Lay Judgments of Environmental Cues that Signal a Tornado
S. Broomell, G. Wong-Parodie (Carnegie Mellon Univ.)
Outcomes:
- Progress: Surveys complete, data being analyzed and reports generated.
Formal publications and reports (None)
Project in progress under no-cost extension July 2019
updated 2019-07-15
Collaborative Research: Understanding How Uncertainty in Severe Weather Information Affects Decisions
D. LaDue, J. Friedman (Univ. Oklahoma); L. Myers (Univ. Alabama)
Outcomes:
- “…this project identified a number of discrete uncertainties that affect the decision making of both NWS WFO forecasters and Emergency Managers.”
- created a “Brief Vulnerability Overview Tool (BVOT) that would provide NWS WFO forecasters with a shapefile that they could use as a layer in AWIPS to remain aware of discrete, spatially-specific vulnerabilities across their CWA.”
- “… currently moving from an alpha-version to a beta-version of the BVOT after having piloted it in the study WFO and receiving feedback on its effectiveness and usability.”
- Numerous uncertainty-related findings based on survey work. [ER link to LM summary here]
- Manuscripts in progress
Formal publications and reports (None; 33 additional informal publications and presentations)
(See Community Forum blog post from Laura Myers related to this work. [ENR add link to blog])
Project completed December 2018 (Myers component); in progress under no-cost extension (LaDue/Friedman component) July 2019
updated 2019-07-15
Addressing Interconnections between the Built and Natural Environments through Post-Event Damage Surveys
F. Lombardo (Univ. Illinois); C. Godfrey (Univ. N. Carolina Asheville); C. Peterson (Univ. Georgia)
Outcomes:
- “…have further refined and developed a platform to simulate both trees and structures subjected to a tornado. This model will be an essential tool for generating theoretical debris distribution patterns for comparison with the actual debris distributions that the PIs have documented.”
- “…tornado vortex model coupled with a tree stability model merged with infrastructure fragility simulations … uses a theoretical placement of trees and structures in order to study the propagation of debris.”
Formal publications and reports (12 additional informal publications)
Cannon, J. B., J. Hepinstall-Cymerman, C. M. Godfrey, and C. J. Peterson, 2016: Landscape-scale patterns of forest tornado damage in mountainous terrain. Landscape Ecol., 31, 2097–2114,
https://doi.org/10.1007/s10980-016-0384-8. *
Godfrey, C. M., and C. J. Peterson, 2017: Estimating enhanced Fujita scale levels based on forest damage severity. Wea. Forecasting, 32, 243–252, https://doi.org/10.1175/WAF-D-16-0104.1. *
Roueche, D. B., Lombardo, F. T., & Prevatt, D. O. (2017). Empirical approach to evaluating the tornado fragility of residential structures. Journal of Structural Engineering, 143(9), https://doi.org/10.1061/(ASCE)ST.1943-541X.0001854 *
Rhee, D.M. and Lombardo, F.T., 2018:. Improved near-surface wind field characterization using damage patterns. J. Wind Engineering Industrial Aerodynamics 180: 288-297, https://doi.org/10.1016/j.jweia.2018.07.017
Zenoble, M., and C. J. Peterson, 2017: Damage path width and discontinuity in 50 tornado tracks through forested landscapes. Electronic J. Severe Storms Meteor., 12, 1 (download) *.
* also attributable to 2015 VORTEX-SE grant
Project completed December 2018
updated 2019-07-15
A Numerical Modeling Approach to Understanding the Influence of Terrain, Land Surface, and Boundary Layer Heterogeneity on Tornadic Storm Development
M. Buban (U. Maryland)
Outcomes:
- Observations obtained from two 10-m flux towers in the 2017 VORTEX-SE field campaign.
- Observations from a total of 25 UAS flights, using two different aircraft, obtained in 2018 campaign. In addition, 55 balloon soundings were obtained.
- COMMAS used to examine character of nonclassical mesoscale circulations as a function of land use heterogeneity.
