Rainfall Across the Rio Grande Valley/Deep South Texas ranchlands during the evening of May 9, 2014. |
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Squall Roars Across Ranchlands, Portions of Lower Valley May 9th Wind, Rain, and Lightning Alters Evening Plans for Many |
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Summary, in Brief Initial cells along the forming line produced wind gusts to near 70 mph in Laredo, along with notable damage. The continuation of strong winds produced pockets of damage in Jim Hogg, Zapata, and Starr County (below). 250 mb chart of streamlines (arrowed lines), isotachs (lines of equal wind), and observed wind and temperature, at around 7 PM May 9th. Note the small area of 100+ knot wind in south central Texas, with a pocket of less than 75 knot wind just north of the Rio Grande Valley. This difference was one factor in creating sufficient lift to help organize the line of strong to severe storms. |
Chart showing the height (in meters) of the 700 mb surface, observed winds and temperatures, and areas where moisture had "pooled" (Dew point temperature ≥-4°C), at around 7 PM May 9th. Note the area of >4°C dewpoint across Deep South Texas. This moisture, combined with cooler and somewhat drier air sliding over top of it, was sufficient to maintain the squall line as it approached and moved off the coast. Two clusters of developing storms, one edging south from the South Texas Brush Country and a second sliding east from the Rio Grande Plains, merged into a northeast–to–southwest oriented line at around 7 PM, extending from western Starr County through western Brooks County. The line would plow eastward (below left), with a number of individual stronger cells embedded within the line. As the line neared Hidalgo County, the strongest cells were found north of the Rio Grande Valley, including one with several quick forming and dissipating circulations (below right). At one point, most locations in Deep South Texas and the Rio Grande Valley were under a warning for the potential for 60 to 70 mph damaging winds, and a smaller area of ranches and farms from southeastern Jim Hogg through northwestern Willacy were under tornado warnings. The action continued to press southeast during the mid evening. After a slight weakening, the squall reintensified as it moved east of U.S. 77 from southern Kenedy to the Rio Grande. The strongest measured wind gusts occurred between 10 and 1130 PM in these areas, with many locations recording gusts over 50 mph. Accompanying the gusts were sheets of rain which dropped more than 2 inches in some locations, including Bayview/Cameron County Airport (2.07"), Armstrong (Southern Kenedy County, 2.65"), and Port Mansfield (2.94", along the coast on the Willacy/Kenedy County line). The storms knocked out power to some communities, including parts of South Padre Island, and caused significant disruption to evening flights in and out of Harlingen and Brownsville. A preliminary damage report follows. |
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000 NWUS54 KBRO 101453 LSRBRO PRELIMINARY LOCAL STORM REPORT...SUMMARY NATIONAL WEATHER SERVICE BROWNSVILLE TX 952 AM CDT SAT MAY 10 2014 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0635 PM TSTM WND DMG 1 N ZAPATA 26.91N 99.26W 05/09/2014 ZAPATA TX LAW ENFORCEMENT ROOF OF A BAKERY PARTIALLY REMOVED AND BLOWN ONTO HIGHWAY 83. 0701 PM TSTM WND DMG HEBBRONVILLE 27.32N 98.69W 05/09/2014 JIM HOGG TX EMERGENCY MNGR POWERLINES DOWN OVER THE ROADWAY IN HEBBRONVILLE. 0708 PM TSTM WND DMG SOUTH FORK ESTATES 27.27N 98.72W 05/09/2014 JIM HOGG TX LAW ENFORCEMENT WIND DAMAGE TO TRAILERS AND TREES IN THE SOUTH FORK ESTATES AT THE INTERSECTION OF FARM TO MARKET 3073 AND HIGHWAY 16. 0742 PM TSTM WND DMG 3 N RIO GRANDE CITY 26.42N 98.83W 05/09/2014 STARR TX PUBLIC MULTIPLE LARGE TREE LIMBS DOWN ON FM 735. 0759 PM TSTM WND DMG HEBBRONVILLE 27.32N 98.69W 05/09/2014 JIM HOGG TX LAW ENFORCEMENT SEVERAL POWER LINES DOWNED IN FALFURRIAS AND IN THE COUNTY ON HIGHWAY 223. TREES DOWN AT HIGHWAY 219 AND 206 0800 PM TSTM WND DMG MISSION 26.21N 98.32W 05/09/2014 HIDALGO TX PUBLIC LARGE LIMB OFF MESQUITE TREE...APPROXIMATELY 130 POUNDS. 0810 PM TSTM WND DMG EDINBURG 26.30N 98.16W 05/09/2014 HIDALGO TX FIRE DEPT/RESCUE SEVERAL POWER POLES DOWN AND POWER LINE TANGLED IN TREES THROUGHOUT THE CITY OF EDINBURG. 0826 PM TSTM WND DMG PALMVIEW 26.23N 98.37W 05/09/2014 HIDALGO TX LAW ENFORCEMENT SIGNS BLOWN DOWN ON THE EXPRESSWAY...HIGHWAY 83...INTERSTATE 2 IN PALMVIEW. 0834 PM TSTM WND DMG MISSION 26.21N 98.32W 05/09/2014 HIDALGO TX LAW ENFORCEMENT SEVERAL REPORTS OF TREES AND POWERLINES DOWNED IN MISSION AND SULLIVAN. 0859 PM TSTM WND DMG LYFORD 26.41N 97.79W 05/09/2014 WILLACY TX LAW ENFORCEMENT TREES DOWN IN LYFORD. SEMI TRUCK BLOWN OVER AT HIGHWAY 1015 AND 186. 0913 PM TSTM WND GST EDCOUCH 26.29N 97.96W 05/09/2014 E60 MPH HIDALGO TX TRAINED SPOTTER SPOTTER ESTIMATES 55 TO 60 MPH WINDS IN EDCOUCH. 1130 PM MARINE TSTM WIND 12 E SOUTH PADRE ISLAND 26.08N 96.99W 05/09/2014 M58 MPH GMZ150 TX COAST GUARD COAST GUARD RECEIVED A 50 KNOT WIND REPORT FROM A BOAT 12 MILES EAST OF SOUTH PADRE ISLAND JETTY. |
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0.5° reflectivity loop from 724 PM to 829 PM CDT across Deep South Texas and the Rio Grande Valley. Note the stronger cells across the ranchlands from Jim Hogg through northwest Willacy County. |
0.5° velocity loop from 724 PM to 829 PM, focused along the Deep South Texas ranchlands. Note the pockets where rotation appears (light green/blue against red) and the general "surge" of inbound (green and blue) winds racing toward the Lower RGV. |
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0.5° velocity loop from 946 and 1049 PM, focused along the Lower Texas coast, mainly east of Highway 77. Note the broad area of bright green and light blue, indicating radar estimated 45 to 60 mph winds - and the duration of such winds. Surface observations in the area recorded 45 to 55 mph wind gusts for up to an hour. |