Extreme Rainfall in Texas: Patterns and Predictability

Extreme rainfall, with storm total precipitation exceeding 500 mm, occurs several times per decade in Texas. According to a compositing analysis, the large-scale weather patterns associated with extreme rainfall events involve a northward deflection of the tropical trade winds into Texas, with deep southerly winds extending into the middle troposphere. One such event, the July 2002 South-Central Texas flood, is examined in detail. This particular event was associated with a stationary upper-level trough over central Texas and northern Mexico that established a steady influx of tropical moisture from the south. While the onset of the event was triggered by destabilization caused by an upper-level vortex moving over the northeast Mexican coast, a succession of upper-level processes allowed the event to become stationary over south-central Texas and produce heavy rain for several days. While the large-scale signatures of such extreme rain events evolve slowly, the many interacting processes at smaller scales make numerical forecasts highly sensitive to details of the simulations.

[1]  Jerome P. Charba,et al.  Comparative Verification of Recent Quantitative Precipitation Forecasts in the National Weather Service: A Simple Approach for Scoring Forecast Accuracy , 2003 .

[2]  J. Lafore,et al.  High-Resolution Non-Hydrostatic Simulations of Flash-Flood Episodes with Grid-Nesting and Ice-Phase Parameterization , 2000 .

[3]  D. Stensrud,et al.  Mesoscale Convective Systems in Weakly Forced Large-Scale Environments. Part II: Generation of a Mesoscale Initial Condition , 1994 .

[4]  J. Dudhia.  A Nonhydrostatic Version of the Penn State–NCAR Mesoscale Model: Validation Tests and Simulation of an Atlantic Cyclone and Cold Front , 1993 .

[5]  Yongkang Xue,et al.  The Impact of Land Surface Processes on Simulations of the U.S. Hydrological Cycle: A Case Study of the 1993 Flood Using the SSiB Land Surface Model in the NCEP Eta Regional Model , 2001 .

[6]  David R. Easterling,et al.  Long-Term Trends in Extreme Precipitation Events over the Conterminous United States and Canada , 1999 .

[7]  David G. Dritschel,et al.  The instability and breakdown of tall columnar vortices in a quasi-geostrophic fluid , 1996, Journal of Fluid Mechanics.

[8]  P. C. Patton,et al.  Geomorphic Response of Central Texas Stream Channels to Catastrophic Rainfall and Runoff , 1977 .

[9]  W. Asquith.  Depth-duration frequency of precipitation for Texas , 1998 .

[10]  J. Paegle,et al.  Diurnal Oscillations of Low-Level Jets, Vertical Motion, and Precipitation: A Model Case Study , 1993 .

[11]  C. Davis,et al.  Influence of Balanced Motions on Heavy Precipitation within a Long-Lived Convectively Generated Vortex , 2002 .

[12]  Howard B. Bluestein,et al.  Observations and theory of weather systems , 1993 .

[13]  Raymond M. Slade,et al.  Extreme precipitation depths for Texas, excluding the Trans-Pecos region , 1998 .

[14]  L. Bosart,et al.  A Case Study of Heavy Rainfall Associated with Weak Cyclogenesis in the Northwest Gulf of Mexico , 1992 .

[15]  D. Raymond,et al.  A Theory for Long-Lived Mesoscale Convective Systems , 1990 .

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

[17]  C. Doswell,et al.  Flash Flood Forecasting: An Ingredients-Based Methodology , 1996 .

[18]  E. Lorenz,et al.  The predictability of a flow which possesses many scales of motion , 1969 .

[19]  R. Rotunno,et al.  Effects of Moist Convection on Mesoscale Predictability , 2003 .

[20]  N. Seaman,et al.  A Comparison Study of Convective Parameterization Schemes in a Mesoscale Model , 1997 .

[21]  C. Chappell,et al.  Synoptic and Meso-α Scale Aspects of Flash Flood Events1 , 1979 .

[22]  Brian A. Colle,et al.  Multiseason Verification of the MM5. Part II: Evaluation of High-Resolution Precipitation Forecasts over the Northeastern United States , 2003 .

[23]  Thomas T. Warner,et al.  Nested-Model Simulation of Moist Convection: The Impact of Coarse-Grid Parameterized Convection on Fine-Grid Resolved Convection , 2000 .

[24]  William A. Gallus,et al.  Eta Simulations of Three Extreme Precipitation Events: Sensitivity to Resolution and Convective Parameterization , 1999 .

[25]  J. Kain,et al.  The role of the convective “trigger function” in numerical forecasts of mesoscale convective systems , 1992 .

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

[27]  William R. Cotton,et al.  Simulating convective events using a high‐resolution mesoscale model , 2000 .

[28]  Paul Roebber,et al.  The Sensitivity of Precipitation to Circulation Details. Part II: Mesoscale Modeling , 2002 .

[29]  Chris Snyder,et al.  Mesoscale Predictability of the “Surprise” Snowstorm of 24–25 January 2000 , 2002 .

[30]  C. Konrad.  The Most Extreme Precipitation Events over the Eastern United States from 1950 to 1996: Considerations of Scale , 2001 .

[31]  B. Hoskins,et al.  On the use and significance of isentropic potential vorticity maps , 2007 .

[32]  Charles A. Doswell,et al.  Comments on “An Operational Ingredients-Based Methodology for Forecasting Midlatitude Winter Season Precipitation” , 2002 .

[33]  Norman W. Junker,et al.  Evaluation of 33 Years of Quantitative Precipitation Forecasting at the NMC , 1995 .

[34]  J. Mailhot,et al.  Impact of horizontal resolution on the numerical simulation of a midlatitude squall line : Implicit versus explicit condensation , 2001 .

[35]  J. Smith,et al.  Catastrophic Rainfall and Flooding in Texas , 2000 .

[36]  William A. Gallus,et al.  Impact of Verification Grid-Box Size on Warm-Season QPF Skill Measures , 2002 .

[37]  Charles Cohen,et al.  A Comparison of Cumulus Parameterizations in Idealized Sea-Breeze Simulations , 2002 .

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

[39]  David G. Dritschel,et al.  The stability of a two-dimensional vorticity filament under uniform strain , 1991, Journal of Fluid Mechanics.