Formal publications and reports (4 informal publications)
Lee, T.R., M. Buban, E. Dumas, and C.B. Baker, 2017: A New Technique to Estimate Sensible Heat Fluxes around Micrometeorological Towers Using Small Unmanned Aircraft Systems. J. Atmos. Oceanic Technol., 34, 2103–2112, https://doi.org/10.1175/JTECH-D-17-0065.1
Lee, T.R., M. Buban, D.D. Turner, T.P. Meyers, and C.B. Baker, 2019: Evaluation of the High-Resolution Rapid Refresh (HRRR) Model Using Near-Surface Meteorological and Flux Observations from Northern Alabama. Wea. Forecasting, 34, 635–663, https://doi.org/10.1175/WAF-D-18-0184.1 *
* also attributed to the 2015 grant above
Project completed December 2017
updated 2019-07-15
Elucidating Tornado Precursors in Quasi-Linear Convective Storms with Polarimetric Radar
M. Kumjian (Penn State Univ.)
Outcomes:
- “We have identified three repeatable signatures in tornadic QLCSs prior to tornadogenesis. These include (i) a separation of the enhanced Z DR and K DP regions at low levels, (ii) fallout of
enhanced K DP , indicative of a burst of precipitation, and (iii) a storm-relative rearward shift of the enhanced K DP region.” - Developed a detection algorithm based on the signatures.
Formal publications and reports (10 informal publications and presentations)
Loeffler, S.D. and M.R. Kumjian, 2018: Quantifying the Separation of Enhanced ZDR and KDP Regions in Nonsupercell Tornadic Storms. Wea. Forecasting, 33, 1143–1157, https://doi.org/10.1175/WAF-D-18-0011.1
Project completed December 2018
updated 2019-07-16
VORTEX-SE: The Role and Predictability of Baroclinic and Terrain Influences in Southeastern U.S. Tornado Environments
C. Weiss, E. Bruning, J. Dahl (Texas Tech Univ.); D. Dowell, C. Alexander (NOAA/ESRL); C. Schultz (NASA Marshall)
Outcomes:
- Suite of terrain/no-terrain WRF simulations underway to assess the role of terrain in modulating potentially tornadic convection in the Southeast.
- Tentative finding: “results suggest that the direct effect of the terrain on the thermodynamic and kinematic fields (and thus, overall storm behavior) is rather insignificant, it is possible that there are significant differences at the scale of individual cells.”
- An observed QLCS from 2017 showed sharper virtual potential temperature gradients, and higher inflow virtual potential overall, along segments that were (weakly) tornadic, compared to elsewhere.
Formal publications and reports (None; 7 informal publications)
Project in progress under no-cost extension July 2019
updated 2019-07-16
VORTEX-SE: Characterization of environmental influences on downdraft processes occurring in potentially tornadic storms in the Southeast United States
J. Wurman, K. Kosiba, J. Marquis (Center for Severe Weather Research)
Outcomes:
- Radar siting problems in northern Alabama resulting in lower-resolution analyses than desired.
- “…it is likely that the true heterogeneity of the atmosphere upstream of the downdraft region is under sampled by the relatively small network of soundings launched in this case.”
- “…analysis showed possibly considerable sensitivity of the retrieved dual-Doppler 3D winds aloft to the inclusion of wind observations at the ground, which affected the lower boundary condition in the wind synthesis… any future field observations from this area will have to take strongly into account that the limited radar sites should be accompanied by a larger density of surface observations needed to help offset such errors.”
- “Our recommendations suggest that more careful consideration of radar siting will be required for future observation phases in the Huntsville, AL area; also, that a larger profiling and surface station density is needed to accomplish similar science goals.”
