Beta (2020)

A broad area of disturbed weather that had lingered over the western Gulf of Mexico finally organized into a tropical depression about 1200 UTC on 17 September 2020, roughly 305 nautical miles south‑southeast of Brownsville, Texas. The system became Tropical Storm Beta on 18 September and spent several days drifting slowly in the central and western Gulf. It briefly strengthened to a peak on 20 September, then weakened and re‑organized near the middle Texas coast before making landfall. Beta moved inland over Texas as a weakening system, became a depression later on 22 September, merged with a frontal system and became post‑tropical on 23 September, and dissipated over northeastern Alabama by early 25 September.

Beta made a single official landfall at Matagorda Bay, Texas, near 0245 UTC on 22 September. At landfall the cyclone had maximum sustained winds near 45 kt (about 50 mph) and a minimum sea‑level pressure around 997 mb. After landfall Beta weakened to a tropical depression later that day and then transitioned to an extratropical low as it merged with the frontal zone.

The maximum intensity observed for Beta was 55 kt (about 63 mph) at 1800 UTC on 20 September with a minimum central pressure of 993 mb. That peak was short‑lived and based on a blend of aircraft flight‑level winds, SFMR surface estimates, and Doppler radar indications; the storm did not reach hurricane strength.

Storm surge inundation of roughly 2–4 feet above ground level occurred along much of the Texas, Louisiana, and Mississippi coasts. The highest measured coastal water levels included 4.2 ft above MHHW at San Luis Pass (Galveston area) and up to 4.6 ft MHHW in the Manchester section of Houston (though that station had significant freshwater contribution from rainfall). In southeastern Louisiana, gauges recorded about 4.1–4.2 ft MHHW at Shell Beach and Delacroix (St. Bernard Parish). Rainfall was heaviest in southeastern Texas: Brookside Village in Harris County reported 15.77 inches, numerous nearby sites recorded 10–14 inches, and widespread totals of 3–7 inches occurred from the middle Texas coast into central Louisiana and west‑central Mississippi (with 10.05 in at Rosetta, MS and 9.60 in near Marion, LA).

Media reports indicate one direct death associated with Beta: a fisherman who disappeared into a swollen Brays Bayou near Houston and was later found drowned. Beta produced tropical‑storm‑force winds along portions of the middle and upper Texas coast, caused coastal flooding and minor wind damage, and its heavy rains produced moderate to major freshwater flooding in southern parts of the Houston metropolitan area, damaging at least 20–25 homes. The NOAA National Centers for Environmental Information estimated U.S. damage at about $225 million.

Noteworthy items: Beta’s development was slow and complex, which led to challenges in forecasting its genesis and some early overestimates of its peak intensity because nearby dry air limited strengthening. NHC track forecasts performed well overall at short to medium ranges once the storm consolidated, and observed storm surge and coastal water levels generally fell within the issued storm surge watches and warnings. There were no confirmed tornadoes tied to Beta.