464
FXUS64 KBRO 282338 AAA
AFDBRO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
638 PM CDT MON SEP 28 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 629 PM CDT MON SEP 28 2026
- HOTTER THAN NORMAL TEMPERATURES WILL CONTINUE THROUGH THURSDAY.
- WIDESPREAD MAJOR (LEVEL 3 OUT OF 4) HEAT RISK WITH POCKETS OF
EXTREME (LEVEL 4 OF 4) HEAT RISK TO CONTINUE ACROSS THE REGION
THROUGH THURSDAY.
- HEAT SPIKES ARE POSSIBLE TUESDAY-THURSDAY WITH DANGEROUS HEAT
INDICES RANGING BETWEEN 105-115F DEGREES; SPECIAL WEATHER
STATEMENTS (SPSS) AND HEAT ADVISORIES MAY BE NEEDED.
- CONFIDENCE IS INCREASING ON A SIGNIFICANT WEATHER PATTERN
CHANGE TOWARDS MARKEDLY COOLER AND WETTER CONDITIONS LATER
THIS WEEK; THIS INCLUDES A MULTI-DAY HEAVY RAIN AND FLASH FLOOD
POTENTIAL THURSDAY THROUGH EARLY NEXT WEEK.
- PRELIMINARY RAINFALL AMOUNTS OF 2-4 INCHES WITH LOCALLY HIGHER
AMOUNTS IS POSSIBLE THURSDAY THROUGH SUNDAY NIGHT.
- THE WEATHER PREDICTION CENTER (WPC) HAS ALL OF DEEP SOUTH TEXAS
UNDER A SLIGHT (LEVEL 2 OF 4) RISK FOR EXCESSIVE RAINFALL FOR
THURSDAY, AND A MARGINAL TO SLIGHT (1 TO 2 OF 4) RISK FRIDAY.
- BREEZY SOUTHEAST WINDS 15-25 MPH WITH GUSTS UP TO 35 MPH OR SO
WILL RESULT IN SCEC TO SMALL CRAFT ADVISORIES FOR THE LAGUNA
MADRE AND THE GULF TUESDAY AND WEDNESDAY AS WELL AS INCREASED
RIP CURRENT RISKS ALONG THE BEACHES.
DISCUSSION
ISSUED AT 212 PM CDT MON SEP 28 2026
HOT AND HUMID CONDITIONS CONTINUE THROUGH THURSDAY AS RIDGING
REMAINS IN PLACE ACROSS DEEP SOUTH TEXAS. AFTERNOON HEAT INDICES
WILL REMAIN IN THE TRIPLE DIGITS, POTENTIALLY EXCEEDING 111 DEGREES
FOR BRIEF PERIODS. HEAT ADVISORIES AND/OR SPSS ARE POSSIBLE DAILY
THROUGH THURSDAY. INCREASING MOISTURE AND CLOUD COVER AHEAD OF AN
APPROACHING FRONT WILL LIMIT TEMPERATURES LATER IN THE WEEK, WITH
HIGHS IN THE 90S (AND WILL LIKELY END MCALLEN'S RECORD-BREAKING 100+
DEGREE DAY STREAK).
THE PATTERN WILL BECOME INCREASINGLY UNSETTLED LATE THIS WEEK INTO
THE WEEKEND AS TROUGHING OVER SW US INGESTS DEEP TROPICAL
MOISTURE FROM THE PACIFIC. AS THE TROUGH TRAVERSES EAST, THE
ASSOCIATED COLD FRONT IS EXPECTED TO STALL OVER CENTRAL TX
MIDWEEK, WHILE PERSISTENT SOUTHERLY TO SOUTHEASTERLY FLOW
TRANSPORTS ADDITIONAL GULF MOISTURE INTO THE REGION. PWAT VALUES
COULD REACH 2.3-2.6" LATER THIS WEEK, NEAR CLIMATOLOGICAL MAXIMUM
VALUES FOR EARLY OCTOBER, SUPPORTING EFFICIENT RAINFALL RATES IN
ANY SHOWERS.
AS THE FRONT SLOWLY MOVES SOUTHEAST, RAIN CHANCES INCREASE LATE
THURSDAY FROM WEST TO EAST, PEAKING ACROSS THE CWA FRIDAY
(70-90%), AND CONTINUING THROUGH THE WEEKEND WITH WIDESPREAD
MODERATE TO HIGH POPS (50-70%). THERE IS STILL UNCERTAINTY IN THE
EVOLUTION OF THIS SYSTEM, AS MODEL GUIDANCE CONTINUES TO DIFFER
ON THE TIMING AND PLACEMENT OF HEAVIEST RAINFALL. AT THIS TIME,
THE AXIS OF HEAVIEST RAINFALL LOOKS TO BE TO OUR NORTH. THE
OVERALL SIGNAL FOR A WETTER PATTERN HAS REMAINED CONSISTENT, BUT
THE LOCATION OF HEAVIER RAINFALL IN DEEP S TX WILL DEPEND ON WHERE
SLOW-MOVING OR TRAINING CONVECTION DEVELOPS.
