"Long-Track Microburst" Blasts Austin with 85 MPH Winds on May 28

On Wednesday, May 28, severe weather swept through parts of Austin as a supercell thunderstorm generated a "long-track microburst." 

This phenomenon resulted in damaging straight-line winds, leading to comprehensive assessments conducted by the National Weather Service (NWS) in Austin and San Antonio. 

The National Weather Service has unveiled a new map identifying the regions most severely affected by the recent intense wind event.

Harrison Tran, a meteorologist with the National Weather Service in Austin/San Antonio, reported that the most intense microburst winds, reaching speeds of up to 85 mph, significantly affected regions from Mopac to Austin-Bergstrom International Airport, including central, east, and southeast Austin. 

In a significant weather event, rear flank downdraft winds were recorded at speeds of up to 75 mph, impacting downtown Austin and areas to the southeast.

In a detailed explanation of the meteorological phenomenon, Tran highlighted that this specific microburst was triggered by substantial quantities of hail melting at elevated altitudes within the thunderstorm. The process led to a cooling of the surrounding air, which increased its density and caused it to descend rapidly to the ground. 

This phenomenon resulted in the formation of powerful straight-line winds reaching speeds of 85 miles per hour. In a simultaneous development, pressure patterns within the supercell drove calm mid-level winds downward, resulting in rear flank downdraft winds reaching speeds of 75 mph that impacted downtown.

A powerful supercell thunderstorm developed in the northern Hill Country, close to the San Saba and Lampasas county line, at approximately 4:30 p.m. on May 28. 

The National Weather Service's timeline indicates that the storm reached its maximum intensity at approximately 6:30 p.m. while passing through Austin, subsequently weakening as it advanced into Bastrop County later that evening.