VORTEX SE: Supported Research 2017

Addressing Risk Awareness and Response, and Tornado Damage Mitigation

Convective mode and Tennessee tornadoes: Climatology, warning procedures, and false alarm rates

Lead investigators: Elis and Mason, University of Tennessee

Goal: This work will use quantitative and qualitative analyses to assess the role of convective mode on risk and vulnerability to Tennessee tornadoes. Specifically, we will determine the role of convective mode on the tornado climatology, NWS warning procedures, and false alarm rates in Tennessee.

Understanding how uncertainty in severe weather information affects decisions

Lead investigators: LaDue and Friedman, University of Oklahoma; Myers, University of Alabama

Goal: This project studies how National Weather Service forecasters, broadcast meteorologists, emergency managers (EMs), and publics in the 2017 VORTEX-SE domain interpret, communicate, and make decisions under the uncertainty associated with difficult to forecast tornadoes and associated severe weather events. The outcomes of this research will be immediately applicable to NOAA's mission to focus and prioritize research and development efforts to alleviate challenges in forecasting, warning, and communicating about severe weather.

Addressing interconnections between the built and natural environments through post-event damage surveys

Lead investigators: Lombardo, University of Illinois; Godfrey, University of North Carolina at Asheville; Peterson, University of Georgia

Goal: Characterize the levels of debris and damage related to the interconnectedness of the built (e.g., buildings) and natural (e.g., terrain, trees) environment. This characterization will be carried out through detailed post-event damage surveys. Results from the surveys will then be employed in simulations to recreate the near-surface wind, debris and damage fields.

Lay judgments of environmental cues that signal a tornado

Lead investigators: Broomell and Wong-Parodi, Carnegie Mellon

Goal: Analyze the efficacy of the public's perception of tornado danger based on the immediate environment in the southeastern U.S. by comparing their perceptions to expert descriptions of useful environmental signals of danger. This work will lead to more effective communication and education efforts in the southeast aimed at improving decisions to take shelter.

Improving risk communication and reducing vulnerabilities for dynamic tornado threats in the southeastern U.S.

Lead investigators: Demuth, NCAR; Anderson, University of Colorado; Henderson, Virginia Tech

Goal: With a goal of helping improve tornado forecast and warning communication and response, this project will develop new knowledge about (a) how people’s risk perceptions and responses evolve dynamically with a tornado threat; and (b) how these interact with evolving risk information and vulnerabilities for tornado events in the southeastern US. It will do so through content analysis of Twitter data, follow-up telephone interviews with selected Twitterers, and in-person interviews with vulnerable members of the public.

Understanding how uncertainty in severe weather information affects decisions

Lead investigators: LaDue and Friedman, University of Oklahoma; Myers, University of Alabama

Goal: This project studies how National Weather Service forecasters, broadcast meteorologists, emergency managers (EMs), and publics in the 2017 VORTEX-SE domain interpret, communicate, and make decisions under the uncertainty associated with difficult to forecast tornadoes and associated severe weather events. The outcomes of this research will be immediately applicable to NOAA's mission to focus and prioritize research and development efforts to alleviate challenges in forecasting, warning, and communicating about severe weather.

Observing and Modelling Tornadic Storms and their Environments

Characterization of environmental influences on downdraft processes occurring in potentially tornadic storms in the Southeast United States

Lead investigators: Wurman, Marquis, Kosiba, Center for Severe Weather Research

Goal: This research will utilize a variety of observing systems to characterize the kinematic and thermodynamic variability of the environment ahead of potentially tornadic storms and investigate how the interactions between the near-storm environment and storm outflow contribute to tornadogenesis and evolution over the complex terrain of the Southeast U.S.

Improved understanding of tornado development and risk using models and observations from VORTEX-SE 2017

Lead investigators: Dawson, Tanamachi, Baldwin, Chavas, Purdue University; Frasier, University of Massachusetts

Goal: This project will combine a variety of tools to examine tornado problems of special interest in the southeastern U.S. Field components will include mobile upper air soundings, mobile observations of precipitation particles at the surface and aloft with two different radar systems, and portable surface probes equipped with laser disdrometers. A parallel emphasis on modeling will include real-data-driven numerical simulations of southeastern U.S. tornado cases, and statistical risk modeling to associate atmospheric conditions and local terrain gradients with the risk of tornadoes, both of which will emphasize cool-season events.

