(1/25/06): On pp. 3574-3575, Bond et al. (2006) describes possible CSI, although using terminology inconsistent with Schultz and Schumacher (1999). Nevertheless, they make some intriguing comments about the nature of such circulations. Bond, N. A., B. F. Smull, M. T. Stoelinga, C. P. Woods, and A. Haase, 2005: Evolution of a cold front encountering steep quasi-2D terrain: Coordinated aircraft observations on 8-9 December 2001 during IMPROVE-2. J. Atmos. Sci., 62, 3559-3579.

(1/22/06): Mantovani and Speranza (2002): Baroclinic instability of a symmetric rotating, stratified flow: A study of the nonlinear stabilisation mechanisms in the presence of viscosity. Nonlinear Processes in Geophysics, 9, 487-496. [Available online].

(12/29/05): Schultz, D. M., 2006: Comments on "Cloud-resolving model simulations of multiply-banded frontal clouds" by Pizzamei et al. (2005). Quarterly J. Royal Meteor. Soc., submitted. [Available online at http://www.cimms.ou.edu/~schultz/papers/pizzameicomments.pdf] [PDF]

(12/29/05): Pizzamei, M., S. L. Gray, and K. A. Browning, 2005: Cloud-resolving model simulations of multiply-banded frontal clouds. Q. J. R. Meteorol. Soc., 131, 2617-2637.

(10/31/05): Qin Xu presented "Non-modal growths of symmetric perturbations produced by paired normal modes" at the 11th Mesoscale Conference in Albuquerque. You can download a preprint here.

(3/25/05): Peter R. Bannon. 2004: Lagrangian Available Energetics and Parcel Instabilities. Journal of the Atmospheric Sciences: Vol. 61, No. 14, pp. 1754-1767.

(1/4/05): The December 2004 issue of Weather and Forecasting has two articles on banded precipitation.

• Novak, D. R., L. F. Bosart, D. Keyser, and J. S. Waldstreicher, 2004: An observational study of cold season-banded precipitation in northeast U.S. cyclones. Wea. Forecasting, 19, 993-1010.
  
• Jurewicz, M. L., and M. S. Evans, 2004: A comparison of two banded, heavy snowstorms with very different synoptic settings. Wea. Forecasting, 19, 1011-1028.

(8/3/04): Brian Colle published a study of Hurricane Floyd showing how frontogenesis in the presence of near-neutral symmetric stability produced the heavy rains. Check out: "Numerical simulations of the extratropical transition of Floyd (1999): Structural evolution and responsible mechanisms for the heavy rainfall over the northeast United States." Mon. Wea. Rev., 131, 2905-2926 (December 2003 issue).

(5/26/04): Two new papers by Qin Xu: "Nearly symmetric and nearly baroclinic instabilities in the presence of diffusivity. Part 1. Growth rate patterns." J. Fluid Mech., 492, 181-205. and "Part 2. Mode structures and energetics." J. Fluid Mech., 500, 283-312. Part 2 provides a nice explanation for why bands growing in a symmetrically unstable environment may not lie parallel to the thickness contours.

(3/31/04): Mathur, Mukut B., Brill, Keith F., Seman, Charles J. 1999: Evolution of Slantwise Vertical Motions in NCEP's Mesoscale Eta Model. Monthly Weather Review: Vol. 127, No. 1, pp. 5-25.

(3/31/04): I neglected to post this paper that was published in Atmospheric Science Letters, the Royal Meteorological Society's online journal: Dixon, Browning, and Shutts, 2000: The mystery of striated cloud heads in satellite imagery. Atmospheric Science Letters, doi:10.1006/asle.2000.0001. Grab a PDF here.

(12/16/02): "A Reexamination of the Mechanisms Responsible for Banded Precipitation" by Clark et al. is published in the December 2002 issue of Monthly Weather Review.

(7/31/02): "Formation of a Sharp Snow Gradient in a Midwestern Heavy Snow Event" by Market and Cissell is published in the August 2002 issue of Weather and Forecasting.

