributes such as low-level shear, reflectivity at -20C and the size of the convective core were extracted (within the geographic and temporal extent of the warning polygons) from the real-time grids produced by the Warning Decision Support System -- Integrated Information (WDSS-II). The initial values of these severe weather parameters at the time the warning was issued were used to determine the conditional probability that a tornado would occur within the spatial and temporal bounds of the warning. The results are based on NWS tornado warnings from May and July of 2008, and also based on verification data from the Storm Prediction Center's storm data, which were preliminary at the time the analysis was performed. Conditional probabilities are shown from two products: 0-2km azimuthal shear, and vertically integrated liquid. Once a warning is issued, it is possible to use this conditional probability to objectively assign a confidence value with the warning in real-time.

Available online at ://http://ams.confex.com/ams/89annual/techprogram/paper_150730.htm.

Crowell, S., D. Williams, C. Mavriplis, L. J. Wicker, 2009: Comparison of Traditional and Novel Discretization Methods for Advection Models in Numerical Weather Prediction. ICCS 2009, Part II, Lecture Notes in Computational Science 5545, G. Allen, J. Nabrzyski, E. Seidel, G. D. van Albada, J. Dongarra, P. M. Sloot, Ed(s)., Springer-Verlag, 263-272.

Numerical weather prediction has been dominated by low order finite difference methodology over many years. The advent of high performance computers and the development of high order methods over the last two decades point to a need to investigate the use of more advanced numerical techniques in this field. Domain decomposable high order methods such as spectral element and discontinuous Galerkin, while generally more expensive (except perhaps in the context of high performance computing), exhibit faster convergence to high accuracy solutions and can locally resolve highly nonlinear phenomena. This paper presents comparisons of CPU time, number of degrees of freedom and overall behavior of solutions for finite difference, spectral difference and discontinuous Galerkin methods on two model advection problems. In
particular, spectral differencing is investigated as an alternative to spectral-
based methods which exhibit stringent explicit time step requirements.

Elmore, K. L., K. A. Scharfenberg, C. Legett, 2007: The NSSL winter hydrometeor classification ground truth program: Public involvement in science. Preprints, 31st Intl. Conf. on Radar Meteor., Cairns, Australia, Amer. Meteor. Soc., CD-ROM, P10.9.

During the winter of 2006-2007, a concerted effort was made by the National Severe Storms Laboratory to collect polarimetric radar data using the KOUN radar during winter precipitation events. Simultaneously, observations of precipitation type within a radius of 150 km of KOUN were solicited from the public. Public response has resulted in about 2500 individual observations of winter precipitation type over the course of three major events. These data are intended to be used to both verify the current hydrometeor classification algorithm performance in winter weather events, and to enhance the algorithm's performance. This paper discusses the nature of the ground truth data collected, its overall utility, the nature and scope of quality assurance checking, how event timing affects observation availability, how best to solicit and encourage public participation, and examples of how the data are being used.

Elmore, K. L., M. E. Baldwin, D. M. Schultz, 2006: Field Significance Revisited: Spatial Bias Errors in Forecasts as Applied to the Eta Model. Monthly Weather Review, 134, 519-531.

The spatial structure of bias errors in numerical model output is valuable to both model developers and operational forecasters, especially if the field containing the structure itself has statistical significance in the face of naturally occurring spatial correlation. A semi-parametric
Monte Carlo method, along with a moving blocks bootstrap method is used to determine the field significance of spatial bias errors within spatially correlated error fields. This process can be completely automated, making it an attractive addition to the verification tools already in use. The process demonstrated here results in statistically significant spatial bias error fields at any arbitrary
significance level.

To demonstrate the technique, 0000 and 1200 UTC runs of the operational Eta model and the operational Eta model using the Kain–Fritsch convective parameterization scheme are examined. The resulting fields for forecast errors for geopotential heights and winds at 850, 700, 500, and 250 hPa over a period of 14 months (26 January 2001 through 31 March 2002) are examined and compared using the verifying initial analysis. Specific examples are shown, and some plausible causes for the resulting significant bias errors are proposed.

Elmore, K. L., D. M. Schultz, M. E. Baldwin, 2006: The Behavior of Synoptic-Scale Errors in the Eta Model. Monthly Weather Review, 134, 3355-3366.

A previous study of the mean spatial bias errors associated with operational forecast models motivated an examination of the mechanisms responsible for these biases. One hypothesis for the cause of these errors is that mobile synoptic-scale phenomena are partially responsible. This paper explores this hypothesis using 24-h forecasts from the operational Eta model and an experimental version called the EtaKF.
For a sample of 44 well-defined upper-level short-wave troughs arriving on the west coast of the United States, 70% were underforecast (as measured by the 500-hPa geopotential height), a likely result of being undersampled by the observational network. For a different sample of 45 troughs that could be tracked easily across the country, consecutive model runs showed that the height errors associated with 44% of the troughs generally decreased in time, 11% increased in time, 18% had relatively steady errors, 2% were uninitialized entering the west coast, and 24% exhibited some other kind of behavior. Thus, landfalling short-wave troughs were typically underforecast (positive errors, heights too high), but these errors tended to decrease as they moved across the United States, likely a result of being better initialized as the troughs became influenced by more upper-air data. Nevertheless, some errors in short-wave troughs were not corrected as they fell under the influence of supposedly increased data amount and quality. These results indirectly show the effect that the amount and quality of observational data has on the synoptic-scale errors in the models. On the other hand, long-wave ridges tended to be underforecast (negative errors, heights too low) over a much larger horizontal extent.
These results are confirmed in a more systematic manner over the entire dataset by segregating the model output at each grid point by the sign of the 500-hPa relative vorticity. Although errors at grid points with positive relative vorticity are small but positive in the western United States, the errors become large and negative farther east. Errors at grid points with negative relative vorticity, on the other hand, are generally negative across the United States. A large negative bias observed in the Eta and EtaKF over the southeast United States is believed to be due to an error in the longwave radiation scheme interacting with water vapor and clouds. This study shows that model errors may be related to the synoptic-scale flow, and even large scale features such as long-wave troughs can be associated with significant large-scale height errors.

Available online at ://http://ams.allenpress.com/.

Elmore, K., 2005: Alternatives to the Chi-Square test for evaluating rank histograms from ensemble forecasts. Weather and Forecasting, 20, 789-795.

Erlingis, J. M., J. J. Gourley, T. Smith, K. L. Ortega, 2009: Development of a detailed database of flash flood observations. Extended Abstracts, 23rd Conf. on Hydrology, Phoenix, AZ, USA, AMS, JP2.8.

The primary tool used in the National Weather Service to provide guidance toward the likelihood of imminent flash flooding is the Flash Flood Monitoring and Prediction system (FFMP). FFMP “triggers” when rainfall amounts exceed a 1-, 3-, or 6-hour accumulation threshold, or flash flood guidance (FFG), over basins less than 260 km2. It has been noted that legacy or county-wide FFG values are derived from soil states produced by the Sacramento model which operates on basins up to 4000 km2 at a 6-hourly time step. New, gridded approaches toward deriving FFG (GFFG) have emerged in order to address this scale mismatch. A high-resolution, accurate flash flood observation database was needed in order to evaluate the new GFFG methods relative to the legacy FFG approach.

The Severe Hazards Analysis and Verification Experiment (SHAVE) has been in operation at the National Severe Storms Laboratory since 2006. Undergraduate students use radar-based products and digital telephone databases, all accessible within Google Earth, in order to call and poll the public about the occurrence and severity of hail, wind, and now flash floods. This paper discusses the criteria used to prompt phone calls and the information requested from the public. We show statistics and make some initial inferences based on the flood calls that were made during the summer of 2008. It is envisioned that this database combined with streamflow observations and Storm Data reports will lead to better tools to predict the likelihood of flash floods.

Available online at ://http://ams.confex.com/ams/89annual/techprogram/paper_148661.htm.

Gourley, J. J., P. Tabary, J. Parent-du-Chatelet, 2007: Empirical estimation of attenuation from differential propagation phase measurements at C-band. Journal of Applied Meteorology and Climatology, 46, 306-317.

Gourley, J. J., P. Tabary, J. Parent-du-Chatelet, 2007: A fuzzy logic algorithm for the separation of precipitating from non-precipitating echoes using polarimetric radar observations. Journal of Atmospheric and Oceanic Technology, 24, 1439-1451.

Gourley, J. J., P. Tabary, J. Parent-du-Chatelet, 2006: Data quality of the Meteo-France C-band polarimetric radar. Journal of Atmospheric and Oceanic Technology, 23, 1340-1356.

Gourley, J. J., B. E. Vieux, 2006: A method for identifying sources of model uncertainty in rainfall-runoff simulations. Journal of Hydrology, 327, 68-80.

Gourley, J. J., B. E. Vieux, 2005: A Method for Evaluating the Accuracy of Quantitative Precipitation Estimates from a Hydrologic Modeling Perspective. Journal of Hydrometeorology, 6, 115-133.

Jorgensen, D. P., R. M. Rauber, K. F. Heideman, M. E. Fernau, M. A. Friedman, A. L. Schein, 2007: JOURNALS AND MONOGRAPHS: The evolving publication process of the AMS. The history of scholarly publications of the AMS. Bulletin of the American Meteorological Society, 88, 1122-1126.

Jorgensen, D. P., R. M. Rauber, K. F. Heideman, M. E. Fernau, M. A. Friedman, A. L. Schein, 2007: JOURNALS AND MONOGRAPHS: The evolving publication process of the AMS. What's new? The electronic workflow. Bulletin of the American Meteorological Society, 88, 1131-1134.

Jorgensen, D. P., R. M. Rauber, K. F. Heideman, M. E. Fernau, M. A. Friedman, A. L. Schein, 2007: JOURNALS AND MONOGRAPHS: The evolving publication process of the AMS. What determines how much we pay? The cost of AMS publications. Bulletin of the American Meteorological Society, 88, 1129-1131.

Jorgensen, D. P., R. M. Rauber, K. F. Heideman, M. E. Fernau, M. A. Friedman, A. L. Schein, 2007: JOURNALS AND MONOGRAPHS: The evolving publication process of the AMS. What happens to my paper after it is sent to the AMS? Peer review and publication. Bulletin of the American Meteorological Society, 88, 1126-1129.

