Meteorological cause and characteristics of widespread heavy precipitation in the Texas Gulf watershed 2003–2018

Abstract

AbstractRecent pluvial years, extreme precipitation, and highly variable precipitation in the Southern Plains have produced substantial socioeconomic damage. While numerous studies examine the characteristics of heavy precipitation, explicit identification of meteorological ‘cause’ (e.g., thunderstorms, extratropical cyclones, weather fronts, etc.) is often excluded from climatological analyses. This work examines the meteorological cause and associated characteristics of widespread heavy precipitation (WHP) in the Texas‐Gulf watershed, using 16 years of weather observations and Stage IV multi‐sensor precipitation. WHP days are those with heavy rain (24‐hr accumulation at or above 95th percentile) that have spatial coverage and/or basin‐wide accumulations ≥90th percentile. Using expert assessment, WHP days and events (the latter as the total duration of distinct weather system in the watershed) are categorized into meteorological causes. WHP days possess longer durations and higher rain rates, and are important contributors to annual accumulation. Disaggregation of WHP days/events by cause reveals notable seasonal and interannual variability, with a tendency for frontal systems to dominate annually. Recent pluvial years have featured increased duration of frontal systems, while dry years showed a dearth of extratropical cyclones and summer mesoscale convection. While duration is statistically distinct between different cause categories for certain seasons and causes, rain‐rates generally were generally not found to depend on the event type. WHP events were accompanied by numerous meteorological and surface hazards, most notably severe thunderstorms during spring and summer, while the proportional contribution of flood hazard reports peaked during the fall. Ultimately, the climatological information extracted from this work may benefit researchers, planners, and water‐resource professionals dealing with precipitation extremes in the region.