The Mayfest High-Precipitation Supercell of 5 May 1995 - A Case Study


E. Brian Curran, Alan R. Moller, Edward J. Calianese and Michael P. Foster
NOAA/NWSFO Fort Worth, Texas

On 5 May 1995, the costliest severe thunderstorm event in United States history occurred when a severe high precipitation supercell and squall line struck the Dallas/Fort Worth Metro-plex. The supercell produced large hail, some the size of softballs and driven by winds in excess of 35 m·s-1, across a large swath of Tarrant county. Over one hundred people were injured when the storm struck an outdoor festival just south of downtown Fort Worth. The squall line merged with the supercell between Dallas and Fort Worth, then slowed considerably over western Dallas county. The resulting extreme rainfall rates over an urbanized area led to record-breaking flash flooding. This severe weather and flash flood event killed 20 people and injured hundreds, with nearly two billion dollars in property loss reported.
Using multiple data sets, we explore the meteorological conditions leading to this event. In addition, we examine and discuss the radar characteristics and evolution of both the supercell and the supercell/squall line merger. Lastly, we present rain gauge data and address the use of these data in realtime warning operations.