Kuhlman, K. M., D. R. MacGorman, M. I. Biggerstaff, P. R. Krehbiel, 2009: Lightning initiation in the anvils of two supercell storms. Geophysical Research Letters, 36, L07802.

Previous studies of lightning in anvil clouds have reported that flashes began in or near the storm core and propagated downwind into the anvil. It had been thought that flashes could not be initiated far downwind in the anvil, because anvil charge was thought to be produced mainly in the storm’s deep updraft and to decrease with distance into the anvil. Here we report observations of the in-cloud development of lightning flashes in the anvils of two supercell storms, including the first observations of flashes that began in the anvil 30–100 km from the cores of the storms and propagated upwind back toward the cores. Interaction between charge regions in the two converging anvils of adjoining storms appeared to cause some of the distant flash initiations, but a local charging mechanism in the anvil likely also contributed to the flash initiations. All flashes that struck ground beneath the distant anvil transferred negative charge to ground instead of the positive charge usually transferred to ground there, an apparent consequence of the parent storm having an inverted-polarity electrical structure.

Kuhlman, K. M., E. Gruntfest, K. A. Scharfenberg, G. J. Stumpf, 2009: Beyond Storm-Based Warnings: An Advanced WAS*IS Workshop to study communication of probabilistic hazardous weather information.. Extended Abstracts, 4th Symp. on Policy and Socio—Economic Research, Phoenix, AZ, USA, Amer. Meteor. Soc., CD-ROM, 3.5.

In September 2008, the National Weather Center hosted an Advanced Weather and Society Integrated Studies (WAS*IS) workshop. This workshop was designed to bring together research meteorologists at the NOAA Hazardous Weather Testbed experimental warning program, and a group of stakeholders representing a diverse user community, to integrate societal impact research at the beginning stages of the development of new gridded probabilistic hazardous weather information. The objectives of the workshop were to: 1) introduce new technologies/directions to a diverse spectrum of potential future collaborators, 2) define and address the needs of a broad spectrum of end-users, 3) clarify and suggest new ways to communicate uncertainty and storm information via emerging technologies, 4) define new measures of success to properly assess service, including changing concepts of storm verification including close calls and false alarms, 5) provide suggestions for the evolution of the Experimental Warning Program, designing spring experiments with stakeholders goals, 6) develop ideas for new ways to change the culture within all levels of the National Weather Service to facilitate operational implementation of these concepts, and 7) create visibility and consider possible future funding opportunities for Hazardous Weather Testbed activities and stakeholder interactions. We will discuss some of the outcomes of this workshop, including the cross-over activities with the development of a Next-Generation Warning Tool for the NWS.

Available online at ://http://ams.confex.com/ams/pdfpapers/150887.pdf.

Kuhlman, K. M., D. R. MacGorman, M. I. Biggerstaff, 2008: Spatial distribution of lightning data relative to kinematics in a HP tornadic supercell storm during TELEX. Preprints, 3rd Annual Conference on Applications of Lightning Data, New Orleans, LA, USA, American Meteorological Society, P1.3.

The Thunderstorm Electrification and Lightning Experiment (TELEX) observed a high-precipitation tornadic supercell storm on 29 May 2004. The available observation systems included the Oklahoma Lightning Mapping Array (LMA), the KOUN S-Band polarimetric radar, and two mobile SMART-R C-Band radars. Thunderstorm charge is thought to be produced by microphysical interactions between graupel and cloud ice followed by differential sedimentation to produce regions of net charge. If so, the kinematics of the storm govern spatial relationships between regions of microphysical charging and the location and geometry of those charge regions.

On 29 May 2004, lightning flashes near the core of this storm, although quite frequent, tended to have shorter duration and smaller horizontal extent than typical flashes in other storms having less frequent lightning. We suggest that this is due, at least in part, to small pockets of opposite charge lying in close proximity to each other. Thus, each polarity of lightning leader propagates only a relatively short distance before reaching regions of unfavorable electrical potential. In the anvil, however, lightning extended tens of kilometers from the reflectivity cores in roughly horizontal layers, consistent with the charge spreading through the anvil in broad sheets. Though lightning has been previously observed in anvils, typically this lightning is initiated in or near the core of the storm and extends out into the anvil. Yet, in the 29 May 2004 storm, flashes initiated in the anvil region and the subsequent leaders progressed back towards the core of the storm. Some of these flashes were negative cloud-to-ground flashes that initiated over 50 km away from the core and struck ground beneath the anvil close to the initiation point. We hypothesize that interaction between the anvil of this supercell and a somewhat lower anvil of opposite polarity from a weaker left-moving cell to the north was responsible for initiating this lightning.

Available online at ://http://www.ametsoc.org.

Kuhlman, K. M., T. M. Smith, G. J. Stumpf, K. L. Ortega, K. L. Manross, 2008: Experimental probabilistic hazard information in practice: Results from the 2008 EWP Spring Program. Extended Abstracts, 24th Conference on Severe Local Storms, Savannah, GA, USA, American Meteorological Society, 8A.1.

The National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) has recently transitioned to "storm-based" warnings from county-based warnings. These warnings are increasingly used by graphical applications for television, the Internet, and cell phones to better communicate specific information about hazardous weather. With the rapid updates in technology and communication, the NWS can continue to build upon the storm-based warnings to better communicate specifics in uncertainty, space, and time to advanced and special-need users.

During the 6 week period of 27 April - 7 June 2008, the NOAA Hazardous Weather Testbed in Norman, OK hosted multiple visiting NWS and Environment Canada forecasters for the Experimental Warning Program (EWP). The forecasters had the opportunity to issue probabilistic guidance on several real-time severe weather events across the continental United States and an archive event from 13 August 2007 in northeast North Dakota. Each forecaster was asked to identify areas of a storm where a threat was possible, either at the current time or near future (less than 60 min) and determine a probability associated with that threat (current and at a chosen future time). The project focused on three different threats: Tornado, Hail (greater than .75 in), and Wind (greater than 50 kts). Probabilistic warning forecasts made throughout the six week period and from the archive event will be compared to the high resolution data from the Severe Hazards Analysis & Verification Experiment (SHAVE) to determine skill and reliability of the forecasts and how this guidance should be updated for future use.

Available online at ://http://ams.confex.com/ams/24SLS/techprogram/paper_142027.htm.

Kuhlman, K. M., E. R. Mansell, C. L. Ziegler, M. I. Biggerstaff, D. R. MacGorman, D. C. Dowell, 2008: EnKF data assimilation and dual-Doppler analysis of the 29 May 2004 Geary, Oklahoma supercell. Proc. 24th Conference on Severe Local Storms, Savannah, GA, USA, American Meteorological Society, P5.1.

On 29 May 2004, a long-track supercell storm moved across Oklahoma producing multiple tornadoes and numerous reports of large hail. Two mobile, C-band, Doppler (SMART-R) radars collected data in 2.5 min volume scans almost continuously for more than three hours. Dual-Doppler analyses were completed for select times using a1 km grid spacing and a 2-pass Barnes objective analysis in the interpolation of radial velocities and reflectivity to a Cartesian grid following Majcen et al (2008).

The focus of the radar data assimilation for this study is to retrieve the state of the storm rather than to develop forecast applications. For this purpose, the ensemble Kalman filter (EnKF) technique is used to assimilate reflectivity and/or radial velocity data into the model from SMART radar at approximately five minute intervals. Comparisons of the simulations employing EnKF to a simulation without data assimilation and to the dual-Doppler syntheses at various times of the storm's life-cycle will be presented. These results will be used to quantify the agreement between the simulation and the observations providing background such that future studies may use the simulations in order to to retrieve unobserved fields.

Available online at ://http://ams.confex.com/ams/24SLS/techprogram/paper_142031.htm.

Kuhlman, K., D. MacGorman, D. Rust, P. Krehbiel, B. Rison, 2007: Lightning in the anvil region of a supercell storm. Preprints, 13th International Conference on Atmospheric Electricity, Beijing, China, IUGG/Commission on Atmospheric Electricity, PS5-8.

The Thunderstorm Electrification and Lightning Experiment (TELEX) took place in central Oklahoma during the 2003 and 2004 convective seasons to study the lightning, dynamics and microphysics of thunderstorms. One storm from this field project, a high-precipitation tornadic supercell occurred on 29 May 2004. In this storm, the Oklahoma Lightning Mapping Array detected lightning extending over one hundred kilometers away from the core of the supercell. Lightning is known to occur in the anvil region of supercells; typically this lightning is initiated in the core of the storm and extends out through the anvil. In the 29 May 2004 storm, however, some flashes actually initiated in the anvil region and the subsequent leaders progressed back towards the core of the storm. Some of these flashes were negative cloud-to-ground flashes that initiated over 50 km away from the core and struck ground beneath the anvil close to the initiation point. It appears that interaction between the anvil of this supercell and an anvil of opposite polarity from a weaker left-moving cell to the north was responsible for initiating this lightning.

Kuhlman, K. M., C. L. Ziegler, E. R. Mansell, D. R. MacGorman, J. M. Straka, 2006: Numerically Simulated Electrification and Lightning of the 29 June 2000 STEPS Supercell Storm. Monthly Weather Review, 134, 2734-2757.

A three-dimensional dynamic cloud model incorporating airflow dynamics, microphysics, and thunderstorm electrification mechanisms is used to simulate the first 3 h of the 29 June 2000 supercell from the Severe Thunderstorm Electrification and Precipitation Study (STEPS). The 29 June storm produced large flash rates, predominately positive cloud-to-ground lightning, large hail, and an F1 tornado. Four different simulations of the storm are made, each one using a different noninductive (NI) charging parameterization. The charge structure, and thus lightning polarity, of the simulated storm is sensitive to the treatment of cloud water dependence in the different NI charging schemes. The results from the simulations are compared with observations from STEPS, including balloon-borne electric field meter soundings and flash locations from the Lightning Mapping Array. For two of the parameterizations, the observed “inverted” tripolar charge structure is well approximated by the model. The polarity of the ground flashes is opposite that of the lowest charge region of the inverted tripole in both the observed storm and the simulations. Total flash rate is well correlated with graupel volume, updraft volume, and updraft mass flux. However, there is little correlation between total flash rate and maximum updraft speed. Based on the correlations found in both the observed and simulated storm, the total flash rate appears to be most representative of overall storm intensity.