Formal publications and reports (None; 7 informal publications)
Project completed December 2018
updated 2019-07-16
Improving Understanding and Prediction of Concurrent Tornadoes and Flash Floods With Numerical Models and VORTEX-SE Observations
R. Schumacher (Colorado State Univ.)
Outcomes:
- “…extended our analysis of overlapping TORFF warnings in the southeast through September 2018 (Figs. 1-2). The most striking aspect of this analysis was the importance of overlapping tornado and flash-flood threats in the landfalling tropical cyclones that affected the US in the fall of 2017.”
- “…environments with very strong low-level wind shear can promote extreme rainfall production in addition to the threat for tornadoes. This comes about through both increased low-level inflow and enhancement of updrafts through dynamic pressure effects.”
- 5 April 2017 (High Risk day) “soundings showed progressive drying, along with strengthening winds aloft over the course of the day (Fig. 4-5), which may have been important in limiting the development of deep convection that day.”
- “…it was shown that the SPC outlooks had highest skill for severe winds and lowest skill for tornadoes, but for significant severe reports the opposite was true (significant tornadoes had the highest
skill, with little skill for significant severe winds). The study also showed the spatial distribution of skill, and that forecasts struggled in high shear/low CAPE environments (common to the southeast) but also in very low-shear environments.”
Formal publications and reports (11 informal publications and presentations)
Herman, G.R., E.R. Nielsen, and R.S. Schumacher, 2018: Probabilistic Verification of Storm Prediction Center Convective Outlooks. Wea. Forecasting, 33, 161–184, https://doi.org/10.1175/WAF-D-17-0104.1
Childs, S.J., and R.S. Schumacher, 2018: Cold-season tornado risk communication: Case studies from November 2016 – February 2017. Weather, Climate, and Society, 10, 419– 433. https://doi.org/10.1175/WCAS-D-17-0073.1 *
Childs, S.J., R.S. Schumacher, and J.T. Allen, 2018: Cold-season tornadoes: Climatological and meteorological insights. Weather and Forecasting, 33, 671-691. https://doi.org/10.1175/WAF-D-17-0120.1 *
Nielsen, E.R., and R.S. Schumacher, 2018: Dynamical insights into extreme short-term precipitation associated with supercells and mesovortices. Journal of the Atmospheric Sciences, 75, 2983-3009. https://doi.org/10.1175/JAS-D-17-0385.1 *
* also attributable to 2015 VORTEX-SE grant
Project completed December 2018
updated 2019-07-16
Improved Understanding of Tornado Development and Risk using Models and Observations from VORTEX-SE 2017
D. Dawson, R. Tanamachi, M. Baldwin, D. Chavas (Purdue Univ.); S. Frasier (Univ. Massachusetts)
Outcomes:
- Extensive data sets collected during Spring 2017 VORTEX-SE observing campaign: U. Mass S-band profiling radar, Purdue x-band dual-pol, mobile disdrometers, mobile soundings.
- In progress at grant conclusion: “analyzed relationships between the spatial distributions of various statistical metrics of environmental parameters conducive to tornadoes and tornado activity across diurnal, seasonal, and interannual timescales. Results indicate significant departures in the southeast U.S. and provides a useful data-based foundation for broader climatological studies of severe weather, including under climate change.”
- “…directly quantified joint dependence of tornado activity on terrain variabililty and population density using Bayes Law in a Poisson regression framework and tested key sensitivities.”
Formal publications and reports (9 informal publications)
Hua, Z. and D.R. Chavas, 2019: The Empirical Dependence of Tornadogenesis on Elevation Roughness: Historical Record Analysis Using Bayes’s Law in Arkansas. J. Appl. Meteor. Climatol., 58, 401–411, https://doi.org/10.1175/JAMC-D-18-0224.1
Project completed December 2018
updated 2019-07-16
Improving Risk Communication and Reducing Vulnerabilities for Dynamic Tornado Threats in the Southeastern U.S.
