396
FXUS64 KBRO 010419
AFDBRO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1119 PM CDT WED SEP 30 2026
..NEW DISCUSSION, MARINE
KEY MESSAGES
UPDATED AT 1111 PM CDT WED SEP 30 2026
- WIDESPREAD MAJOR (LEVEL 3 OF 4) TO EXTREME (LEVEL 4 OF 4) HEAT
RISK EXPECTED ACROSS THE REGION THURSDAY.
- COOLER AND WETTER CONDITIONS ARE EXPECTED THURSDAY AFTERNOON
INTO EARLY NEXT WEEK DUE TO A FRONTAL PASSAGE AND A MULTI-DAY
RAINFALL EVENT.
- THE WEATHER PREDICTION CENTER (WPC) HAS DEEP SOUTH TEXAS UNDER
A SLIGHT (LEVEL 2 OF 4) TO MODERATE (LEVEL 3 OF 4) RISK FOR
FLOODING RAINFALL FOR THURSDAY, A MARGINAL (LEVEL 1 OF 4) TO
SLIGHT RISK ON FRIDAY, AND A MARGINAL RISK ALONG THE COAST ON
SATURDAY.
DISCUSSION
ISSUED AT 1111 PM CDT WED SEP 30 2026
HEAT WILL CONTINUE TO BE A CONCERN THURSDAY AFTERNOON, WITH HIGH
TEMPERATURES FORECAST TO RANGE FROM THE UPPER 90S TO JUST ABOVE
100. SOUTHEASTERLY WINDS WILL CONTINUE TO ADVECT ADDITIONAL
MOISTURE FROM THE GULF WILL SUPPORT DEWPOINTS IN THE UPPER 70S.
THE COMBINATION OF HOT TEMPERATURES AND HUMIDITY WILL LIKELY
SUPPORT PEAK HEAT INDICES RANGING FROM 105-114. HOWEVER,
INCREASING CLOUD COVER RAIN CHANCES THURSDAY AFTERNOON MAY
SUPPRESS TEMPERATURES AND HEAT INDICES, KEEPING CONFIDENCE LOW ON
ANY WIDESPREAD HEAT INDEX VALUES ABOVE 110 DEGREES. A HEAT
ADVISORY OR SPECIAL WEATHER STATEMENT MAY BE NEEDED THURSDAY
AFTERNOON.
HIRES MODELS SUPPORT THE DEVELOPMENT OF ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS ALONG THE SEA BREEZE EARLY THURSDAY
AFTERNOON. ADDITIONALLY, ENHANCED FORCING ALONG AN ADVANCING COLD
FRONT APPROACHING FROM THE NORTHWEST WILL LIKELY RESULT IN A LINE
OF SHOWERS AND THUNDERSTORMS DEVELOPING AHEAD OF THE FRONT AND
MOVING INTO THE AREA MID TO LATE AFTERNOON. CONVECTIVE MODELS
DEPICT THESE BOUNDARIES COLLIDING ROUGHLY ALONG I-69C/US-281 LATE
THURSDAY AFTERNOON OR EARLY THURSDAY EVENING. FROM THERE, THE
FORECAST BECOMES MORE UNCERTAIN, THOUGH CENTRAL AND WESTERN
PORTIONS OF THE CWA WILL LIKELY CONTINUE TO SEE SHOWERS AND
THUNDERSTORMS INTO FRIDAY MORNING. STRONG TO SEVERE THUNDERSTORMS
WILL BE POSSIBLE THURSDAY AFTERNOON, WITH THE PRIMARY HAZARDS
LIKELY TO BE DAMAGING WINDS AND HEAVY RAINFALL. THE STORM
PREDICTION CENTER HAS A MARGINAL RISK (LEVEL 1 OF 5) FOR SEVERE
WEATHER ROUGHLY ALONG AND WEST OF I-69C THURSDAY AND THURSDAY
NIGHT.
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS IS LIKELY FRIDAY
AFTERNOON THROUGH SATURDAY MORNING, AS THE COLD FRONT MOVES
THROUGH THE AREA. IN THE WAKE OF THE FRONT, AN OVERRUNNING PATTERN
LOOKS TO SET UP AS SOUTHEASTERLY MID-LEVEL FLOW CONTINUES TO
ADVECT WARM MOIST AIR FROM THE GULF INTO THE REGION. THIS WILL
LIKELY SUPPORT WIDESPREAD STRATIFORM RAIN, WITH GENERALLY LIGHT TO
MODERATE RAINFALL ACROSS MUCH OF THE AREA, THOUGH SOME HEAVIER
BANDS MAY DEVELOP, ESPECIALLY ALONG THE COAST.