Available online at ://http://www.ametsoc.org.

Kuhlman, K., D. MacGorman, M. Biggerstaff, W. D. Rust, T. Schuur, C. Ziegler, P. Krehbiel, 2006: Lightning and radar observatons of the 29 May 2004 supercell during TELEX. Preprints, 2nd Conference on Meteorological Applications of Lightning Data, Atlanta, GA, USA, American Meteorological Society, 3.3.

Langston, C., J. Zhang, K. Howard, 2007: Four-Dimensional Dynamic Radar Mosaic. Journal of Atmospheric and Oceanic Technology, 24, 776-790.

MacGorman, D. R., W. D. Rust, T. J. Schuur, M. I. Biggerstaff, J. M. Straka, C. L. Ziegler, E. R. Mansell, E. C. Bruning, K. M. Kuhlman, N. R. Lund, N. S. Biermann, C. Payne, L. D. Carey, P. R. Krehbiel, W. Rison, K. B. Eack, W. H. Beasley, 2008: TELEX: The Thunderstorm Electrification and Lightning Experiment. Bulletin of the American Meteorological Society, 89, 997-1013.

The field program of the Thunderstorm Electrification and Lightning Experiment (TELEX) took place in central Oklahoma, May–June 2003 and 2004. It aimed to improve understanding of the interrelationships among microphysics, kinematics, electrification, and lightning in a broad spectrum of storms, particularly squall lines and storms whose electrical structure is inverted from the usual vertical polarity. The field program was built around two permanent facilities: the KOUN polarimetric radar and the Oklahoma Lightning Mapping Array. In addition, balloon-borne electric-field meters and radiosondes were launched together from a mobile laboratory to measure electric fields, winds, and standard thermodynamic parameters inside storms. In 2004, two mobile C-band Doppler radars provided high-resolution coordinated volume scans, and another mobile facility provided the environmental soundings required for modeling studies. Data were obtained from twenty-two storm episodes, including several small isolated thunderstorms, mesoscale convective systems, and supercell storms. Examples are presented from three storms. A heavy-precipitation supercell storm on 29 May 2004 produced greater than 3 flashes per second for 1.5 h. Holes in the lightning density formed and dissipated sequentially in the very strong updraft and bounded weak echo region of the mesocyclone. In a small squall line on 19 June 2004, most lightning flashes in the stratiform region were initiated in or near strong updrafts in the convective line and involved positive charge in the upper part of the radar bright band. In a small thunderstorm on 29 June 2004, lightning activity began as polarimetric signatures of graupel first appeared near lightning initiation regions.

Available online at ://http://ams.allenpress.com/archive/1520-0477/89/7/pdf/i1520-0477-89-7-997.pdf.

MacGorman, D. R., K. M. Kuhlman, E. C. Bruning, W. D. Rust, P. R. Krehbiel, M. I. Biggerstaff, 2008: Small, continual lightning activity in the overshooting turret of supercell storms. Proc. 3rd Annual Conference on Applications of Lightning Data, New Orleans, LA, USA, American Meteorological Society, 4.7.

Several supercell storms have occurred within the region in which the Oklahoma Lightning Mapping Array (OKLMA) maps all three spatial dimensions of lightning. These storms span much of the supercell spectrum -- from non-tornadic storms to storms that produced strong tornadoes and from low-precipitation to heavy-precipitation morphologies. As noted by several studies, supercell storms tend to have much larger flash rates than ordinary isolated thunderstorms; maximum rates are typically hundreds of flashes per minute, even when considering only flashes that produce at least ten mapped points per flash. However, the OKLMA indicates that most of the flashes occurring within the main body of the storm during periods of high flash rates have quite small spatial extents, many with a long dimension of 5 km or less. Not usually included in these flash rates are a large number that appear to be isolated points (sometimes called singletons), each failing criteria of distance or time for associating it with other points in a flash. Often determining whether these isolated points are artifacts of the OKLMA is difficult, but in the overshooting top, they present a coherent pattern that appears plausible. They are distributed throughout a cap having horizontal dimensions comparable to that of the overshooting top and sitting near or on the upper surface. They occur continually, though they are too far apart in time or space to be associated in a flash with each other. A comparison with high-resolution reflectivity data for one storm observed by the two mobile 5-cm wavelength SMART-R radars shows that these isolated points were most concentrated near the top of the 40 dBZ echo in the overshooting turret, but some occurred higher, in regions of small reflectivity or just above the overshooting top. These points may be similar to the continual lightning noted by Bill Taylor in the upper region of a severe storm in the early 1980s.

Available online at ://http://www.ametsoc.org.

MacGorman, D. R., T. Mansell, C. Ziegler, J. Straka, 2008: Detailed storm simulations by a numerical cloud model with electrification and lightning parameterizations. Preprints, 20th International Lightning Detection Conference, Tucson, AZ, USA, Vaisala, 28.

We have further developed our three-dimensional cloud model, which includes parameterizations of lightning, corona from ground, ion production and capture, and inductive and noninductive electrification mechanisms, as well as advanced treatments of advection, microphysics, and dynamics. Our most recent improvements have been to improve the model's treatment of microphysics, particularly particle size distributions. This model has been used to simulate many types of storms, from small isolated storms to extensive storm systems, supercell storms, and an idealized hurricane, with excellent similitude to observed kinematic structure in many cases. We will show examples of our simulations and will discuss relationships among the model fields, particularly between lightning and other storm properties. Lightning usually is correlated with precipitation ice mass and with the mass flux through the mixed phase region for updrafts >10 m/s.

MacGorman, D., K. Kuhlman, W. D. Rust, M. Biggerstaff, P. Krehbiel, B. Rison, 2008: Lightning and electrical structure of a heavy-precipitation supercell storm during TELEX. Preprints, 2nd International Lightning Meteorology Conference, Tucson, AZ, USA, Vaisala, 10.

The Thunderstorm Electrification and Lightning Experiment (TELEX) observed a heavy-precipitation (HP) supercell storm in central Oklahoma on 29 May 2004. In a HP supercell storm, the initial location of the mesocyclone, which is the parent rotation of tornadoes, is embedded well within the precipitation of the storm, instead of being on the edge of the storm(as in classic and low-precipitation supercell storms). Two 5-cm wavelength mobile Doppler radars were positioned near the storm and collected volume scans every 3 minutes for 3 h beginning as the storm became supercellular. The storm had supercell characteristics for this entire period. The Oklahoma Lightning Mapping Array provided three-dimensional data throughout the storm’s supercellular stage and provided two-dimensional data from the time of storm initiation in western Oklahoma. A 10-cm wavelength polarimetric radar also provided data for much of this period.
Lightning flash rates became extraordinarily large as the storm evolved into a supercell and its motion turned rightward. Flash rates increased again (to an estimated peak value of almost 500 flashes per minute) shortly before the storm produced a tornado rated F2 on the Fujita scale. During this period, an upward pulse in lightning density extended as high as 18 km MSL in a plume extending above the equilibrium level. Most flashes in the main body of the storm had small spatial extent (3-10 km). Lightning in the overshooting top consisted of continual single-point flashes.
The region of lightning activity pulsed eastward far into the anvil, up to 100 km from the convective core. Up to 5 -CG flashes per minute were initiated in the anvil more than 40 km from the main storm core, and typically came to ground within a few kilometers horizontally of the location of initiation. Because these -CG strikes occur far from the deep convection, they pose a generally unexpected danger to personnel.
A series of minimums in the plan projection of lightning density (i.e., lightning holes) formed just above the bounded weak echo region. A dual-Doppler synthesis of wind during one volume scan shows the lightning hole was co-located with large vertical wind speeds in the rotating updraft. The hole apparently occurred because precipitation particles had little time to grow and gain charge in the strong updraft before they were lifted to upper regions of the storm and advected outward by flow from the diverging updraft. Lightning mapping data suggest that the vertical polarity of the storm’s electrical structure was inverted from the usual polarity, and this appears to be why CG flashes that began in the anvil were -CG flashes.

MacGorman, D., T. Schuur, M. Kumjian, 2008: Total lightning activity during the re-intensification of Tropical Storm Erin over Oklahoma on 18–19 August 2007. Preprints, 24th Conference on Severe Local Storms, Savannah, GA, USA, American Meteorological Society, 7A.5.

The remnants of Tropical Storm Erin made landfall on the Texas coast on 16 August 2007 and reached Oklahoma on 18 August, where it produced tornadoes, severe straight-line winds, and flooding. In west-central Oklahoma (roughly 800 km from the coast), the system re-intensified and formed an eye and rainband structure characteristic of tropical cyclones. The Oklahoma Mesonet indicated that the system eventually produced greater sustained winds (26 m s-1, 58 mph) and a lower central pressure (1001.3 hPa) than it had produced over open water.

The eye, which fluctuated from 5 to 25 km in diameter, was first apparent on lightning and radar displays at 4:50 am local time and began dissipating over Oklahoma City at 9:50 am. Throughout the period during which the eye formed and dissipated, the eye and the majority of the area of rainbands were well within the region in which the Oklahoma Lightning Mapping Array maps lightning in three dimensions and in which the KOUN S-Band radar provides polarimetric data. Both radar displays and displays of lightning density delineated the formation of the eye and rainband well. Convection extended highest and lightning rates were greatest in the rainband on the southeast flank. The height of convection in the rainband decreased as one approached the eye, and the decrease in height extended around the eye as the eye formed. Some long, horizontal flashes extended eastward from storms along the east side of the eye into the region of widespread light precipitation east of the rainband. The appearance of these long horizontal flashes was similar to the lightning structure observed in the stratiform precipitation regions of mesoscale convective systems. As the cyclone structure weakened, convection on the west side of the eye dissipated, and the remnants of the rainband on the east side propagated eastward as a line of storms.

Though the lightning in this system was probably influenced by being over land, this case still may provide clues to what happens electrically in tropical cyclones over open water, where continuous observations of total lightning activity during tropical cyclone intensification and dissipation are not yet available.

Available online at ://http://www.ametsoc.org.

MacGorman, D. R., T. Filiaggi, R. L. Holle, R. A. Brown, 2007: Negative Cloud-to-Ground Lightning Flash Rates Relative to VIL, Maximum Reflectivity, Cell Height, and Cell Isolation. Journal of Lightning Research, 1, 132-147.

