Evaluation of WRF Forecasts of Tornadic and Nontornadic Outbreaks when Initialized with Synoptic-Scale Input

Uncertainty exists concerning the links between synoptic-scale processes and tornado outbreaks. With continuously improving computer technology, a large number of high-resolution model simulations can be conducted to study these outbreaks to the storm scale, to determine the degree to which synoptic-scale processes appear to influence the occurrence of tornado outbreaks, and to determine how far in advance these processes are important. To this end, 50 tornado outbreak simulations are compared with 50 primarily nontornadic outbreak simulations initialized with synoptic-scale input using the Weather Research and Forecasting (WRF) mesoscale model to determine if the model is able to distinguish the outbreak type 1, 2, and 3 days in advance of the event. The model simulations cannot resolve tornadoes explicitly; thus, the use of meteorological covariates (in the form of numerous severe-weather parameters) is necessary to determine whether or not the model is predicting a tornado outbreak. Results indicate that, using the covariates, the WRF model can discriminate outbreak type consistently at least up to 3 days in advance. The severe-weather parameters that are most helpful in discriminating between outbreak types include low-level and deep-layer shear variables and the lifting condensation level. An analysis of the spatial structures and temporal evolution, as well as the magnitudes, of the severe-weather parameters is critical to diagnose the outbreak type correctly. Thermodynamic instability parameters are not helpful in distinguishing the outbreak type, primarily because of a strong seasonal dependence and convective modification in the simulations.

[1]  R. C. Miller,et al.  A Basis for Forecasting Peak Wind Gusts in Non-Frontal Thunderstorms , 1954 .

[2]  D. Stensrud,et al.  Interpreting the Climatology of Derechos , 2004 .

[3]  D. Stensrud,et al.  Mesoscale Convective Systems in Weakly Forced Large-Scale Environments. Part III: Numerical Simulations and Implications for Operational Forecasting , 1994 .

[4]  R. Beebe.  TORNADO COMPOSITE CHARTS , 1956 .

[5]  G. Grell,et al.  A generalized approach to parameterizing convection combining ensemble and data assimilation techniques , 2002 .

[6]  L. L. Means,et al.  A Synoptic Study on the Formation of Squall Lines in the North Central United States , 1955 .

[7]  J. Fritsch,et al.  Bow Echo Sensitivity to Ambient Moisture and Cold Pool Strength , 2006 .

[8]  J. Molinari,et al.  Parameterization of Convective Precipitation in Mesoscale Numerical Models: A Critical Review , 1992 .

[9]  D. Stauffer,et al.  On Improving 4-km Mesoscale Model Simulations , 2006 .

[10]  A. Blackadar.  Boundary Layer Wind Maxima and Their Significance for the Growth of Nocturnal Inversions , 1957 .

[11]  Harold E. Brooks,et al.  16.3 BASELINE CLIMATOLOGY OF SOUNDING DERIVED PARAMETERS ASSOCIATED WITH DEEP, MOIST CONVECTION , 2002 .

[12]  J. G. Galway,et al.  Some Climatological Aspects of Tornado Outbreaks , 1977 .

[13]  Harold E. Brooks,et al.  The spatial distribution of severe thunderstorm and tornado environments from global reanalysis data , 2003 .

[14]  Richard L. Thompson,et al.  An Overview of Environmental Conditions and Forecast Implications of the 3 May 1999 Tornado Outbreak , 2000 .

[15]  Michael E. Baldwin,et al.  Properties of the Convection Scheme in NCEP's Eta Model that Affect Forecast Sounding Interpretation , 2002 .

[16]  Brynn W. Kerr,et al.  Storm-Relative Winds and Helicity in the Tornadic Thunderstorm Environment , 1996 .

[17]  Harold E. Brooks,et al.  Discriminating between Tornadic and Nontornadic Thunderstorms Using Mesoscale Model Output , 1997 .

[18]  I. Orlanski.  A rational subdivision of scales for atmospheric processes , 1975 .

[19]  J. G. Galway.  Relationship of Tornado Deaths to Severe Weather Watch Areas , 1975 .

[20]  Avid,et al.  A Five-Year Climatology of Elevated Severe Convective Storms in the United States East of the Rocky Mountains , 2022 .

[21]  Harold E. Brooks,et al.  Comparison between Observed Convective Cloud-Base Heights and Lifting Condensation Level for Two Different Lifted Parcels , 2002 .

[22]  Kelvin K. Droegemeier,et al.  The Influence of Helicity on Numerically Simulated Convective Storms , 1993 .

[23]  H. D. Orville,et al.  Bulk Parameterization of the Snow Field in a Cloud Model , 1983 .

[24]  Boris Katz,et al.  Recent Changes Implemented into the Global Forecast System at NMC , 1991 .

[25]  Richard L. Thompson,et al.  A Simple and Flexible Method for Ranking Severe Weather Events , 2006 .

[26]  Jordan G. Powers,et al.  A Description of the Advanced Research WRF Version 2 , 2005 .

