NWS operational perspectives of the 21 June 2004 Amarillo hailstorm

A supercell thunderstorm battered the city of Amarillo on 21 June 2004, producing hail larger than softball size and eight tornadoes (total damage to Amarillo was over $300 million) during its several hour lifetime. The slow movement and close proximity of the storm to both the National Weather Service Forecast Office and the Amarillo WSR-88D afforded somewhat unusual warning opportunities, since the warning meteorologists were able to compare the radar display in near real-time to visual structure of the storm. The storm's proximity also facilitated an unusual ability to diagnose storm-scale processes from radar signatures that might otherwise have gone undetected on more distant storms owing to sampling elevation issues.

Of additional interest is the evolution of a second intense supercell that developed on the higher terrain of the western Texas Panhandle and moved southeast, again bearing down on Amarillo after dark. The second storm, generally overlooked by comparison, also produced a hook echo with a very strong mesocyclonic circulation that prompted several tornado warnings as it approached Amarillo, but had no documented tornadoes.

The synoptic and mesoscale environments that gave rise to the 21 June event will first be described briefly, and operations and warning decisions will then be examined from both radar and observational perspectives.