This study relates storm cell parameters derived automatically from the Doppler radars of the United States National Weather Service to negative cloud-to-ground lightning activity detected by the United States National Lightning Detection Network. Data from the central United States were processed for over 1200 cells from seventeen days. Each cell’s maximum ground flash rate was compared to a subjective rating of the degree of cell isolation and to three radar-derived cell parameters: maximum reflectivity, maximum vertically integrated liquid (VIL), and the maximum vertical thickness having at least 30 dBZ reflectivity above the 0 deg C isotherm (similar to 30-dBZ cell height). Of the three parameters, the maximum 30-dBZ thickness of cells had the most useful relationship: The mean and modal values of ground flash rates increased with increasing 30-dBZ thickness, and the mean and modal values of 30-dBZ thickness increased with increasing flash rates. However, large ground flash rates provided a better diagnostic for large 30-dBZ thickness than large 30-dBZ thickness provided for large ground flash rates. The degree of cell isolation and the complexity of cell evolution also had a large effect: Cells which were less isolated or whose evolution was more complex were more likely to produce a ground flash and larger ground flash rates. Besides effects of storm complexity and size suggested by previous investigators, we suggest that the more complex charge distribution produced by having older cells nearby improves a cell’s probability of access to the lower positive charge typically needed to initiate negative ground flashes.

MacGorman, D., K. Kuhlman, D. Rust, M. Biggerstaff, T. Schuur, J. Straka, P. Krehbiel, B. Rison, L. Carey, 2007: Lightning and electrical structure of a heavy-precipitation supercell storm during TELEX. Preprints, 13th International Conference on Atmospheric Electricity, Beijing, China, IUGG/Commission on Atmospheric Electricity, OS5-1.

The Thunderstorm Electrification and Lightning Experiment (TELEX) observed a heavy-precipitation (HP) supercell storm in central Oklahoma on 29 May 2004. In a HP supercell storm, the initial location of the mesocyclone, which is the parent rotation of tornadoes, is embedded well within the precipitation of the storm, instead of being on the edge of the storm (as in classic and low-precipitation supercell storms). Two 5-cm wavelength mobile Doppler radars were positioned near the storm and collected volume scans every 3 minutes for 3 h beginning as the storm became supercellular. The storm had supercell characteristics for this entire period. The Oklahoma Lightning Mapping Array provided three-dimensional data throughout the storm’s supercellular stage and provided two-dimensional data from the time of storm initiation in western Oklahoma. A 10-cm wavelength polarimetric radar also provided data for much of this period.
Lightning flash rates became extraordinarily large as the storm evolved into a supercell and its motion turned rightward. Flash rates increased again (to an estimated peak value of almost 500 flashes per minute) shortly before the storm produced a tornado rated F2 on the Fujita scale. During this period, an upward pulse in lightning density extended as high as 18 km MSL in a plume extending above the equilibrium level, and the region of lightning activity pulsed eastward far into the anvil, up to 150 km from the western edge of the storm. A series of minimums in the plan projection of lightning density (i.e., lightning holes) formed just above the bounded weak echo region. A dual-Doppler synthesis of wind during one volume scan shows the lightning hole was co-located with large vertical wind speeds in the rotating updraft. The hole apparently occurred because precipitation particles had little time to grow and gain charge in the strong updraft before they were lifted to upper regions of the storm and advected outward by flow from the diverging updraft. Cloud-to-ground lightning activity in and near heavy precipitation was dominated initially by negative ground flashes, but during part of the supercell phase, evolved to become dominated by positive ground flashes. Lightning mapping data suggest that, when positive ground flashes dominated, the vertical polarity of the storm’s electrical structure was inverted from the usual polarity.

MacGorman, D., K. Kuhlman, E. Bruning, D. Rust, P. Krehbiel, M. Biggerstaff, 2007: Small, continual lightning activity in the overshooting turret of supercell storms. Preprints, 2007 Annual Fall Meeting, San Francisco, CA, USA, American Geophysical Union, AE41A-03.

MacGorman, D., I. Apostolakopoulos, A. Nierow, J. Cramer, N. Demetriades, P. Krehbiel, 2006: Improved Timeliness of Thunderstorm Detection from Mapping a Larger Fraction of Lightning Flashes. Preprints, 1st International Lightning Meteorology Conference, Tucson, AZ, USA, Vaisala, CD-ROM, N/A. [Available from Vaisala, Inc., Tucson Operations, 2705 E. Medina Rd., Tucson, AZ, USA, 85706.]

One application of lightning ground strike mapping systems has been thunderstorm detection. However, the climatological ratio of in-cloud flashes to cloud-to-ground flashes typically is greater than 2:1. Thus, systems that map either cloud flashes or all types of flashes will detect storms more quickly and reliably. The improvement typically is even greater than would be expected simply from the greater number of samples, because the first flashes produced by a storm usually are cloud flashes. However, the improvement obviously is affected by the fraction of flashes that a lightning mapping system detects. Because it costs substantially more to detect a larger fraction of all flashes, one would like to know how much lead time will be added by various levels of lightning detection. The U.S. National Lightning Detection Network (NLDN) being used by the National Weather Service is now capable of detecting roughly 10-20% of cloud flashes, in addition to a much larger fraction of cloud-to-ground flashes, over the contiguous United States. So far, this cloud flash option has been turned on only in a test region. The optical lightning mapper being planned for GOES-R is expected to detect 80-90% of cloud flashes. Some research mapping systems can detect essentially all but the smallest flashes throughout their coverage region. We analyzed the test cloud flash data from the NLDN network to see how much that system’s cloud flash detection would improve thunderstorm detection. Furthermore, we analyzed data from VHF lightning mapping systems that detect almost all flashes, to evaluate how much the timeliness of thunderstorm detection can be improved over what is now achieved with ground strike mapping systems. In north Texas and Oklahoma, 50% of thunderstorms produced a cloud-to-ground flash within 5-10 minutes of their first cloud flash, but in roughly 10% of storms, no cloud-to-ground flash occurred within an hour of the first cloud flash. Behavior was much different in storms over the High Plains of northwest Kansas and northeast Colorado. There it required 30 minutes after the first cloud flash for 50% of storms to produce a cloud-to-ground flash, and 20% of storms produced no cloud-to-ground flash within their first hour of lightning activity. One might expect such a result on the basis of climatological studies showing that cloud flashes comprise at least 90% of all lightning over much of the High Plains and in a few other regions of the country.

MacGorman, D. R., I. Apostolakopoulos, A. Nierow, J. Cramer, N. Demetriades, P. Krehbiel, 2006: Improved timeliness of thunderstorm detection from mapping a larger fraction of lightning flashes. Preprints, International Lightning Meteorology Conference, Tucson, AZ, USA, Vaisala, 7.

MacGorman, D., K. Kuhlman, M. Biggerstaff, D. Rust, P. Krehbiel, 2006: Lightning and radar observations of the 29 May 2004 tornadic HP supercell during TELEX. Preprints, Annual Fall Meeting, San Francisco, CA, USA, American Geophysical Union, AE343A-1056.

MacGorman, D. R., W. D. Rust, P. Krehbiel, W. Rison, E. Bruning, K. Wiens, 2005: The electrical structure of two supercell storms during STEPS. Monthly Weather Review, 133, 2583-2607.

Balloon soundings were made through two supercell storms during the Severe Thunderstorm Electrification and Precipitation Study (STEPS) in summer 2000. Instruments measured the vector electric field, temperature, pressure, relative humidity, and balloon location. For the first time, soundings penetrated both the strong updraft and the rainy downdraft region of the same supercell storm. In both storms, the strong updraft had fewer vertically separated charge regions than found near the rainy downdraft, and the updraft's lowest charge was elevated higher, its bottom being near the 40-dBZ boundary of the weak-echo vault. The simpler, elevated charge structure is consistent with the noninductive graupel-ice mechanism dominating charge generation in updrafts. In the weak-echo vault, the amount of frozen precipitation and the time for particle interactions are too small for significant charging. Inductive charging mechanisms and lightning may contribute to the additional charge regions found at lower altitudes outside the updraft. Lightning mapping showed that the in-cloud channels of a positive ground flash could be in any one of the three vertically separated positive charge regions found outside the updraft, but were in the middle region, at 6-8 km MSL, for most positive ground flashes. Our data are consistent with the electrical structure of these storms having been inverted in polarity from that of most storms elsewhere. We hypothesize that the observed inverted-polarity cloud flashes and positive ground flashes were caused by inverted-polarity storm structure, possibly due to a larger than usual rime accretion rate for graupel in a strong updraft.

MacGorman, D., D. Rust, T. Schuur, M. Biggerstaff, J. Straka, C. Ziegler, E. Mansell, P. Krehbiel, W. Rison, T. Hamlin, L. Carey, E. Bruning, K. Kuhlman, N. Ramig, C. Payne, 2005: Lightning Relative to Storm Structure and Microphysics in TELEX. Polarimetric radar and electrical structure of a multicell storm. Preprints, 32nd Conference on Radar Meteorology, Albuquerque, NM, USA, American Meteorological Society, CD-ROM, 10R.7.

MacGorman, D., 2005: Relationships among electrification, lightning, kinematics, and microphysics: Lessons from the interaction of observations and numerical storm simulations. Extended Abstracts, 2005 Annual Fall Meeting, San Francisco, CA, USA, American Geophysical Union, CD-ROM, AE32A-01.

MacGorman, D., C. L. Ziegler, E. Mansell, W. Beasley, B. Fiedler, 2005: Retrieval and assimilation of storm characteristics from both in-cloud and cloud-to-ground lightning data to improve mesoscale model forecasts. Final report to the Office of Naval Research (ONR Grant # N00014-00-1-0525) 1, 54 pp.

MacGorman, D., C. Ziegler, T. Mansell, J. Straka, P. Krehbiel, B. Rison, T. Hamlin, 2005: Applications of advanced lightning mapping technologies to storm research and weather operations. Preprints, Conference on Meteorological Applications of Lightning Data, San Diego, CA, USA, American Meteorological Society, 2.1.