EARLY ESTIMATE RAINFALL TOTALS FOR THURSDAY TO SUNDAY ARE AROUND
2- 4 INCHES, WITH THE HIGHEST TOTALS EXPECTED ACROSS WESTERN
PORTIONS OF DEEP S TX. LOCALLY HIGHER AMOUNTS CANNOT BE RULED OUT,
AND ANY SLOW-MOVING OR TRAINING SHOWERS AND THUNDERSTORMS COULD
PRODUCE LOCALLY HEAVY RAINFALL. THIS RAINFALL WILL BE BENEFICIAL
GIVEN ONGOING DROUGHT CONDITIONS, BUT RUNOFF AND FLASH FLOODING
COULD OCCUR, PARTICULARLY IN LOW-LYING, POOR DRAINAGE, AND URBAN
AREAS. GUIDANCE WILL CONTINUE TO BE MONITORED CLOSELY AS THE EVENT
APPROACHES AND THE TIMING AND RAINFALL AXIS BECOME BETTER
DEFINED.
THE WEATHER PREDICTION CENTER HAS HIGHLIGHTED THE REGION FOR AN
INCREASED RISK OF EXCESSIVE RAINFALL, WITH A SLIGHT RISK THURSDAY,
AND A MARGINAL (COAST) TO SLIGHT RISK (EAST OF I-69E) FRIDAY.
LOCAL BEACHES WILL REMAIN RELATIVELY PLEASANT TODAY AND MUCH OF
TOMORROW, BUT WILL DETERIORATE AS THE FRONT APPROACHES. INCREASING
WAVE HEIGHTS AND STRONGER ONSHORE FLOW WILL BRING AN INCREASED RISK
OF LIFE-THREATENING RIP CURRENTS, WITH MINOR COASTAL FLOODING ALSO
POSSIBLE AROUND HIGH TIDE TUESDAY NIGHT THROUGH THE WEEKEND.
AVIATION
(00Z TAFS)
ISSUED AT 629 PM CDT MON SEP 28 2026
VFR CONDITIONS ARE FORECAST TO CONTINUE THROUGH THE PERIOD. WINDS
ARE FORECAST TO BECOME LIGHT AND VARIABLE OVERNIGHT, THEN INCREASE
OUT OF THE SOUTHEAST TUESDAY AFTERNOON. THERE IS A LOW (10-20%) CHANCE
FOR ISOLATED CONVECTION ALONG THE SEA BREEZE TUESDAY AFTERNOON.
MARINE
ISSUED AT 212 PM CDT MON SEP 28 2026
GENTLE TO MODERATE SOUTH-SOUTHEASTERLY FLOW WITH SLIGHT SEAS PREVAIL
THROUGH TUESDAY. AN INCREASING PRESSURE GRADIENT WILL DEGRADE
CONDITIONS BY MIDWEEK, WITH SMALL CRAFT ADVISORY CONDITIONS POSSIBLE
AS EARLY AS TUESDAY NIGHT WITH SEAS BUILDING TO 4-7 FT. UNFAVORABLE
MARINE CONDITIONS WILL CONTINUE THROUGH THURSDAY. LOW RAIN CHANCES
(20-30%) ALSO CONTINUE THROUGH THURSDAY, INCREASING TO MODERATE-HIGH
(60-80%) THURSDAY NIGHT BEHIND THE FRONT, PERSISTING THROUGH THE
REMAINDER OF THE PERIOD. UNDER ANY THUNDERSTORMS, EXPECT LOCALLY
HIGHER WINDS AND SEAS.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 80 97 82 98 / 20 20 10 10
HARLINGEN 76 100 80 101 / 10 20 10 10
MCALLEN 80 102 82 103 / 10 10 20 0
RIO GRANDE CITY 78 103 80 104 / 0 0 0 0
SOUTH PADRE ISLAND 82 90 83 90 / 20 20 10 10
BAYVIEW/PORT ISABEL 78 95 80 96 / 10 20 10 10
BRO WATCHES/WARNINGS/ADVISORIES
TX...NONE.
GM...NONE.
SHORT TERM...69
LONG TERM....69
AVIATION...60-BE
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