Understanding the variability of southeastern severe storm environments using mobile soundings during VORTEX-SE

Lead investigators: Brown, Mississippi State; Wade, University of Alabama Huntsville; Murphy, University of Louisiana Monroe

Goal: This project will deploy six mobile sounding systems in VORTEX-SE to assess the regional variability of severe weather forecast parameters such as CAPE and shear, as well as document the role of terrain and land use patterns in influencing these parameters and generating local boundaries of importance in modulating tornado potential.

Analysis and modeling of topographic influences on the atmospheric boundary layer: potential impact on tornado evolution

Lead investigators: Knupp and Mecikalski, University of Alabama Huntsville

Goal: This project will investigate the mesoscale variation of atmospheric boundary layer (ABL) flows modified by topography, which are hypothesized to influence tornadogenesis and/or tornado evolution over northern Alabama. The surface features unique to this region, relative to the Great Plains, include more significant topography, greater surface roughness, generally lower cloud base, and often low-CAPE/high-shear conditions. During this one-year project we will investigate variations in atmospheric flow and CAPE around Sand Mountain, including the Sand Mountain plateau and adjacent valley regions.

A numerical modeling approach to understanding the influence of terrain, land surface, and boundary layer heterogeneity on tornadic storm development

Lead investigators: Buban, Lee, Meyers, NOAA/OAR/ARL/ATDD, Oak Ridge, Tennessee

Goal: Data collected will be used to initialize and evaluate high-resolution numerical simulations. The goal of this study is to understand the small-scale features, particularly those caused or modified by differences in land surface characteristics that produce features such as NCMCs and regions of enhanced vorticity that can influence CI and severe thunderstorm evolution.

Improving understanding and prediction of concurrent tornadoes and flash floods with numerical models and VORTEX-SE observations

Lead investigators: Schumacher, Colorado State

Goal: This project will focus on situations when tornadoes and flash floods threaten the same area at the same time, abbreviated “TORFF” events, which are most frequent in the southeastern US. We will expand on our previous research on this topic by collecting and analyzing field observations of boundary-layer winds, thermodynamics, and precipitation structures in both tornado-only and TORFF situations to reveal important physical processes and environmental sensitivities; using numerical model experiments to quantify the influence of boundary-layer wind shear and thermodynamics on rainfall production in supercell storms and vortices embedded in convective lines; and continuing analysis of the NWS warning process during multi-hazard events by documenting the unique challenges in these events.

The role and predictability of baroclinic and terrain influences in southeastern U.S. tornado environments

Lead investigators: Weiss, Dahl, Bruning, Texas Tech; Dowell and Alexander, NOAA/OAR/ESRL; Schultz, NASA Earth Science Office

Goal: A multi-faceted effort will be undertaken to better understand the mechanisms controlling the genesis and maintenance of tornadoes in the southeastern United States. The study will use intensive observations at the surface and aloft, the integration of these observations into high- resolution numerical models, and controlled treatment of terrain effects on simulated tornadic storms.

Four-dimensional variability of southeastern storm environments, with and without terrain

Lead investigators: Parker, North Carolina State

Goal: Use idealized simulations of convective storms in observed VORTEX-SE environments in order to understand how within-storm processes differ from case to case, and between Plains (VORTEX2) and SE storm environments. Use case study simulations of observed VORTEX-SE cases in order to understand the interplay between stability and shear in various PBL schemes within an NWP model, and to understand the possible roles of terrain on the regional storm environment. These results will provide forecasters with a clearer idea of the magnitudes and temporal-spatial scales of variability in SE severe weather environments, including their similarities to and differences from Plains tornado environments.

Elucidating tornado precursors in quasi-linear convective storms with polarimetric radar

Lead investigators: Kumjian, Penn State

Goal: Exploit new dual-polarization radar information to anticipate tornadic nonsupercellular storms. This work will lead to an improved understanding and quantification of radar signatures preceding tornado formation, which can improve tornado warning lead times.