J. Demuth (NCAR/MMM); K. Anderson (Univ. Colorado)
Outcomes:
- Study of January 2017 southern Georgia tornadoes based on Twitter
- Considerable research into how to best utilize Twitter to study these events
Formal publications and reports (None; 3 informal publications and presentations )
Project completed December 2018
updated 2019-07-16
Analysis and modeling of topographic influences on the atmospheric boundary layer: Potential impact on tornado evolution
K. Knupp, J. Mecikalski (Univ. Alabama Huntsville)
Outcomes:
- “An analysis of tornadogenesis patterns for the tornadoes that have impacted the [Southern Cumberland System] since October 2007 (the beginning of the NWS storm-based polygon warning program) reveals that a distinct concentration of tornadogenesis events has occurred along the northwestern edge of the Sand Mountain plateau.”
- “Important controls on boundary flows within the [Southern Cumberland System] include the terrain perpendicular wind component, static stability (Brunt-Vaisala frequency, N), and width/height of the terrain feature.”
- Significant changes in the low-level hodograph are apparent between lower terrain and higher terrain during one well-observed tornado event.
- “An ensemble of 16 WRF simulation runs was completed using different initial conditions from the GFS and NAM operational models, four different microphysics schemes (WRF single moment 6-class graupel, Thompson 2-moment graupel, Morrison 2-moment, and Milbrandt-Yau 2-moment), and two different planetary boundary layer schemes (YSU and MYJ).” Preliminary work suggests that none of the ensemble members are of high enough fidelity to use in further analyses of topographic influences.
Formal publications and reports (7 additional informal publications and presentations)
Lyza, A.W. and K.R. Knupp, 2018: A Background Investigation of Tornado Activity across the Southern Cumberland Plateau Terrain System of Northeastern Alabama. Mon. Wea. Rev., 146, 4261–4278, https://doi.org/10.1175/MWR-D-18-0300.1
Lyza, A. W., T. A. Murphy, B. T. Goudeau, P. T. Pangle, K. R. Knupp, and R. A. Wade, 2020: Observed near-storm environment variations across the southern Cumberland Plateau system in northeastern Alabama. Mon. Wea. Rev., 148(4): 1465–1482, https://doi.org/10.1175/MWR-D-19-0190.1
Project completed December 2018
updated 2019-07-16
Understanding the Variability of Southeastern Severe Storm Environments using Mobile Soundings during VORTEXSE
M. Brown (Mississippi State Univ.); R. Wade (Univ. Alabama Huntsville); T. Murphy (Univ. Louisiana Monroe)
Outcomes:
- Deployed and coordinated six mobile sounding units in the Spring 2017 field campaign of VORTEX-SE.
- Developed a wind smoothing algorithm for Windsond soundings.
- Examination of wind profiles across the edge of the Sand Mountain plateau show evidence of convergence and vertical vorticity near the edge, and enhanced hodographs on top of the plateau, in some severe storm environments.
Formal publications and reports (11 informal publications and presentations)
(Three manuscripts in progress or review)
Project in progress under no-cost extension (UAH and ULM) July 2019; project completed (MSU) December 2018.
updated 2019-07-17
Four-dimensional variability of Southeastern storm environments, with and without terrain
M. Parker (North Carolina State Univ.)
Outcomes:
- For High-Shear Low-CAPE environments, “…simulations reinforce the primary importance of large low-level shear and steep low-level lapse rates in these environments. The key to understanding this sensitivity appears to be the primary role played by both shear and stability in the production of intense low-level updrafts”
- “…simulations also strongly emphasize the role of vertical wind shear (and, especially, streamwise vorticity) in the lowest 500 m AGL in producing tornadic supercells.”
- “…simulations reveal structures within the low-level vorticity fields of a range of low-CAPE supercells that are similar to widely-studied higher-CAPE counterparts. However, it appears that the cold pool in the low-CAPE supercells are considerably weaker.” Also “…much of the baroclinity that is present in these storms is associated with hydrometeor loading, not thermal perturbations.”
- Simulations show that “…intense vortices in low-CAPE supercells are preceded by dramatic intensification of the updraft roughly 1 km above the ground…”. “…What is distinctive is that the vertical structures of the vortices are amazingly shallow.”
