A deep upper level disturbance moved from Canada south into the Rockies, linked up with the persistent subtropical jet farther south to generate widespread dangerous thunderstorms across Texas. Storms initiated just before sunset east of the Sierra Madre, and produced some action across the Upper Valley and ranchlands.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS BRO wrote it up.
A deep upper level disturbance moved from Canada south into the Rockies, linked up with the persistent subtropical jet farther south to generate widespread dangerous thunderstorms across Texas. Storms initiated just before sunset east of the Sierra Madre, and produced some action across the Upper Valley and ranchlands. Quarter size hail and 40 to 45 mph winds were observed in Zapata.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Brownsville, TX wrote its last area forecast discussion before the first event at Apr 18, 5:33 PM CST, 2 hours 49 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BROWNSVILLE TX 633 PM CDT SAT APR 18 2015 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...A FEW SHOWERS HAVE ATTEMPTED TO GET GOING OVER THE COASTAL COUNTIES OF DEEP SOUTH TEXAS...HOWEVER THEY HAVE LARGELY FIZZLED OUT DUE TO A MORE STABLE ATMOSPHERE AIDED BY THE FRIDAY EVENING/NIGHT CONVECTION. CURRENT SATELLITE IMAGERY DOESN/T SHOW ANY CONVECTION IN THE VICINITY OF THE AERODROMES AND THIS HAS BEEN REMOVED FROM THE PREVIOUS TAFS. SURFACE WINDS WILL LIKELY REMAIN TOO STRONG OVERNIGHT TO ALLOW FOR SIGNIFICANT FORMATION OF FOG...BUT A TEMPO HAS BEEN INCLUDED FOR LIGHT FOG DEVELOPMENT FOR NEAR SUNRISE SUNDAY MORNING. PREVIOUSLY-LOWER CEILINGS HAVE BEEN BEEN DUMPED IN FAVOR OF THE MID AND HIGH LEVEL CLOUDINESS STREAMING OVERHEAD OUT OF NEIGHBORING MEXICO. OVERALL...VFR SHOULD BE THE RULE THROUGH THE NEXT 24 HOURS. && .PREV DISCUSSION... /ISSUED 255 PM CDT SAT APR 18 2015/ SHORT TERM.../NOW THROUGH SUNDAY NIGHT/...A LOW PRESSURE SYSTEM CENTERED OVER EASTERN COLORADO IS MAINTAINING A BROAD AREA OF DIFFLUENT FLOW ALOFT OVER SOUTH CENTRAL TEXAS. ALSO ...A VERY ACTIVE SUB TROPICAL JET WITH SHORTWAVES WITHIN THE FLOW IS MOVING ACROSS SOUTH TX UNDERNEATH THIS LOW. THIS WILL CONTINUE TO PRODUCE NUMEROUS SHOWERS AND THUNDERSTORMS ALONG THE LOWER TEXAS GULF WATERS NORTHEAST INTO THE NORTHWEST GULF COAST. THERE IS AN AREA OF CONVECTION DEVELOPING ALONG A STATIONARY FRONT WHICH IS INTERACTING WITH PLENTY OF DEEP LAYER MOISTURE AND INSTABILITY POOLED ALONG IT. NEAR THE SURFACE DEW POINTS RANGE FROM 70 TO 75 DEGREES AND PRECIPITABLE WATER VALUES IN THE LAST KBRO 12Z SOUNDING SHOWS 1.96 INCHES AND THE LATEST RAP MODEL RUN SHOWS PWATS OF 1.5 TO 1.9 INCHES ESPECIALLY FROM HIDALGO COUNTY NORTHEAST AND EAST TOWARDS THE COAST. IN ADDITION...THE A SLIGHT BREAK IN THE CLOUDS IS ALLOWING FOR TEMPS TO WARM UP FOR THE NEXT FEW HOURS RESULTING IN INCREASE INSTABILITY ACROSS THE AREA. THIS WILL RESULT IN A CONTINUATION OF THE CONVECTION IN THE LATE AFTERNOON THROUGH THE OVERNIGHT HOURS THROUGH MIDNIGHT. THE CONVECTION WILL ALSO BE ENHANCE ALONG THE SIERRA MADRE AND MOVE NORTHEAST WHICH WILL MAKE ITS WAY INTO STARR AND HIDALGO COUNTY LATE EVENING INTO THE OVERNIGHT. THE MAIN THREAT WITH THESE