3.1 An Analysis of the Record Breaking April 2016 San Antonio Hail Storm

Tuesday, 24 January 2017: 1:30 PM
Ballroom 6E (Washington State Convention Center )
Nicholas L. Hampshire, NOAA/NWS, New Braunfels, TX; and B. M. Fogarty
Manuscript (1.6 MB)

On April 12, 2016, a supercell thunderstorm developed west of Bexar County, Texas and intensified as it tracked east into the city of San Antonio. This supercell produced hail up 11.4 cm (4.5 in)  in diameter with a 5 km wide swath of 7+ cm  hail across the central portions of Bexar County. This storm broke the record as the costliest hailstorm in Texas with an estimated $1.4 billion in estimated insured losses. What was unique about the April 2016 storm was the apparent lack of strong instability that forecasters typically correlate with storms that produce giant hail.

This study will look into the specifics of the event and how the storm evolved through the evening hours. The thermodynamic environment, kinematic parameters, and other impactful fields will be analyzed to compare the findings with 53 other cases of hail storms which produced at least 10 cm hail stones between 2008 and 2016. Common radar signatures indicative of large hail and the presence of a mesocyclone will also be examined. These data will be used to discover any potential signals to help operational forecasters recognize the threat of highly destructive hail storms before and when the storms occur.  The study will also examine how the event was perceived by the public and possible best practices on forecasting and communication of the event.

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