- “…proper representation of these weaker low-CAPE cold pools is extremely sensitive to the treatment of graupel vs. hail in the model’s microphysical parameterization.”
Formal publications and reports (4 additional informal publications and presentations)
Sherburn, K.D. and M.D. Parker, 2019: The Development of Severe Vortices within Simulated High-Shear, Low-CAPE Convection. Mon. Wea. Rev., 147, 2189–2216, https://doi.org/10.1175/MWR-D-18-0246.1 *
Coffer, B.E. and M.D. Parker, 2017: Simulated Supercells in Nontornadic and Tornadic VORTEX2 Environments. Mon. Wea. Rev., 145, 149–180, https://doi.org/10.1175/MWR-D-16-0226.1 **
Coffer, B.E. and M.D. Parker, 2018: Is There a “Tipping Point” between Simulated Nontornadic and Tornadic Supercells in VORTEX2 Environments?. Mon. Wea. Rev., 146, 2667–2693, https://doi.org/10.1175/MWR-D-18-0050.1 **
* also attributed to 2015 VORTEX-SE gran
** related to outcomes quoted above but not significantly funded via VORTEX-SE
Project completed December 2018
updated 2019-07-17
Convective mode and Tennessee tornadoes: Climatology, warning procedures, and false alarm rates
K. Ellis, L. Reyes Mason (Univ. Tennessee)
Outcomes:
- The three Tennessee-based CWAs experienced tornadoes from different convective mode types, but when outbreaks are removed the convective modes are no longer significantly different.
- Tornadic convective mode, season, and time of day were all strongly associated. Tornadic discrete supercells followed a traditional severe weather pattern of spring and daytime occurrences, and were associated with fewer false alarms. More QLCS tornadoes happened at night and during the winter.
- Cells in lines and clusters accounted for larger proportions of false alarms than tornadoes.
- Forecasters noted the challenge in detecting tornadoes in convective modes other than discrete supercells, including short-lived QLCS tornadoes and “messy” convection.
- Key forecaster concerns other than convective mode included storm speed, outbreaks, and lack of ground-truthing at night.
- Forecasters differed in their motivation to either warn on every tornado or avoid false alarms.
Formal publications and reports (one in review; 13 informal publications and presentations)
Project in progress under no-cost extension July 2019
updated 2019-08_25
VORTEX-SE: Core infrastructure enhancements, operations, and preliminary research activities supporting Spring 2017 field campaign events
K. Knupp (Univ. Alabama Huntsville)
Outcomes:
- “…continued analyses of profiler and radar data to document the variability in low-level clouds, thermodynamics, and wind (wind shear) for cold-season tornado events.”
- “…analysis of an unanticipated and isolated EF-2 tornado occurrence on 1 March 2016 near Birmingham, Alabama. The boundary layer environment of the tornado was very heterogeneous in space and unsteady in time, with what would typically be considered an excellent proximity sounding severely underestimating instability, and SPC mesoanalyses significantly underestimating wind shear.”
- Collected extensive data in northern AL on five events outside the VORTEX-SE formal 2017 formal field campaign, and ten events during the campaign.
Formal publications and reports (4 informal publications)
Coleman, T. A., A. W. Lyza, K. R. Knupp, K. Laws, and W. Wyatt, 2018: A significant tornado in a heterogeneous environment during VORTEX-SE. Electronic J. Severe Storms Meteor., 13 (2), 1–25. (download) *
* also attributed to 2015 VORTEX-SE grant above
Project completed June 2017
updated 2019-07-17
Multi-year WSR-88D radar climatology of tornadic storms in the SE United States
T. Smith, K. Ortega (NSSL)
Outcomes:
- Discovered major challenges in processing 88D for climatological work.
- Updated approach is underway and opportunities for collaborative research will commence ~late 2020.
Formal publications and reports: None.