STORMS WILL BE VERY HEAVY DOWNPOURS PRODUCING FLOODING...STRONG DAMAGING WINDS...HAIL AND FREQUENT CG LIGHTNING. INTO SUNDAY THE UPPER LEVEL JET WILL MAKE ITS WAY INTO SOUTH TEXAS PROVIDING SUPPORT FOR SOME CONVECTION TO DEVELOP SUNDAY AFTERNOON. EXPECT THE BEST POTENTIAL TO REMAIN ALONG THE COAST DUE TO THE INSTABILITY IN THE AREA. EXPECT A FEW OF THE STORMS TO BECOME SEVERE. THE CLOSED LOW BECOMES AN OPEN WAVE AS IT MOVES NORTHEAST INTO THE GREAT LAKES SUNDAY NIGHT PUSHING A COLD FRONT BEHIND IT ALONG THE CENTRAL PLAINS. THE CONVECTION WILL BE ENHANCE EVEN MORE OVERNIGHT SUNDAY ASSOCIATED TO THE BOUNDARY AS THE FRONT APPROACHES THE AREA. THE FRONT WILL ARRIVED BY THE END OF THE SHORT TERM OVER THE NORTHERN RANCHLANDS EARLY MONDAY MORNING. LONG TERM.../MONDAY THROUGH SATURDAY/...THE CLOSED LOW THAT HAS BEEN PLAUGING THE REGION WITH INTERMITTENT THUNDERSTORMS FOR THE LAST SEVERAL DAYS OPENS UP AND MERGES WITH A SHARP SHORTWAVE TROUGH UPPER TROUGH MOVING OUT OF CANADA. THE RESULT WILL BE A LARGE SCALE UPPER TROUGH DEVELOPING MONDAY INTO TUESDAY FROM THE NORTHERN PLAINS TO THE MIDWEST EXTENDING SOUTH INTO THE GULF SOUTH. THIS SENDS A COLD FRONT THROUGH SOUTH TEXAS SUNDAY NIGHT MOVING OFFSHORE THE LOWER TEXAS COAST AS EARLY AS SUNRISE MONDAY. MODELS ARE IN GOOD AGREEMENT AND REMAIN VERY CONSISTENT WITH THE EVOLUTION OF THE UPPER LEVEL AND SURFACE FEATURES. MODERATE TO HIGH CONFIDENCE IN THE FORECAST THROUGH TUESDAY MAINTAINS A LOWERING OF TEMPERATURES AND HIGHER CHANCES OF RAINFALL. THE COOLING OF THE LOWER ATMOSPHERE, LOWER LAPSE RATES, WEAKENING INSTABILITY WILL LIMIT THE THUNDERSTORM INTENSITY AND SEVERE WEATHER PROBABILITIES GO WAY LOW. GFS MODEL SOUNDING CONTINUE TO INDICATE THE BEST CHANCE OF THUNDER MONDAY MORNING AS THE FRONTAL BOUNDARY PASSES THROUGH BUT AS THE COOLER SURFACE AIR SETTLES IN THE INSTABILITY QUICKLY WEAKENS. ANY THUNDERSTORMS THAT LINGER INTO THE MONDAY AFTERNOON AND EVENING WILL BE ELEVATED. AS WE MOVE INTO TUESDAY AND THE REST OF THE WEEK THE FRONT INITIALLY REMAINS STATIONARY NEAR OR JUST SOUTH OF THE REGION KEEPING A MOIST EASTERLY FLOW AND POSSIBLY THE HIGHEST CHANCE OF RAIN. BOTH GFS AND ECMWF INDICATE ON AVERAGE THAT TUESDAY WILL HAVE THE BEST COVERAGE OF RAIN. THIS WILL ALSO KEEP TEMPERATURES BELOW NORMAL. AFTER TUESDAY FORECAST TRENDS DOWNWARD ON THE RAIN AND UP WITH THE TEMPERATURES. THE FRONT EVENTUALLY DISSIPATES OR MOVES BACK NORTH AS SHORTWAVE RIDGING BUILDS OVER WESTERN TEXAS WITH THE NEXT UPPER TROUGH APPROACHING THE PACIFIC COAST. GFS AND ECMWF DO LITTLE WITH THIS TROUGH AND IT LOOKS MUCH WEAKER THEN THE LAST FEW TROUGHS. SOME PERTURBATIONS DO ADVANCE THROUGH THE TROUGH AND RIDE ALONG STOUT SOUTHWESTERLY UPPER JET AND MAY SPARK SOME AFTERNOON CONVECTION OVER THE SIERRA MADRE AND THEN DRIFT INTO OUR CWA EACH AFTERNOON AND EVENING. THIS WILL BE INDICATED BY LOW GRADE POPS EACH LATE DAY AND EVENING. MARINE...NOW THROUGH SUNDAY NIGHT...THE SOUTHEAST WINDS WILL REMAIN LIGHT TO VARIABLE WITH LOW SEAS ACROSS THE GULF WATERS. THE MAIN CONCERNED THROUGH THE SHORT TERM WILL CONTINUE TO BE THE CONVECTION OVER THE GULF. THERE IS ENOUGH INSTABILITY IN THE AREA FROM A STATIONARY BOUNDARY PARALLEL TO THE COAST THAT WILL