(7/31/02): Dave Novak's Banding Cases

(7/8/02): Coleman and Marwitz, 2002: "Thermodynamic and kinematic structure of a snowband and freezing rain event during STORM-FEST" (February 2002 Weather and Forecasting, 17, 27-46.) argue that you should examine the saturation with respect to ice (in the case of frozen precipitation) before assessing CSI or CI.

(6/14/02): A talk will be presented at the Weather and Forecasting Conference in San Antonio entitled, "A Climatological and Composite Study of Cold Season Banded Precipitation in the Northeast United States" by Novak et al. I highly recommend this paper because it is the type of research that needs to be done in order to illuminate the forcing mechanisms and the frequency of MSI in observed cases. Here is the abstract from the AMS web page.

(5/20/02): Just published: Scott Braun, 2002: A cloud-resolving simulation of Hurricane Bob (1991): Storm structure and eyewall buoyancy. MWR, 130, 1573-1592.

(5/2/02): Just published: Richard Dixon and Keith Browning, 2002: The relation of moist symmetric instability and upper-level potential-vorticity anomalies to the observed evolution of cloud heads. QJRMS, 128, 839-859.

(4/27/02): Browning and Wang (2002): Cloud-top striations above ana-cold frontal circulations. QJRMS, 128, 477-499.

(4/1/02): I updated the reference list to include new articles that have been published since Schultz and Schumacher (1999).

(3/29/02): Lemaître, Y., G. Scialom, and A. Protat, 2001: Conditional symmetric instability, frontogenetic forcing and rain-band organization. Quart. J. Roy. Meteor. Soc., 127, 2599-2634.

(11/20/01):"Potential Vorticity in a Moist Atmosphere" by Schubert et al. is published in the 1 November 2001 issue of Journal of Atmospheric Sciences, pages 3148-3157.

(7/9/01):"Parcel theory in three dimensions and the calculation of SCAPE" by Sue Gray and Alan Thorpe is published in the July 2001 issue of Monthly Weather Review. Email Sue Gray for a copy.

(7/5/01):"Nonlinear viscous symmetric circulations: The physical mechanisms of stabilisation" by Roberta Mantovani and Antonio Speranza has been submitted to the Quarterly Journal of the Royal Meteorological Society. Email Antonio Speranza for a copy.

(5/22/01): Scripts for computing MPVg* in AWIPS are now available on Dan Baumgardt's Volume Browser homepage (http://www.crh.noaa.gov/arx/vb/index.htm). See Calculating CSI for more information.

(5/16/01): In response to an apparent confusion over the meaning of the term saturation equivalent potential temperature, we have updated the FAQ.

(5/8/01): "Stacked slantwise convective circulations" by Browning, Chapman, and Dixon has been submitted to Quarterly Journal of the Royal Meteorological Society.

(5/1/01): Sue Gray and Alan Thorpe (University of Reading) published "Potential energy for slantwise parcel motion" in the new on-line Royal Meteorological Society journal, Atmospheric Science Letters. [Download a PDF of Gray and Thorpe (2001).]

(4/12/01): Comments on Wetzel and Martin's "An operational ingredients-based methodology for forecasting midlatitude winter season precipitation" have been submitted by Schultz, Cortinas, and Doswell.

(3/14/01):"An operational ingredients-based methodology for forecasting midlatitude winter season precipitation" expands on the methodology suggested by Schultz and Schumacher (1999). [Wetzel, S. W., and J. E. Martin, 2001: An Operational Ingredients-Based Methodology for Forecasting Midlatitude Winter Season Precipitation. Weather and Forecasting, 16, 156-167.]

(12/26/00):"The mystery of striated cloud heads in satellite imagery" (Dixon et al. 2000) explores the possibility of CSI playing a role in striated cloud heads seen on satellite imagery.

(9/27/00):"Dynamical effects of ice sublimation in a frontal wave" by Clough et al. appeared in Quarterly Journal of the Royal Meteorological Society. Besides being a nice demonstration of the effects of snow sublimation on frontal circulations and the generation of negative potential vorticity, Clough et al. (2000) also provides an interesting perspective on the role for CSI in such circulations.