MacGorman, D. R., W. D. Rust, C. L. Ziegler, T. J. Schuur, E. R. Mansell, M. I. Biggerstaff, J. M. Straka, E. C. Bruning, K. M. Kuhlman, N. R. Ramig, C. D. Payne, N. S. Biermann, P. R. Krehbiel, W. Rison, T. Hamlin, L. D. Carey, 2005: Lightning relative to storm structure, evolution, and microphysics in TELEX. Preprints, 32nd Conference on Radar Meteorology, Albuquerque, NM, USA, American Meteorological Society, 10R.7.

Manross, K. L., T. M. Smith, J. T. Ferree, G. J. Stumpf, 2008: An on-demand user interface for requesting multi-radar, multi-sensor time accumulated products to support severe weather verification. Extended Abstracts, 23rd Conference on Interactive Information Processing Systems, New Orleans, LA, USA, AMS, P2.13.

NSSL has a long history of developing radar based applications and algorithms intended to aid forecasters in warning decision making. With the advent of the WDSSII system, new and more robust algorithms are being developed in short amounts of time. Thanks to the GIS-based Google Earth application, NSSL has been able to display real-time algorithm output via the World Wide Web for feedback on these algorithms. As a result, many of these algorithms have not only proven useful and accurate, but also popular, particularly in short-term post-event storm survey and verification situations. Time accumulated Maximum Expected Size of Hail ("MESH") and time accumulated radar detected maximum low-altitude rotational shear ("Rotation Tracks") are two products that seem to be particularly useful. The latter has been used to aid forecasters in tornado damage surveys performed by National Weather Service (NWS) personnel at numerous Weather Service Forecast Offices. Emergency managers may also find these plots useful for disaster response.

Currently these data are continuously being produced on the CONUS scale and are stored in a short term archive (up to one week). For specific events, or by request, the data can be manually reprocessed for smaller regions and short time scales and are occasionally archived indefinitely. A recently funded proposal has allowed for automated, on-demand requests of these products by end-users. Forecasters may specify region-specific GIS-encoded data for requested time periods using a web-based graphical user interface. This paper details this process as well as explaining the user interface.

Available online at ://http://ams.confex.com/ams/88Annual/techprogram/paper_134621.htm.

Manross, K. L., J. G. LaDue, 2006: New Features of the VCPExplorer: Simulated Precipitation. Extended Abstracts, 22nd International Conference on Interactive Information Processing Systems for Meteorology, Oceanography, and Hydrology, Atlanta, GA, USA, American Meteorological Society, CD-ROM, 2.11. [Available from Kevin L. Manross, National Severe Storms Laboratory, 120 David L. Boren Blvd., Norman, OK, USA, 73072.]

The VCPExplorer is an instructional tool that aides in the visualization of radar scanning strategies, including radar beam propagation path relative to terrain, and radar algorithm dependence on volume coverage pattern (VCP). The VCPExplorer has been used in the Warning Decision Training Branch's (WDTB) Advanced Warning Operations Course (AWOC) and has been upgraded with several new features to simulate radar sampling issues of precipitation. Among the new features are radar estimated rainfall. The user can modify several parameters including ZR relationship, VCP, and reflectivity profile and compare the radar estimated (based on VCP and terrain-based hybrid scan) rainfall to the "true" (based on radar reflectivity at the Earth's surface) rainfall. Other new features include simulated "bright-banding" and sub-cloud evaporation effects on radar reflectivity.

Available online at ://http://ams.confex.com/ams/Annual2006/techprogram/paper_104425.htm.

Manross, K. L., J. G. LaDue, G. Stumpf, 2005: The Volume Coverage Pattern Explorer: A new tool for visualizing radar beam paths. Preprints, 21st International Conference on Interactive Information and Processing Systems (IIPS) for Meteorology, Oceanography, and Hydrology, San Diego, CA, USA, American Meteorological Society, CD-ROM, 5.5.

Mansell, E. R., C. L. Ziegler, D. R. MacGorman, 2007: A Lightning Data Assimilation Technique for Mesoscale Forecast Models. Monthly Weather Review, 135, 1732-1748.

Lightning observations have been assimilated into a mesoscale model for improvement of forecast initial conditions. Data are used from the National Lightning Detection Network (cloud-to-ground lightning detection) and a Lightning Mapping Array (total lightning detection) that was installed in western Kansas–eastern Colorado. The assimilation method uses lightning as a proxy for the presence or absence of deep convection. During assimilation, lightning data are used to control the Kain–Fritsch (KF) convection parameterization scheme. The KF scheme can be forced to try to produce convection where lightning indicated storms, and, conversely, can optionally be prevented from producing spurious convection where no lightning was observed. Up to 1 g/kg of water vapor may be added to the boundary layer when the KF convection is too weak. The method does not employ any lightning–rainfall relationships, but rather allows the KF scheme to generate heating and cooling rates from its modeled convection. The method could therefore easily be used for real-time assimilation of any source of lightning observations. For the case study, the lightning assimilation was successful in generating cold pools that were present in the surface observations at initialization of the forecast. The resulting forecast showed considerably more skill than the control forecast, especially in the first few hours as convection was triggered by the propagation of the cold pool boundary.

Mansell, E., C. L. Ziegler, E. Bruning, 2007: Simulated electrification of a TELEX multicell storm. Preprints, 13th International Conference on Atmospheric Electricity, Beijing, China, International Commission on Atmospheric Electricity, 290-293.

Mansell, E. R., C. L. Ziegler, D. R. MacGorman, 2006: A Lightning Data Assimilation Technique for Mesoscale Forecast Models. Preprints, Second Conference on Meteorological Applications of Lightning Data, Atlanta, GA, USA, American Meteorological Society, 4.2.

Lightning observations have been assimilated into the COAMPS mesoscale model for improvement of forecast initial conditions. Data are used from the National Lightning Detection Network (NLDN, cloud-to-ground lightning detection) and a Lightning Mapping Array (LMA; total lightning detection) that was installed in western Kansas/eastern Colorado. The assimilation method uses lightning as a proxy for the presence or absence of deep convection. During assimilation, lightning data are used to control the Kain-Fritsch (KF) convection parameterization scheme (CPS). The KF scheme can be forced to try to produce convection where lightning indicated storms, and, conversely, can optionally be prevented from producing spurious convection where no lightning was observed. Up to 1 g/kg of water vapor may be added to the boundary layer when the KF convection is too weak. The method does not make any use lightning-rainfall relationships, rather allowing the KF scheme to generate heating and cooling rates from its modeled convection. The method could therefore be used easily for real-time assimilation of any source of lightning observations.

Results will be presented for a warm-season test case 20-21 July 2000, when storms initiated and developed in large systems in Kansas both days. The second round of convection began by 22:00 UTC (20 July), and storm system with strong outflow had developed by 00 UTC on 21 July. Lightning data were assimilated over a 24 hour period (starting at 00 UTC on 20 July), covering the first round of convection and the start of the second. A control run was spun up over the same period only with the usual 12-hourly update cycle. As expected, during the assimilation period the model produces substantially more accurate precipitation (rates and location) than the control forecast. Even when water vapor was added to enhance convection, the rainfall rates were generally less than those indicated by rain gauge data. A forecast was started from the resulting initial condition at 00 UTC on 21 July 2000.

The lightning assimilation was successful in generating the cold pool that was present in the surface observations at initialization of the forecast. The resulting forecast showed considerably more skill than the control forecast, especially in the first few hours as convection was triggered by the propagation of the cold pool boundary.

Available online at ://http://ams.confex.com/ams/Annual2006/techprogram/paper_104180.htm.

Mansell, E. R., D. R. MacGorman, C. L. Ziegler, J. M. Straka, 2005: Charge structure in a simulated multicell thunderstorm. Journal of Geophysical Research, 110, .

A three-dimensional dynamic cloud model is used to investigate electrification of the full life cycle of an idealized continental multicell storm. Five laboratory-based parameterizations of noninductive graupel-ice charge separation are compared. Inductive (i.e., electric field-dependent) charge separation is tested for rebounding graupel-droplet collisions. Each noninductive graupel-ice parameterization is combined with variations in the effectiveness of inductive charging (off, moderate, and strong) and in the minimum ice crystal concentration (10 or 50/L). Small atmospheric ion processes such as hydrometeor attachment and point discharge at the ground are treated explicitly. Three of the noninductive schemes readily produced a normal polarity charge structure, consisting of a main negative charge region with an upper main positive charge region and a lower positive charge region. Negative polarity cloud-to-ground (CG) flashes occurred when the lower positive charge (LPC) region had sufficient charge density to cause high electric fields. Two of the three also produced one or more +CG flashes. The other two noninductive charging schemes, which are dependent on the graupel rime accretion rate, tended to produce an initially inverted polarity charge structure and +CG flashes. The model results suggest that inductive graupel-droplet charge separation could play a role in the development of lower charge regions. Noninductive charging, on the other hand, was also found to be capable of producing strong lower charge regions in the tests with a minimum ice crystal concentration of 50/L.

Ortega, K. L., A. G. Kolodziej, J. Young, C. J. Wilson, A. Witt, T. M. Smith, 2008: Evaluating hail diagnosis techniques using high resolution verification. Extended Abstracts, 24th Conference on Severe Local Storms, Savannah, GA, USA, American Meteorological Society, CD-ROM, P6.5.

During the summers of 2006, 2007 and 2008, the National Severe Storms Laboratory conducted high resolution verification efforts on numerous severe weather events across the U.S. This project was originally called the Severe Hail Verification Experiment (SHAVE), with the name later changed to the Severe Hazards Analysis and Verification Experiment (SHAVE) to reflect differences in how the experiment was conducted. During all three years, the primary goal of SHAVE was to collect hail reports at higher resolution than what is available through Storm Data. This study will evaluate the performance of several hail diagnosis techniques. These techniques include a hail diagnosis algorithm which utilizes several radar reflectivity and velocity based parameters together with environmental data in the vicinity of a storm, and multi-radar, multi-sensor hail diagnosis grids. Results using SHAVE reports will be compared to results using Storm Data to assess whether differences in algorithm skill result from differences in verification data resolution. Also, variations in near-storm environment and storm structure will be compared for several cases.

Available online at ://http://ams.confex.com/ams/24SLS/techprogram/paper_142039.htm.

Ortega, K. L., 2008: Severe weather warnings and warning verification using threat areas. M.S. thesis, School of Meteorology, University of Oklahoma, 50 pp.

