National Weather Service United States Department of Commerce


By Mike Johnson, Mike Buchanan, and John Metz



General Weather Summary

The atmosphere was quite unstable over the weekend with very little capping inversion in place. Precipitable water had increased to around 1.7 inches by Sunday morning (the 29th), providing ample fuel for convective development. Maximum temperatures during the afternoon hours ranged from near 90 degrees along the coast to the lower 100s along the Rio Grande with dewpoints in the low to mid 70s. The upper-level pattern consisted of a strong shortwave trough moving across northern Mexico with several weaker vorticity maxima embedded in the flow. There was also a 250 millibar jet streak approaching from the southwest with south Texas located somewhat favorably in the left exit region. Low-level wind shear was sufficient to develop and sustain supercells with south-southeast winds around 10 mph at the surface veering to the southwest at 30 mph at 850 millibars. Temperatures aloft were not extraordinarily cold with 500 millibar temperatures generally ranging from -10 to -12 Celsius and the wet-bulb zero heights were generally running around 13 thousand feet.


Severe Weather Event and Impacts

At 21Z, SPC analysis plots showed MUCAPE values of around 5000 J/kg over the southern coastal bend. It was in this area where the first cells developed. An isolated shower over southwestern Nueces County quickly morphed into an HP supercell that moved to the right of the mean wind and produced very heavy rainfall and hail to the size of quarters over southern Nueces and northern Kleberg counties. As the sea-breeze propagated to the west of the storms, the low-level wind backed more to the southeast, increasing the low-level wind shear even further. More storms began to develop to the north and west of the initial development as the main upper-level support began to affect the area and the sea-breeze moved farther inland. These storms quickly became severe and remained more scattered in nature for the next several hours, producing hail to the size of golf balls and very heavy rainfall in excess of 4 inches.

Later in the evening, several cells over the Rio Grande Plains merged together to form a quasi- linear convective system which began to bow out as it approached the city of Alice. The rear-inflow jet was translated to the surface and winds of 64 mph were recorded at the Alice ASOS and wind damage was reported across the city. This line continue to move to the east and continued to produce wind damage from Odem, to Robstown, to Kingsville before finally affecting Corpus Christi and moving into the Gulf of Mexico.




Upper Air Data