[27]  Masao Kanamitsu,et al.  Description of the NMC Global Data Assimilation and Forecast System , 1989 .

[28]  Thomas P. Grazulis.  Significant tornadoes, 1680-1991 , 1993 .

[29]  Charles A. Doswell,et al.  Proximity sounding analysis for derechos and supercells: an assessment of similarities and differences , 2003 .

[30]  Complex quality control of rawinsonde heights and temperatures (CQCHT) at the National Meteorological Center , 1992 .

[31]  J. Dudhia.  Numerical Study of Convection Observed during the Winter Monsoon Experiment Using a Mesoscale Two-Dimensional Model , 1989 .

[32]  Robert C Miller,et al.  Notes on Analysis and Severe-Storm Forecasting Procedures of the Air Force Global Weather Central , 1972 .

[33]  T. Glickman,et al.  Glossary of Meteorology , 2000 .

[34]  Charles A. Doswell,et al.  Shear Parameter Thresholds for Forecasting Tornadic Thunderstorms in Northern and Central California , 2003 .

[35]  R. C. Miller,et al.  A Mean Sounding Representative of the Tornadic Airmass Environment , 1952 .

[36]  Alan R. Moller,et al.  Severe Local Storms Forecasting , 2001 .

[37]  Matthew J. Bunkers.  Vertical Wind Shear Associated with Left-Moving Supercells , 2002 .

[38]  Stephen J. Lord,et al.  The New Global Operational Analysis System at the National Meteorological Center , 1991 .

[39]  Richard L. Thompson,et al.  Close Proximity Soundings within Supercell Environments Obtained from the Rapid Update Cycle , 2003 .

[40]  Frank P. Colby,et al.  Convective Inhibition as a Predictor of Convection during AVE-SESAME II , 1984 .

[41]  R. Reynolds,et al.  The NCEP/NCAR 40-Year Reanalysis Project , 1996, Renewable Energy.

[42]  H. Pan,et al.  Nonlocal Boundary Layer Vertical Diffusion in a Medium-Range Forecast Model , 1996 .

[43]  Song-You Hong,et al.  Implementation of Prognostic Cloud Scheme for a Regional Spectral Model , 1998 .

[44]  J. Holton.  An introduction to dynamic meteorology , 2004 .

[45]  Charles A. Doswell,et al.  The Tornado : its structure, dynamics, prediction, and hazards , 1993 .

[46]  Robert A. Maddox,et al.  An Evaluation of Tornado Proximity Wind and Stability Data , 1976 .

[47]  D. Stensrud.  Importance of Low-Level Jets to Climate: A Review. , 1996 .

[48]  Charles A. Doswell,et al.  On the Use of Mesoscale and Cloud-Scale Models in Operational Forecasting , 1992 .

[49]  Doswell,et al.  Historical overview of severe convective storms research , 2007 .

[50]  Charles A. Doswell,et al.  Small Sample Size and Data Quality Issues Illustrated Using Tornado Occurrence Data , 2007 .

[51]  Arun Kumar,et al.  A Multiseason Climate Forecast System at the National Meteorological Center. , 1994 .

[52]  J. Nielsen‐Gammon,et al.  Low-Level Jet Development during a Numerically Simulated Return Flow Event , 1998 .

[53]  Steven E. Koch,et al.  The Impact of Different WRF Model Physical Parameterizations and Their Interactions on Warm Season MCS Rainfall , 2005 .

[54]  Joseph T. Schaefer,et al.  Severe Thunderstorm Forecasting: A Historical Perspective , 1986 .

[55]  Charles A. Doswell,et al.  Climatological Estimates of Daily Local Nontornadic Severe Thunderstorm Probability for the United States , 2005 .

[56]  E. Mlawer,et al.  Radiative transfer for inhomogeneous atmospheres: RRTM, a validated correlated-k model for the longwave , 1997 .

[57]  Louis J. Wicker,et al.  Time-Splitting Methods for Elastic Models Using Forward Time Schemes , 2002 .

[58]  Charles A. Doswell,et al.  The Role of Midtropospheric Winds in the Evolution and Maintenance of Low-Level Mesocyclones , 1994 .

[59]  William G. Collins,et al.  Comprehensive Hydrostatic Quality Control at the National Meteorological Center , 1990 .

[60]  R. Johns.  A Synoptic Climatology of Northwest-Flow Severe Weather Outbreaks. Part II: Meteorological Parameters and Synoptic Patterns , 1984 .

[61]  John Derber,et al.  The National Meteorological Center's spectral-statistical interpolation analysis system , 1992 .

[62]  Thomas M. Smith,et al.  Improved Global Sea Surface Temperature Analyses Using Optimum Interpolation , 1994 .

[63]  E. Rasmussen,et al.  A Baseline Climatology of Sounding-Derived Supercell and Tornado Forecast Parameters , 1998 .

[64]  L. Bosart,et al.  Extratropical Synoptic-Scale Processes and Severe Convection , 2001 .

[65]  Charles A. Doswell,et al.  On the Environments of Tornadic and Nontornadic Mesocyclones , 1994 .