On October 1, 2007, the National Weather Service (NWS) changed its warning system from a county-based system to a storm-based system. In the storm-based warning system, the forecaster draws a warning polygon that is supposed to highlight the area under threat from the storm without regard for geopolitical boundaries (such as county boundaries). A leading reason for the change was to reduce the false alarm area caused by warning-by-county. While the goal seems worthwhile, the NWS currently has no tools or capabilities to measure the false alarm area reduction. All warning skill measures, such as probability of detection, are calculated from reports of severe weather; questions arise since the reports are discrete points that are widely separated in space and time. Previous studies (Witt et al. 1998 and Trapp et al. 2006) highlighted not only representativeness concerns, but also problems in accuracy of some reports' time, location and magnitude.
This study will explore the utility of new warning techniques based on threat areas and storm motion. A threat area is defined as an area expected to receive, currently is receiving or has received a severe weather threat. This study will limit its severe weather threat to hail. While NWS techniques allow the forecaster to draw the polygon, the techniques explored in this study will be locked to a storm motion and motion uncertainty to highlight the warned area. Two warning guidance methods will be explored: the first allows the forecaster to highlight the current threat area and that area is translated along the storm motion and motion uncertainty. The second method uses an algorithm to highlight the current threat area by evaluating output from a gridded version of the Hail Detection Algorithm (HDA; Witt et al. 1998). This second method will also ix
explore the capability of classifying the magnitude of the threat and increasing or decaying the classification with time.
This study will also explore the scoring of warnings based on areas and population using two unique datasets. The first dataset is an archive of high-resolution hail verification from the Severe Hail Verification Experiment (SHAVE; Smith et al. 2006) that was conducted at the National Severe Storms Laboratory during the summer of 2006. This verification dataset allowed for the creation and scoring of verification grids created from reflectivity and gridded HDA output. The second dataset is a high-resolution population grid available from Oak Ridge National Laboratory. Scoring the warnings using the population grid can easily answer questions such as "did the warning cover the population under threat?"

Ortega, K. L., T. M. Smith, G. J. Stumpf, 2006: Verification of multi-sensor, multi-radar hail diagnosis techniques. Preprints, Symposium on the Challenges of Severe Convective Storms, Atlanta, GA, USA, American Meteorological Society, CD-ROM, P1.1.

Ortega, K. L., T. M. Smith, K. A. Scharfenberg, 2006: An analysis of thunderstorm hail fall patterns in the Severe Hail Verification Experiment. Preprints, 23rd Conference on Severe Local Storms, St. Louis, MO, USA, AMS, CD-ROM, P2.4.

Available online at ://http://ams.confex.com/ams/23SLS/techprogram/paper_115441.htm.

Ortega, K. L., T. M. Smith, G. J. Stumpf, J. Hocker, L. López, 2005: A comparison of multi-sensor hail diagnosis techniques. Preprints, 21st International Conference on Interactive Information and Processing Systems (IIPS) for Meteorology, Oceanography, and Hydrology, San Diego, CA, USA, American Meteorological Society, P1.11.

Rabin, R. M., J. Hanna, 2008: GOES winter precipitation efficiency algorithm.. Extended Abstracts, Fifth GOES Users Conference, 88th AMS meeting, New Orleans, LA, USA, AMS, P1.34.

Rabin, R. M., T. J. Schmit, 2006: Estimating soil wetness from the GOES sounder. Journal of Atmospheric and Oceanic Technology, 23, 991-1003.

Rabin, R. M., T. Whittaker, 2006: Tool for Storm Analysis Using Multiple Data Sets. Advances in Visual Computing, G. Bebis, R. Boyle, D. Koracin, B. Parvin, Ed(s)., Springer, 571-578.

Rabin, R. M., 2005: Tool for storm analysis using multiple data sets. Published in "Advances in Visual Computing", Lecture Notes in Computer Science (#3804), Bebis et. al, Editors. Published by Springer. Proc. First International Symposium on Visual Computing., Lake Tahoe, NV, USA, University of Nevada-Reno, Desert Research Institute, Berkeley L, 571-578. [Available from Robert Rabin, 120 David L. Boren, Norman, OK, USA, 73072.]

Available online at ://http://www.springeronline.com.

Smith, T. M., V. Lakshmanan, 2008: Real-time and recent historical weather data in Google Earth. Extended Abstracts, 23rd Conference on Interactive Information Processing Systems, New Orleans, LA, USA, AMS, 9B.6.

The National Severe Storms Laboratory (NSSL) utilizes Google Earth as one of several ways to share experimental severe weather products with other researchers and operational meteorologists for evaluation and feedback. A variety of multi-sensor severe weather products are generated by NSSL and shared to Google Earth users via the internet at http://wdssii.nssl.noaa.gov. These products include spatially gridded fields of Vertically Integrated Liquid, Maximum Expected Hail Size, tracks of circulations derived from Doppler velocity data, composite reflectivity, and 30-to-60 minute forecast reflectivity fields, among others. These products, which have a spatial resolution of approximately 1 km by 1 km, are generated every one to five minutes within the Warning Decision Support System – Integrated Information (WDSS-II). The WDSS-II system provides the images in GeoTIFF format which may be imported into most Geographic Information Systems software including virtual globes such as Google Earth.

During the first two years these data have been provided on the internet, they have been used to improve the verification of severe weather events as well as in disaster response and post-event damage assessments. This presentation focuses on the scientific and educational uses of virtual globes to interrogate real-time and archived severe weather products.

Available online at ://http://http://ams.confex.com/ams/88Annual/techprogram/paper_134923.htm.

Smith, T. M., P. L. Heinselman, D. Priegnitz, 2007: Characteristics of microburst events observed with the National Weather Radar Testbed phased array radar. Preprints, 23rd Conference on Interactive Information Processing Systems, San Antonio, TX, USA, AMS, CD-ROM, 7.8.

Microbursts are small-scale (< 4 km diameter) outflows induced by strong downdrafts in thunderstorms that frequently cause damage to property and are a hazard to aviators. Many severe microbursts originate from storm cells that form in regions of moderate-to-high Convective Available Potential Energy (CAPE), weak environmental shear, and environments that are highly unstable to downdraft formation. These storm cells typically have a life cycle of 20-40 minutes, which makes them very difficult to predict.

Automated algorithms that analyze radar data and make short-term predictions for microburst events, as well as detecting low-altitude divergence signatures associated with their outflows, have been implemented for WSR-88D and TDWR systems. These applications rely on microburst “precursors” that may be observed at the higher altitudes of a storm shortly preceding the outflow at the surface to make short-lead-time forecasts of a microburst event. However, microburst events evolve rapidly, and because these radars typically only sample the upper portions of a storm once every 4 to 6 minutes (depending on scanning strategy), they may not sample key precursor features aloft or the near-surface outflow.

This presentation examines damage-producing severe microburst events that occurred in Central Oklahoma during July 2006 that were observed with the National Weather Radar Testbed (NWRT) Phased Array Radar (PAR). These storms formed within 50 km of the PAR site and were sampled with a temporal resolution of 15 to 30 seconds. We will compare the PAR observations of the storms with the KTLX WSR-88D, OKC TDWR, and multi-radar, multi-sensor information from the Warning Decision Support System – Integrated Information.

Available online at ://http://ams.confex.com/ams/pdfpapers/120074.pdf.

Smith, T. M., K. L. Ortega, A. G. Kolodziej, 2007: Enhanced, high-density severe storm verification. Preprints, 23rd Conference on Interactive Information Processing Systems, San Antonio, TX, USA, AMS, CD-ROM, 4B.3.

The Severe Hail Verification Experiment (SHAVE) was conducted during May through August of 2006. Researchers in SHAVE combined radar and environmental information available from the National Severe Storms Laboratory's Warning Decision Support System – Integrated Information (WDSS-II) with geographic information available in Google Earth and other sources. This information was used to identify locations to make targeted telephone calls to the public in regions where storms occurred within minutes of an event in order to collect information about the occurrence, size, and duration of hail. During the experiment, hail swaths from severe thunderstorms were documented at a much higher spatial and temporal resolution than is available in the National Climate Data Center's Storm Data publication and in National Weather Service (NWS) local storm report products.

The presentation shows results from SHAVE and compares the independently collected, high-resolution data with traditional NWS verification data for hail, and discusses the uncertainties associated with both data sets. We discuss the benefits of the improved verification data and their implications for warning verification and future changes in the NWS warning paradigm, such as “warning polygons” and probabilistic threat area warnings. We also consider improvements to the data collection methodologies and the expansion of the experiment in 2007 to include the analysis of severe wind events and other threats.

Available online at ://http://ams.confex.com/ams/pdfpapers/120091.pdf.

Smith, T. M., V. Lakshmanan, 2006: Utilizing Google Earth as a GIS platform for weather applications. Preprints, 22nd Conference on Interactive Information Processing Systems, Atlanta, GA, USA, AMS, CD-ROM, 8.2.

Available online at ://http://ams.confex.com/ams/Annual2006/techprogram/paper_104847.htm.

Smith, T. M., K. L. Ortega, K. A. Scharfenberg, K. M. Manross, A. Witt, 2006: The Severe Hail Verfication Experiment. Preprints, 23rd Conference on Severe Local Storms, St. Louis, MO, USA, AMS, CD-ROM, 5.3.

Available online at ://http://ams.confex.com/ams/23SLS/techprogram/paper_115436.htm.

Smith, T. M., G. J. Stumpf, 2005: Multi-sensor storm cell identification and analysis. Preprints, 21st International Conference on Interactive Information and Processing Systems (IIPS) for Meteorology, Oceanography, and Hydrology, San Diego, CA, USA, American Meteorological Society, P1.10.

Stumpf, G. J., T. M. Smith, D. L. Andra, D. W. Burgess, J. G. LaDue, L. R. Lemon, M. A. Magsig, K. Manross, D. J. Miller, S. Nelson, K. L. Ortega, K. Scharfenberg, D. W. Sharp, 2008: Experimental gridded warning guidance for severe convective weather threats. Extended Abstracts, 24th Conf. on IIPS, New Orleans, LA, USA, Amer. Meteor. Soc., P1.3.