Project in progress under no-cost extension July 2019
updated 2019-07-17
Real-Time Demonstration of a High-Resolution Rapid Refresh Ensemble During the VORTEX-SE Field Program
D. Dowell, C. Alexander, S. Benjamin (NOAA/ESRL)
Outcomes:
- 36-member HRRR-E realtime ensemble run on 34/37 days during the VORTEX-SE spring field campaign
- One novel aspect was sticknet assimilation
- Highlighted cases include 27 March 2017 (a relatively poor 12Z forecast of supercells improved greatly at 18Z); 5 April 2017 (high-impact event with major errors because of a glitch in water vapor assimilation); 22 April 2017 (northern AL supercells with good UH track forecasts, improving substantially during the morning); 30 April 2017 (well-forecast strongly-forced wavy QLCS)
Formal publications and reports
Grant Final Report is a comprehensive summary of this work.
Project completed June 2017
updated 2019-07-17
Application of machine-learning techniques to storm-scale ensemble forecasts
P. Skinner, C. Potvin, D. Wheatley, L. Wicker, K. Knopfmeier (NSSL and/or CIMMS)
Outcomes:
- Tentative: “Random forests can use environmental information to accurately classify NEWS-e mesocyclone objects as being likely to be matched to an observation or being particularly intense if provided with an appropriate training dataset.”
- Tentative: “In general, the size and intensity of mesocyclone objects are the best predictors of NEWS-e forecast skill in both the full and low CAPE datasets”
- Tentative: “For the low CAPE dataset, large storm-relative helicity is the best environmental predictor of a NEWS-e mesocyclone object being matched to an observed object.”
Formal publications and reports (2 additional informal publications and presentations)
Skinner, P.S., D.M. Wheatley, K.H. Knopfmeier, A.E. Reinhart, J.J. Choate, T.A. Jones, G.J. Creager, D.C. Dowell, C.R. Alexander, T.T. Ladwig, L.J. Wicker, P.L. Heinselman, P. Minnis, and R. Palikonda, 2018: Object-Based Verification of a Prototype Warn-on-Forecast System. Wea. Forecasting, 33, 1225–1250, https://doi.org/10.1175/WAF-D-18-0020.1 *
* also attributed to 2015 grant above
Project completed November 2017
updated 2019-07-17
Proposal to investigate the contribution of land surface and planetary boundary layer interactions to tornadogenesis in the Southeast US
T. Lee, M. Buban (Oak Ridge Universities); T. Meyers, B. Baker (NOAA/ARL/ATDD); D. Turner (NOAA/ESRL)
Outcomes:
- Lesson: “Limited predictability of mesoscale conditions made it difficult to determine IOPs several days in advance and complicated ideal deployment strategies several hours in advance.”
- Lesson: “The rapidly evolving mesoscale- to synoptic-scale environment made it difficult for teams from ATDD, as well as other groups, to position themselves ahead of storms…”
- Lesson: “Analyses of the rawinsonde observations underscored the importance of hourly rawinsonde launches, rather than launches at 2 or 3 hourly intervals.”
- Lesson: “The presence of low lifting condensation levels (LCLs), which were oftentimes <1000 m AGL throughout many of the IOPs in the 2016 and 2017 campaigns, prevented the computation of low level (i.e. 0-1 km) wind shear and helicity from the wind lidar LOS scans.”
Formal publications and reports (7 additional informal publications and presentations)
Dumas, E. J., T. R. Lee, M. Buban, and B. Baker, 2016: Small Unmanned Aircraft System (sUAS) measurements during the 2016 Verifications of the Origins of Rotation in Tornadoes Experiment Southeast (VORTEX-SE). NOAA Technical Memorandum OAR ARL-273. (non peer-reviewed)
Dumas, E. J., T. R. Lee, M. Buban, and B. Baker, 2017: Small Unmanned Aircraft System (sUAS) measurements during the 2017 Verifications of the Origins of Rotation in Tornadoes Experiment Southeast (VORTEX-SE). NOAA Technical Memorandum OAR ARL-274. (non peer-reviewed)
Project completed July 2017