Clough, S. A., H. W. Lean, N. M. Roberts, and R. M. Forbes, 2000: Dynamical effects of ice sublimation in a frontal wave. Quart. J. Roy. Meteor. Soc., 126, 2405-2434.

(7/5/00):"A Reexamination of the Mechanisms Responsible for Banded Precipitation" by John Clark, Richard James, and Richard Grumm has been submitted to Monthly Weather Review. For a copy, email clark@ems.psu.edu.

(6/8/00): Rich Dixon's Ph.D. Dissertation from the University of Reading: "Diagnostic Studies of Symmetric Instability".

(5/22/00):A Corrigendum for Schultz and Schumacher (1999) has been published in the May 2000 issue of Monthly Weather Review. Get a copy in PDF format. The correct way to reference our paper is now:

Schultz, D. M., and P. N. Schumacher, 1999: The use and misuse of conditional symmetric instability. Mon. Wea. Rev., 127, 2709-2732; Corrigendum, 128, 1573.

(3/20/00): Sue Gray and Alan Thorpe (University of Reading) have recently submitted two manuscripts on SCAPE for publication. Email her at sws98slg@met.reading.ac.uk for copies.

The first is entitled "Potential energy for slantwise parcel motion" and is a comparison between the derivations for SCAPE and the expression for the energy of slantwise motion derived by Green, Ludlam and McIlveen (1966). It's been submitted to the new on-line Royal Meteorological Society journal, Atmospheric Science Letters.

The second is entitled "Parcel theory in three dimensions and the calculation of SCAPE." In this paper, an approximate extension of the parcel theory for CSI is derived for three dimensions. SCAPE along trajectories calculated using the 2D theory is compared with SCAPE along trajectories calculated using the 3D theory. The results are very different, which suggests that the assumption implicit in the 2D theory, that the rate of system development is slow in comparison with the slantwise ascent rate, is a poor one. This has been submitted to Monthly Weather Review.

(3/8/00): A Postscript file for "On moist instability," Correspondence submitted to Monthly Weather Review by Steve Sherwood (Universities Space Research Association, Seabrook, Maryland). Steve raises some very intriguing issues with how we as atmospheric scientists deal with the terminology "conditional instability" and "conditional symmetric instability."

(1/14/00): A Corel Presentations File for talk given by Phil Schumacher at the Eastern Region SOO Conference.

(12/11/99): I have updated the reference list to include papers that have been published since Schultz and Schumacher (1999) was accepted in its final form.

(11/30/99): We now have a FAQ (Frequently Asked Questions) page.

(11/19/99): A COMET Webcast of our presentation "The Use and Misuse of CSI" can be found at http://meted.ucar.edu/export/csi/. More information can be found here.

(11/18/99): Our manuscript is now available at American Meteorological Society Journals Online.

(10/8/99): Watch for publication of our manuscript in the December 1999 issue of Monthly Weather Review (pp. 2709-2732).

(8/25/99): The page proofs of our manuscript have been submitted.

(7/9/99): Here is a link to some current work by Richard Dixon at Reading University. He uses a CSI parameter to locate areas in the 50-km U.K. Limited Area Model where symmetric instability is likely. He will be presenting this work at the IUGG in Birmingham.

(7/7/99): A great new article on frontal circulations in the presence of CSI can be found in the June 1999 issue of Weather and Forecasting: Nicosia and Grumm (1999): Mesoscale band formation in three major northeastern United States snowstorms, pp. 346-368.

(3/20/99): 09 March 1999 -- Heavy Snow Over the Mid-Atlantic Region: A CSI Perspective: A web-based discussion by Scott Bachmeier and David Schultz

(2/26/99): Mesoscale Processes Conference preprint, available on-line
HTML version
Postscript version
(12/28/98): Our manuscript has now been accepted for publication. Thanks to everyone who contributed comments!
Click here to obtain a postscript version of this manuscript (text only).
Click here to view an HTML version of the manuscript (includes figures).