WIDESPREAD RAINFALL AMOUNTS OF 2 TO 4 INCHES ARE POSSIBLE THROUGH
SATURDAY MORNING, WITH LOCALLY HIGHER AMOUNTS UP TO 6 INCHES
POSSIBLE. DEEP TROPICAL MOISTURE, WITH PWAT VALUES RANGING FROM
2-2.5 INCHES AND AMPLE INSTABILITY COULD RESULT IN HIGHER RAIN
RATES AND FLASH FLOODING.
THE WEATHER PREDICTION CENTER HAS ZAPATA, JIM HOGG, STARR, AND
WESTERN PORTIONS OF BROOKS COUNTIES IN A MODERATE RISK (LEVEL 3 OF
4) OF EXCESSIVE RAINFALL THURSDAY. THE REMAINDER OF DEEP SOUTH
TEXAS, EXCEPT FOR EASTERN PORTIONS OF CAMERON COUNTY, ARE UNDER A
SLIGHT RISK (LEVEL 2OF 4) FOR EXCESSIVE RAINFALL THURSDAY, WITH
EASTERN CAMERON COUNTY UNDER A MARGINAL RISK (LEVEL 1 OF 4).
ZAPATA, STARR, JIM HOGG AND WESTERN PORTIONS OF BROOKS AND HIDALGO
COUNTIES REMAIN UNDER A SLIGHT RISK FOR EXCESSIVE RAINFALL FRIDAY
WITH THE REST OF DEEP SOUTH TEXAS UNDER A MARGINAL RISK FOR
EXCESSIVE RAINFALL.
AVIATION
(00Z TAFS)
ISSUED AT 641 PM CDT WED SEP 30 2026
PREDOMINANTLY VFR CONDITIONS ARE FORECAST TO CONTINUE THROUGH
THURSDAY MORNING. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
ARE POSSIBLE THURSDAY AFTERNOON, WHICH MAY RESULT IN MVFR TO IFR
CONDITIONS IF ANY CONVECTION MOVES OVER AN AIRFIELD. TOWARDS THE
END OF THE PERIOD, THERE IS A LOW POTENTIAL FOR A LINE OF
THUNDERSTORMS TO APPROACH OR MOVE THROUGH THE AREA.
WINDS ARE FORECAST TO REMAIN SOUTHEASTERLY THROUGH THE PERIOD.
WIND GUSTS ARE FORECAST TO DIMINISH OVERNIGHT, BEFORE RETURNING
LATE THURSDAY MORNING.
MARINE
ISSUED AT 1111 PM CDT WED SEP 30 2026
WINDS AND SEAS ALONG THE LOWER TEXAS COAST ARE FORECAST TO REMAIN
ELEVATED THURSDAY, WITH SMALL CRAFT SHOULD EXERCISE CAUTION
HEADLINES LIKELY NEEDED THROUGH THE DAY. CONDITIONS LOOK TO
IMPROVE FRIDAY MORNING, WITH A COLD FRONT FORECAST TO MOVE
THROUGH THE AREA FRIDAY EVENING. LIGHT NORTHEASTERLY WINDS BEHIND
THE FRONT WILL LIKELY LOWER SEAS THROUGH THE WEEKEND.
RAIN CHANCES ARE FORECAST TO INCREASE THURSDAY AFTERNOON, WITH
WIDESPREAD RAINFALL LIKELY THROUGH THE WEEKEND.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 83 97 80 94 / 20 30 60 80
HARLINGEN 79 99 77 96 / 20 50 50 90
MCALLEN 83 102 79 95 / 20 50 80 90
RIO GRANDE CITY 81 102 76 92 / 30 70 90 90
SOUTH PADRE ISLAND 84 90 82 89 / 20 20 50 60
BAYVIEW/PORT ISABEL 81 95 79 92 / 20 30 50 80
BRO WATCHES/WARNINGS/ADVISORIES
TX...NONE.
GM...NONE.
SHORT TERM...60-BE
LONG TERM....60-BE
AVIATION...60
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