Loop of 0.5° base velocity images between 447 and 529 PM CDT May 8th, across northern Hidalgo County along and near Highway 281. Radar estimated winds just below 70 mph at 5500 feet above the ground (pink color surrounded by bright green) crossed the highway at approximately 511 PM and produced damage. |
Loop of 0.5° base reflectivity images between 447 and 529 PM CDT May 8th, across northern Hidalgo County along and near Highway 281. The core of the highest reflectivity, at least 78 dbZ, was well above the freezing level and corresponded to blinding rain mixed with hail. |
Overview
The leading edge of a slow moving upper level disturbance across the southwest U.S. induced thunderstorms across the Sierra Madre Oriental during the early morning hours of May 8th. These storms moved into the Rio Grande Plains toward noon, then linked up with additional lift from an approaching wind shift line drifting south from the South Texas Plains. Feeding on a very unstable atmosphere (cold and dry air well above the earth’s surface), initial storms would slam Zapata County during lunchtime with damaging wind, large hail, flooding rain, and frequent lightning (see photos below). As the afternoon progressed, increasing contrast between cooler air across the South Texas Plains (60s and 70s) with the last of the early May heat in the Rio Grande Valley (90s) set the stage for additional storms with damaging winds and flooding rain in Zapata, and culminated with a "monster" supercell thunderstorm which cruised from southwest Brooks County through Raymondville before weakening.
Huge Storm Avoids McAllen/Pharr/Edinburg...This Time
Similar to events on March 29th and April 20th, one impressive supercell storm dominated the conversation (above). Fortunately for the populated middle Valley, where more than 700,000 persons are at risk, this cell slid through northern Hidalgo County north of the SR 186 and U.S. 281 interchange, and accelerated through the Lower Rio Grande Valley National Wildlife Refuge northeast of Linn and San Manuel before reaching Raymondville (Willacy County). The cell quickly weakened by the end of dinner hour (6 to 7 PM). In Raymondville, 50 to 60 mph winds may have contributed to a fallen power line – a line which fed 2,000 residents with electricity. Across the Highway 281 corridor, 6 miles north of Linn, the few residents and some drivers were not so fortunate. A list of impacts is summarized as follows as the macroburst peaked in intensity around 510 PM CDT:
- 102 mph instantaneous wind gust at a temporary 10 meter wind platform; 50 mph sustained winds for 35 minutes
- One injury to a truck driver who’s trailer turned over on the side of U.S. 281. The driver had pulled onto the improved shoulder due to blinding rain and pelting hail. Soon after, the downburst moved the trailer onto the dirt shoulder, and then turned it over. The trailer was carrying 5 tons of cargo (vacuum cleaners) and at least 200 gallons of diesel, which had to be removed from the scene.
- The precinct Constable, who lives on a ranch about a mile southwest of the truck incident, reported numerous asphalt shingles pulled from the northwest facing roof, and one window blown out.
- Numerous mesquite trees were snapped or had large healthy limbs broken; healthy ebony and oak trees were also damaged on the ranch.
- Heavy cable was torn out of a telephone tower at an estimated height of 200 feet above the ground. The tower was 0.2 miles southeast of the ranch house.
- Gages across the ranch measured 4 to 4.5 inches of rainfall, with high standing water on unpaved roads and in some of the fields
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Some photos will be posted here, or to our Facebook Page, from the damage. A news archive of the event can be found here. A preliminary report follows.
PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
855 PM CDT TUE MAY 08 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1211 PM HEAVY RAIN SAN YGNACIO 27.03N 99.45W
05/08/2012 E1.00 INCH ZAPATA TX TRAINED SPOTTER
1235 PM TSTM WND GST ZAPATA 26.89N 99.26W
05/08/2012 M62.00 MPH ZAPATA TX AWOS
1238 PM TSTM WND DMG 15 NW ZAPATA 27.05N 99.43W
05/08/2012 ZAPATA TX EMERGENCY MNGR
THREE TO FOUR HOMES WITH ROOF DAMAGE IN SAN YGNACIO AS
WELL AS ONE MOBILE HOME DESTROYED.
0103 PM TSTM WND DMG ZAPATA 26.89N 99.26W
05/08/2012 ZAPATA TX PUBLIC
SEVERAL TREES DOWN AROUND 4 INCHES IN DIAMETER AT 4TH AND
FLORES STREETS IN ZAPATA.
0323 PM HAIL ZAPATA 26.89N 99.26W
05/08/2012 E1.00 INCH ZAPATA TX PUBLIC
QUARTER SIZE HAIL REPORTED AT LINCOLN AND 5TH STREET.
0326 PM TSTM WND GST ZAPATA 26.89N 99.26W
05/08/2012 E60.00 MPH ZAPATA TX PUBLIC
WIND GUSTS ESTIMATED 60 TO 65 MPH AT LINCOLN AND 5TH
STREET.
0335 PM HEAVY RAIN ZAPATA 26.89N 99.26W
05/08/2012 U0.00 INCH ZAPATA TX LAW ENFORCEMENT
STREET FLOODING WITH BRIEFLY UP TO 3 FEET OF MOVING WATER
NEAR INTERSECTION OF IRENE AND US 83.
0515 PM FUNNEL CLOUD ELSA 26.30N 97.99W
05/08/2012 HIDALGO TX PUBLIC
FUNNEL CLOUD REPORTED ON HWY 107 NEAR ELSA AT CORNER OF
CURVE AND DOOLITTLE.
0542 PM MARINE TSTM WIND 18 N PORT MANSFIELD 26.80N 97.47W
05/08/2012 M40.00 MPH GMZ135 TX BUOY
TCOON PLATFORM RINCON DEL SAN JOSE REPORTED WIND GUST OF
35 KNOTS OR 40 MPH.
0605 PM TSTM WND GST RAYMONDVILLE 26.48N 97.78W
05/08/2012 E60.00 MPH WILLACY TX EMERGENCY MNGR
WILLACY COUNTY EMERGENCY MANAGER REPORTS 50 TO 60 MPH
WINDS OCCURRED IN RAYMONDVILLE.
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