ENHANCE MORE CONVECTION INCREASING LATE THIS AFTERNOON AND CONTINUE OVERNIGHT. SUNDAY...THE POTENTIAL FOR CONVECTION WILL BEGIN TO DEVELOP IN THE AFTERNOON AND CONTINUE OVERNIGHT AS A COLD FRONT IS EXPECTED TO ARRIVED EARLY MONDAY INCREASING THE CHANCE OF RAIN EVEN MORE AND SHIFTING WINDS NORTHERLY. MONDAY THROUGH THURSDAY...COLD FRONT STILL ON TAP FOR EARLY MONDAY AS HIGH PRESSURE BUILDS DOWN THE CENTRAL PLAINS AS A MID LEVEL TROUGH DEEPENS INTO THE GULF SOUTH STATES. NORTHEAST WINDS INCREASE APPROACHING SMALL CRAFT ADVISORY CONDITIONS MONDAY AFTERNOON. SEAS TO RESPOND AND BUILD UPWARDS TO 6 FEET BY MONDAY NIGHT. MODERATE NORTHEAST TO EAST WINDS PERSIST TUESDAY AS THE FRONT BECOMES STATIONARY AND HIGH PRESSURE EXPANDS OVER THE CENTRAL GULF. A RETURN TO SOUTHEAST WINDS WEDNESDAY WITH A GRADUAL INCREASE THROUGH THE END OF THE WEEK IS EXPECTED. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MONDAY AND TUESDAY WITH DECREASING COVERAGE MID TO LATE WEEK. && .BRO WATCHES/WARNINGS/ADVISORIES...NONE. && THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE BROWNSVILLE TX 915 PM CDT SAT APR 18 2015 TXZ248>257-192100- ZAPATA-JIM HOGG-BROOKS-KENEDY-STARR-HIDALGO-INLAND WILLACY- INLAND CAMERON-COASTAL WILLACY-COASTAL CAMERON- 915 PM CDT SAT APR 18 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF DEEP SOUTH TEXAS. .DAY ONE...REST OF TONIGHT THERE IS A MODERATE RISK OF RIP CURRENTS AT THE BEACHES OF SOUTH PADRE ISLAND AND AT BOCA CHICA BEACH. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY SEVERE THUNDERSTORMS ARE POSSIBLE SUNDAY AND MONDAY DUE TO THE APPROACH AND PASSAGE OF A COLD FRONT. AN ELEVATED RISK OF RIP CURRENTS IS POSSIBLE AT THE LOCAL BEACHES MONDAY THROUGH WEDNESDAY. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED. GMZ130-132-135-150-155-170-175-192100- LAGUNA MADRE FROM THE PORT OF BROWNSVILLE TO THE ARROYO COLORADO- LAGUNA MADRE FROM THE ARROYO COLORADO TO 5 NM NORTH OF PORT MANSFIELD TX- LAGUNA MADRE FROM 5 NM NORTH OF PORT MANSFIELD TO BAFFIN BAY TX- COASTAL WATERS FROM PORT MANSFIELD TO THE RIO GRANDE OUT 20 NM- COASTAL WATERS FROM BAFFIN BAY TO PORT MANSFIELD OUT 20 NM- WATERS FROM PORT MANSFIELD TO THE RIO GRANDE EXTENDING FROM 20 TO 60 NM- WATERS FROM BAFFIN BAY TO PORT MANSFIELD EXTENDING FROM 20 TO 60 NM- 915 PM CDT SAT APR 18 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF THE GULF OF MEXICO AND THE LAGUNA MADRE. .DAY ONE...REST OF TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY SEVERE THUNDERSTORMS ARE POSSIBLE SUNDAY AND MONDAY DUE TO THE APPROACH AND PASSAGE OF A COLD FRONT. SMALL CRAFT ADVISORIES ARE POSSIBLE FOR THE LOWER TEXAS COASTAL WATERS MONDAY AND MONDAY NIGHT DUE TO STRONGER WINDS AND HIGHER SEAS. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED.
The Corpus Christi radar (KCRP), 195 km away, was scanning. The volume nearest the first event began at 02:20 UTC.
1 hail. Local standard time, as filed.
Zapata County Sheriffs Office reported quarter size hail near the city of Zapata.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Texas in 2015Every state in 2015This day in weather historyWarnings in Texas, April 2015
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 574018.