Flash flooding in the Hill Country of Texas
1-minute Mesoscale Domain Sector GOES-18 (GOES-West) Infrared Window images (above) included plots of Flood Watch/Warning/Advisory polygons (Flash Flood Warnings appeared as red polygons, while Flash Flood Emergencies appeared as bold red polygons) across the Hill Country of Texas on 16 July 2026. After the previous few days of heavy rainfall — which produced amounts in excess of 25-28 inches in Kerr County and Uvalde County — the high rainfall rates of these latest thunderstorms caused considerable flash flooding (with at least 2 fatalities being reported). Note: a GOES-18 Mesoscale Sector was positioned over Texas at that time, since GOES-19 was still in “safehold” mode after experiencing an anomaly on the previous day.
A less-cluttered view of 1-minute GOES-18 Infrared Window images (below) made it easier to see the pulses of cold overshooting tops, and the 1-hour precipitation amounts that occasionally exceeded 1-2 inches at a couple of METAR sites. GOES-18 Rainfall Rate derived product values were as high as 1.31 inches per hour just north of Uvalde at 0804 UTC (the Uvalde METAR site had just received 1.20 inches of rainfall during the previous hour).
The coldest GOES-18 cloud-top infrared brightness temperature associated with the convection was -77.83 C; according to a plot of rawinsonde data from Del Rio, Texas (below) this temperature was not far below the Most Unstable (MU) air parcel’s Maximum Parcel Level (MPL), which represented a significant overshoot of its Equilibrium Level (EL).
1-minute GOES-18 Infrared Window images with plots of 1-minute GLM Flash Points (below) revealed considerable lightning activity with these thunderstorms that produced heavy rainfall.