Stumpf, G. J., T. M. Smith, K. Manross, D. L. Andra, 2008: The Experimental Warning Program 2008 Spring Experiment at the NOAA Hazardous Weather Testbed. Preprints, 24th Conference on Severe Local Storms, Savannah, GA, USA, American Meteorological Society, CD-ROM, 8A.1.

The NOAA Hazardous Weather Testbed's (HWT) Experimental Warning Program's (EWP) purpose is to integrate National Weather Service (NWS) operational meteorologists, and National Severe Storms Laboratory (NSSL) researchers to test new science, technologies, products, and services designed to improve short-term (0-2 hour) warnings and nowcasts of severe convective weather threats. The EWP conducted its second formal Spring Experiment during a six week period in 2008 at the National Weather Center in Norman, OK.

There were three primary projects geared toward WFO severe weather warning operations, 1) an evaluation of the rapidly-updating phased array radar (PAR) in Norman, 2) an evaluation of a high-density network of 3-cm radars (CASA) in Central Oklahoma, and 3) an evaluation of experimental high temporal and spatial resolution gridded hazard information (a.k.a. gridded probabilistic warnings). Twenty NWS forecasters representing five of the six NWS Regions participated in the experiment, along with personnel from the NWS Warning Decision Training Branch, several universities, and other federal and academic agencies.

Operational activities took place during the week Monday through Thursday, with an end-of-week summary debriefing taking place on Friday. Most days consisted of a 3-4 hour Intensive Operations Period (IOP) where the forecasters were immersed in evaluations of three experiment on live data in a simulated severe weather warning environment. When severe weather was occurring within Central Oklahoma, the PAR and CASA experiments were the primary focus. When storms were elsewhere in the CONUS, the gridded probabilistic warning experiment was conducted. Outside of the IOPs, the forecasters worked with cognizant scientists to review archive cases, sometimes in a simulated displace real-time setting. Feedback was obtained from the forecasters during live and archive playback operations through the use of written surveys, voice recording, and discussions which were summarized on the EWP Blog. Operations were facilitated via the use of a multi-LCD/plasma Situational Awareness Display.

Available online at ://http://ams.confex.com/ams/pdfpapers/141712.pdf.

Stumpf, G. J., M. T. Filiaggi, M. A. Magsig, K. D. Hondl, S. B. Smith, R. Toomey, C. Kerr, 2006: Status on the integration of the NSSL Four-dimensional Stormcell Investigator (FSI) into AWIPS. Preprints, 23rd Conference on Severe Local Storms, St. Louis, MO, USA, American Meteorological Society, CD-ROM, 8.3.

Stumpf, G. J., S. B. Smith, K. E. Kelleher, 2005: Collaborative activities of the NWS MDL and NSSL to improve and develop new severe weather warning guidance applications. Preprints, 21st International Conference on Interactive Information and Processing Systems (IIPS) for Meteorology, Oceanography, and Hydrology, San Diego, CA, USA, American Meteorological Society, P2.13.

Stumpf, G. J., K. D. Hondl, S. B. Smith, M. T. Filiaggi, V. Lakshmanan, 2005: Status on the four-dimensional base radar data analysis tool for AWIPS. Preprints, 32nd Conference on Radar Meteorology, Albuquerque, NM, USA, American Meteorological Society, CD-ROM, 8R.5.

Vasiloff, S. V., K. Howard, 2009: Investigation of a severe downburst storm near Phoenix, Arizona, as seen by a mobile Dopper radar and the KIWA WSR-88D. Weather and Forecasting, 24, 856-867.

Vasiloff, S. V., K. H. Howard, 2007: Investigation of a severe microburst near Phoenix, Arizona as seen by a mobile Doppler radar and the KIWA WSR-88D. Extended Abstracts, 13th Conference on Aviation, Range and Aerospace Meteorology, New Orleans, LA, USA, AMS, p4.7.

Vasiloff, S. V., B. Kaney, C. Langston, W. Xia, 2007: The National Severe Storms Laboratory QPE verification system. Extended Abstracts, 24th Conference on IIPS, New Orleans, LA, USA, AMS, 6B.12.

Vasiloff, S. V., D. J. Seo, K. W. Howard, J. Zhang, D. H. Kitzmiller, M. G. Mullusky, W. F. Krajewski, E. A. Brandes, R. M. Rabin, D. S. Berkowitz, H. E. Brooks, J. A. McGinley, R. J. Kuligowski, B. G. Brown, 2007: Improving QPE and Very Short Term QPF: An Initiative for a Community-Wide Integrated Approach. Bulletin of the American Meteorological Society, 88, 1899-1911.

Accurate quantitative precipitation estimates (QPE) and very short term quantitative precipitation forecasts (VSTQPF) are critical to accurate monitoring and prediction of water-related hazards and water resources. While tremendous progress has been made in the last quarter-century in many areas of QPE and VSTQPF, significant gaps continue to exist in both knowledge and capabilities that are necessary to produce accurate high-resolution precipitation estimates at the national scale for a wide spectrum of users. Toward this goal, a national next-generation QPE and VSTQPF (Q2) workshop was held in Norman, Oklahoma, on 28–30 June 2005. Scientists, operational forecasters, water managers, and stakeholders from public and private sectors, including academia, presented and discussed a broad range of precipitation and forecasting topics and issues, and developed a list of science focus areas. To meet the nation's needs for the precipitation information effectively, the authors herein propose a community-wide integrated approach for precipitation information that fully capitalizes on recent advances in science and technology, and leverages the wide range of expertise and experience that exists in the research and operational communities. The concepts and recommendations from the workshop form the Q2 science plan and a suggested path to operations. Implementation of these concepts is expected to improve river forecasts and flood and flash flood watches and warnings, and to enhance various hydrologic and hydrometeorological services for a wide range of users and customers. In support of this initiative, the National Mosaic and Q2 (NMQ) system is being developed at the National Severe Storms Laboratory to serve as a community test bed for QPE and VSTQPF research and to facilitate the transition to operations of research applications. The NMQ system provides a real-time, around-the-clock data infusion and applications development and evaluation environment, and thus offers a community-wide platform for development and testing of advances in the focus areas.

Vasiloff, S. V., 2006: Comparison of 2 hour forecasts based on persistence and a cross-correlation technique. Preprints, 12th Conference on Aviation, Range, and Aerospace Meteorology, Atlanta, GA, USA, AMS, CD-ROM, 3.10. [Available from steven.vasiloff@noaa.gov, National Weather Center, 120 David L. Boren Blvd., Norman, OK, USA, 73072.]

The NCAR Weather Support to Deicing Decision Making System (WSDDM) uses a cross-correlation technique to produce radar echo motion vectors. These vectors are then used to forecast snow water equivalent precipitation based on future echo positions with the focus on airports. It has been shown that WSDDM 30 min forecasts have large skill compared to persistence forecasts (a persistence forecast assumes that the current state will continue). This paper carries this type of comparative analysis out to two hours. Data from winter storms in the upper Midwest are evaluated and point forecasts near Chicago and Minneapolis are determined for both methods. Various echo configurations are used for the tests and include rain/snow bands, echoes from different sectors of synoptic cyclones and echoes with various reflectivity intensities.

Wicker, L. J., 2009: A two-step Adams-Bashforth-Moulton split-explicit integrator for compressible atmospheric models.. Monthly Weather Review, 137, 3588-3595.

Split-explicit integration methods used for the compressible Navier-Stokes equations are now used in a wide variety of numerical models ranging from high-resolution local models to convection-permitting climate simulations. Models are now including more sophisticated and complicated physical processes, such as multi-moment microphysics parameterizations, electrification, and dry/aqueous chemistry. A wider range of simulations problems combined with the increasing physics complexity may place a tighter constraint on the model's time step compared to the fluid flow's courant number, e.g., the choice of the integration time step based solely on advective courant number considerations may generate unacceptable errors associated from the parameterization schemes. The third-order multistage Runge-Kutta scheme has been very successful as the a split-explicit integration method, however, its efficiency arises partially in its ability to use a time step that is 20–40% larger than more traditional integration schemes. In applications where the time step is constrained by other considerations, alternative integration schemes may be more efficient. Here a two-step third-order Adams-Bashforth-Moulton integrator is stably split in a similar manner as the split Runge-Kutta scheme. For applications where the large time step is not constrained by the advective courant number it requires less computational effort. Stability is demonstrated through eigenvalue analysis of the linear coupled one-dimensional velocity-pressure equations, and full two-dimensional nonlinear solutions from a standard test problem are shown to demonstrate solution accuracy and efficiency.

Witt, A., R. A. Brown, Z. Jing, 2009: Performance of a new velocity dealiasing algorithm for the WSR-88D. Preprints, 34th Conference on Radar Meteorology, Williamsburg, VA, USA, AMS, P4.8.

Witt, A., 2007: Performance of two velocity dealiasing algorithms on Terminal Doppler Weather Radar data. Preprints, 33rd Conference on Radar Meteorology, Cairns, Australia, American Meteorological Society, CD-ROM, P13A.14.

Witt, A., R. A. Brown, V. Lakshmanan, 2005: Real-time calculation of horizontal winds using multiple Doppler radars: A new WDSS-II module. Preprints, 32nd Conference on Radar Meteorology, Albuquerque, NM, USA, Amer. Meteor. Soc., CD-ROM, P8R.7.

Wood, V. T., R. A. Brown, D. C. Dowell, 2009: Simulated WSR-88D Velocity and Reflectivity Signatures of Numerically Modeled Tornadoes. Journal of Atmospheric and Oceanic Technology, 26, 876-893.

Low-altitude radar reflectivity measurements of tornadoes sometimes reveal a donut-shaped signature (low-reflectivity eye surrounded by a high-reflectivity annulus) and at other times reveal a high-reflectivity knob associated with the tornado. The differences appear to be due to such factors as (i) the radar’s sampling resolution, (ii) the presence or absence of lofted debris and a low-reflectivity eye, (iii) whether measurements were made within the lowest few hundred meters where centrifuged hydrometeors and smaller debris particles were recycled back into the tornadic circulation, and (iv) the presence or absence of multiple vortices in the parent tornado.

To explore the influences of some of these various factors on radar reflectivity and Doppler velocity signatures, a high-resolution tornado numerical model was used that incorporated the centrifuging of hydrometeors. A model reflectivity field was computed from the resulting concentration of hydrometeors. Then, the model reflectivity and velocity fields were scanned by a simulated Weather Surveillance Radar-1988 Doppler (WSR-88D) using both the legacy resolution and the new super-resolution sampling. Super-resolution reflectivity and Doppler velocity data are displayed at 0.5° instead of 1.0° azimuthal sampling intervals and reflectivity data are displayed at 0.25-km instead of 1.0-km range intervals.

Since a mean Doppler velocity value is the reflectivity-weighted mean of the radial motion of all the radar scatterers within a radar beam, a nonuniform distribution of scatterers produces a different mean Doppler velocity value than does a uniform distribution of scatterers. Nonuniform reflectivities within the effective resolution volume of the radar beam can bias the indicated size and strength of the tornado’s core region within the radius of the peak tangential velocities. As shown in the simulation results, the Doppler-indicated radius of the peak wind underestimates the true radius and true peak tangential velocity when the effective beamwidth is less than the tornado’s core diameter and there is a weak-reflectivity eye at the center of the tornado. As the beam becomes significantly wider than the tornado’s core diameter with increasing range, the peaks of the Doppler velocity profiles continue to decrease in magnitude but overestimate the tornado’s true radius. With increasing range from the radar, the prominence of the weak-reflectivity eye at the center of the tornado is progressively lessened until it finally disappears. As to be expected, the Doppler velocity signatures and reflectivity eye signatures were more prominent and stronger with super-resolution sampling than those with legacy-resolution sampling.

Wood, V. T., L. W. White, 2009: A Skirted Rankine Combined Vortex Model. Extended Abstracts, 24th Conference on Severe Local Storms, Savannah, GA, USA, AMS, P3.4.

Wood, V. T., J. N. Chrisman, 2009: Impacts of the Automated Volume Scan Evaluation and Termination (AVSET) on the WSR-88D Velocity-Azimuth Display (VAD) Wind Profile (VWP). Extended Abstracts, 34th Conference on Radar Meteorology, Williamsburg, VA, USA, American Meteorological Society, P4.1.

Wood, V. T., 2009: Impacts of the automated volume scan evaluation and termination (AVSET) algorithm on the WSR-88D Velocity-Azimuth Display (VAD) Wind Profile (VWP). FY 2009 Memorandum of Understanding Between WSR-88D Radar Operations Center and National Severe Storms Laboratory Task 8.0, 81 pp.

Wood, V. T., 2008: Improvement of WSR-88D VAD Winds: Cyclonic Wind Fields. Preprints, 28th Conference on Hurricanes and Tropical Meteorology, Orlando, FL, USA, AMS, P2B.3. [Available from Vincent T. Wood, 120 David L. Boren Blvd., National Severe Storms Laboratory, Norman, OK, USA, 73072.]

Hurricanes pose a serious threat to life and property along the Gulf and Atlantic coastal regions of the United States. The WSR-88D network provides the potential to improve hurricane forecasts and warnings by monitoring changes in a hurricane’s track, eye diameter, radar eyewall and rainband reflectivities. The WSR-88D Velocity-Azimuth Display (VAD) Wind Profile (VWP) display is a useful tool for diagnosis of wind fields at different altitudes as a hurricane is approaching a coastal WSR-88D.

The causes of missing winds on the VWP display were related to cyclonic flow from the approaching hurricane. The missing data arose because the extreme positive and negative Doppler velocity values around the VAD circle were inherently not 180 degrees apart and, therefore, the first-harmonic Fourier sine curve used in the operational WSR-88D VAD algorithm was a poor fit to the data. This resulted in root-mean-square (RMS) differences that exceeded the threshold value. In this situation, most of the winds on the VWP display were set equal to missing in spite of the fact that there were strong radar returns.

A new solution to recover or improve VAD winds has been developed. A higher-order polynomial regression technique employs least-squares fit of the Doppler velocity data distributed on the VAD circle. Wind speed is computed from the average of the magnitudes of the positive and negative peaks of the quasi-sine curve. Wind direction is determined from the average of the magnitudes of maximum and minimum azimuths (at which positive and negative Doppler velocity peaks occur, respectively) minus ninety degrees. After applying the experimental technique to a couple of hurricane cases such as Hurricane Katrina (29 August 2005) and Hurricane Rita (20 September 2005), the technique examines a standard deviation about a regression line which agrees well with the RMS value. The higher-order polynomial regression VAD curve fits the measurements with low RMS difference values. It is indicated that the technique does a good job of fitting the curve to the data points with low RMS difference between the curve and data points.

Wood, V. T., L. W. White, 2008: A Skirted Rankine Combined Vortex Model. Extended Abstracts, 24th Conference on Severe Local Storms, Savannah, GA, USA, American Meteorological Society, P3.4.

Wood, V. T., 2008: Need for Potential VAD Improvements. Final Report, FY2008 Memorandom of Understanding Between WSR-88D Radar Operations Center and National Severe Storms Laboratory Task No. 8.1, 76 pp.

Wood, V. T., 2007: OK-WARN: Oklahoma Weather Alert Remote Notification. Preprints, 16th Symposium on Education, San Antonio, TX, USA, Amer. Meteor. Soc., CD-ROM P1.25.

Oklahoma Weather Alert Remote Notification (OK-WARN) is a new service that provides timely notification of weather hazards and emergencies to people with hearing loss via pager, e-mail or cell phone. This program was developed as a partnership between Oklahoma Department of Emergency Management, NOAA National Weather Service, NOAA National Severe Storms Laboratory, Oklahoma Department of Rehabilitation Services, Communication Services for the Deaf of Oklahoma, and Weather Affirmation, LLC. OK-WARN was made possible by a federal grant from the Federal Emergency Management Agency, now a division of the Department of Homeland Security. Since the inception of OK-WARN in 2001, the program has been expanded statewide to serve the deaf and hard-of-hearing community. Information about how OK-WARN operates will be presented.

Wood, V. T., 2007: Impact of Severe Weather on People with Hearing Loss. Weather and Society Watch Vol. 1, No. 4, July 20, 2007, 3 pp.

Wood, V. T., 2007: Improvement of WSR-88D VAD Winds: Cyclonic Wind Fields. Final Report, FY2007 Memorandum of Understanding Between WSR-88D Radar Operations Center and National Severe Storms Laboratory Task 5, 41 pp.

Wood, V. T., L. W. White, C. R. Alexander, R. L. Tanamachi, 2006: An analytical model of one- and two-celled vortices: Preliminary testing. Preprints, 23rd Conference on Severe Local Storms, St. Louis, MO, USA, American Meteorological Society, CD-ROM, P10.1.

Wood, V. T., R. A. Brown, D. C. Dowell, 2005: Simulated WSR-88D measurements of low-reflectivity eyes associated with tornadoes. 32nd Conference on Radar Meteorology, Albuquerque, NM, USA, American Meteorological Society, CD-ROM, P15R.6.

Zhang, J., K. Howard, S. Vasiloff, C. Langston, B. Kaney, A. Arthur, S. Van Cooten, K. Kelleher, D. Kitzmiller, F. Ding, D. J. Seo, M. Mullusky, E. Wells, T. Schneider, C. Dempsey, 2009: National Mosaic and multi-sensor QPE (NMQ) system: description, results and future plans. Preprints, The 34th Conference on Radar meteorology, Williamsburg, VA, USA, American Meteorological Society, 7A.1.

Zhang, J., Y. Qi, 2009: Correction of bright band effects in radar observations from plain areas. Preprints, The 34th Conf. on Radar Meteorology, Williamsburg, VA, USA, American Meteorological Society, P14.5.

Zhang, J., K. Howard, X. Xu, 2008: A warm season radar QPE algorithm using adaptive Z-R relationships. Proc. World Environmental and Water Resources Congress 2008, Honolulu, HI, USA, Amer. Soc. Civil Engineers, CD-ROM, 420.pdf.

Zhang, J., C. Langston, K. Howard, 2008: Three-dimensional radar mosaic integrating WSR-88Ds and Canadian radar network. Preprints, The 13th Conf. on Aviation, Range, and Aerospace Meteorology, New Orleans, LA, USA, Amer. Meteor. Soc., CD-ROM, P4.4.

Zhang, J., C. Langston, K. Howard, 2008: Bright Band Identification Based On Vertical Profiles of Reflectivity from the WSR-88D. Journal of Atmospheric and Oceanic Technology, 25, 1859-1872.

Zhang, J., K. Howard, P. L. Chang, P. T. Chiu, C. R. Chen, C. Langston, W. Xia, B. Kaney, P. F. Lin, 2008: High-Resolution QPE System for Taiwan. Data Assimilation for Atmospheric, Oceanic, and Hydrologic Applications, S. K. Park, L. Xu, Ed(s)., Springer-Verlag, 145-160.

Zhang, J., C. Langston, K. Howard, 2007: Brightband identification from vertical profile of reflectivity. Preprints, The 33rd International Conf. on Radar Meteorology, Cairns, Australia, Amer. Meteor. Soc., P8A.13.

Zhang, J., S. Wang, 2006: An Automated 2D Multipass Doppler Radar Volocity Dealiasing Scheme. Journal of Atmospheric and Oceanic Technology, 23, 1239-1248.

Zhang, J., C. Langston, K. Howard, 2006: Vertical profiles of reflectivity for different precipitation regimes. Proc. The 4th European Conference on Radar in Meteorology and Hydrology, Barcelona, Spain, Servei Meteorologic de Catalunya, 225-228.

Zhang, J., K. Howard, S. Wang, 2006: Single radar Cartesian grid and adaptive radar mosaic system. Preprints, The 12th Conference on Aviation, Range, and Aerospace Meteorolog, Atlanta, GA, USA, Amer. Meteor. Soc., 1.8.

Zhang, J., C. Langston, K. Howard, B. Clarke, 2006: Gap-filling in 3D radar mosaic analysis using vertical profile of reflectivity. Preprints, The 12th Conference on Aviation, Range, and Aerospace Meteorology, Atlanta, GA, USA, Amer. Meteor. Soc., CD-ROM, P1.9.

Zhang, J., K. Howard, J. J. Gourley, 2005: Constructing three-dimensional multiple radar reflectivity mosaics: examples of convective storms and stratiform rain echoes. Journal of Atmospheric and Oceanic Technology, 22, 30-42.