761
FXUS64 KBRO 250535 AAA
AFDBRO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1235 AM CDT FRI SEP 25 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1233 AM CDT FRI SEP 25 2026
- LOW TO MEDIUM (10-40%) RAIN CHANCES ALONG THE SEA BREEZE ON
FRIDAY ACROSS DEEP SOUTH TEXAS.
- ABOVE AVERAGE TEMPERATURES (AROUND 5-10 DEGREES ABOVE NORMAL) TO
CONTINUE THROUGH WEDNESDAY OF NEXT WEEK.
- WIDESPREAD MODERATE (LEVEL 2 OUT OF 4) TO MAJOR (LEVEL 3 OUT OF
4) HEAT RISK WITH POCKETS OF EXTREME (LEVEL 4 OF 4) HEAT RISK
TO CONTINUE ACROSS THE REGION THROUGH WEDNESDAY OF NEXT WEEK.
- HEAT SPIKES ARE POSSIBLE TUESDAY/WEDNESDAY OF NEXT WEEK WITH
DANGEROUS HEAT INDICES RANGING BETWEEN 105-115F DEGREES.
- A WELCOME WEATHER PATTERN CHANGE TO COOLER AND WETTER COULD
TAKE SHAPE AT THE START OF OCTOBER (SOMETIME MID TO LATE NEXT
WEEK).
- OUR NEXT BEST AND MORE WIDESPREAD CHANCES FOR RAIN (DUE TO A
COOL FRONT AND NEARBY SHORTWAVE TROUGH) WILL COME MID TO LATE
NEXT WEEK; CURRENTLY HAVE LOW-MEDIUM CHANCES (30-40%) AREAWIDE
IN THE WEDNESDAY THROUGH FRIDAY TIMEFRAME.
DISCUSSION
ISSUED AT 1113 PM CDT THU SEP 24 2026
THE HEAT WILL CONTINUE TO BE THE MAIN WEATHER STORYLINE THROUGH
WEDNESDAY OF NEXT WEEK. HOWEVER, WEDNESDAY THROUGH FRIDAY OF NEXT
WEEK (OR AS WE MOVE INTO THE MONTH OF OCTOBER), THE STORYLINE WILL
SHIFT TOWARDS THE INCREASING CHANCES FOR A SIGNIFICANT WEATHER
PATTERN CHANGE TOWARDS COOLER AND WETTER CONDITIONS, DRIVEN BY EL
NINO INFLUENCES.
WE START OFF THE FORECAST PERIOD TONIGHT WHERE MOST OF THE DIURNALLY
AND SEA BREEZE DRIVEN RAIN SHOWERS CONTINUE TO WANE ACROSS THE
REGION. CAN'T RULE OUT AN ISOLATED SHOWER OR TWO IS SPOTS TONIGHT.
THE REGION CONTINUES TO SIT ON THE SOUTHERN PERIPHERY OF A STRONG
AND BROAD 591-594 DAM SUB-TROPICAL HEAT DOME. THIS SETUP IS
HELPING DRIVE A PERSISTENT EASTERLY FLOW REGIME OVER THE REGION
WHICH IS HELPING TO DRIVE THE DAY-TO-DAY SEA BREEZE CONVECTION.
FRIDAY WILL PRESENT ANOTHER DAY AND OPPORTUNITY OF ISOLATED (HIT-
OR-MISS VARIETY) SEA BREEZE SHOWERS OVER THE REGION, PRIMARILY
DURING THE AFTERNOON INTO THE EARLY EVENING HOURS. CHANCES FOR
PRECIPITATION IS LOW-MEDIUM (10-40%) FOR FRIDAY.
SATURDAY THROUGH MONDAY OF NEXT WEEK, THE AFOREMENTIONED HEAT
DOME WILL STRENGTHEN AND EXPAND OVER THE REGION. DUE TO THE
GREATER INFLUENCES OF THE STRENGTHENING/EXPANDING HEAT DOME, RAIN
CHANCES WILL BE SUPPRESSED SATURDAY THROUGH MONDAY DUE TO
INCREASED SUBSIDENCE. THAT SAID, SATURDAY THROUGH MONDAY WILL
CONTINUE TO FEATURE HOTTER THAN NORMAL TEMPERATURES AND MOSTLY DRY
CONDITIONS.
TUESDAY THROUGH WEDNESDAY OF NEXT WEEK IS WHEN THINGS GET
INTERESTING REGARDING OUR AFOREMENTIONED PATTERN SHIFT. HURRICANE
POLO DURING THIS TIME IS EXPECTED TO MAKE LANDFALL OVER THE BAJA
PENINSULA OF CALIFORNIA AND MOVE INTO NORTHERN MEXICO. ALONG WITH
THE RE-CURVATURE OF HURRICANE POLO, DEEP TROPICAL MOISTURE FROM
THE EASTERN PACIFIC WILL STREAM WILL BEGIN TO STREAM INTO THE
REGION FROM THE WEST-SOUTHWEST. MEANWHILE, DEEP TROPICAL MOISTURE
FROM THE GULF OF AMERICA WILL BEGIN TO STREAM INTO THE REGION FROM
THE SOUTH, COURTESY OF A LARGE BERMUDA HIGH TO THE EAST. THE
COMBINATION OF DEEP TROPICAL MOISTURE STREAMING IN FROM THESE TWO
SOURCE REGIONS ALONG WITH THE AFOREMENTIONED HEAT DOME IN PLACE
(THOUGH WEAKENING) COULD RESULT IN A HEAT SPIKE WITH HIGH HEAT
INDICES TUESDAY AND WEDNESDAY. INCREASED HUMIDITY LEVELS WITH
DEWPOINTS IN THE MID TO UPPER 70S WILL RESULT IN A RETURN TO
DANGEROUS PEAK HEAT INDICES RANGING BETWEEN 105-113F DEGREES
TUESDAY AND WEDNESDAY. THIS WILL TRIGGER WIDESPREAD MAJOR (LEVEL 3
OF 4) TO EXTREME LEVEL 4 OF 4) HEAT RISK OVER THE REGION. SPECIAL
WEATHER STATEMENTS (SPSS) AND/OR A HEAT ADVISORY MAY BE NEEDED
TUESDAY AND WEDNESDAY.
DURING THIS TIME (TUESDAY THROUGH WEDNESDAY OF NEXT WEEK), A
SOUTHEASTWARD ADVANCING COOL FRONT WILL BE TRAVERSING ACROSS TEXAS
GRADUALLY APPROACHING DEEP SOUTH TEXAS. FURTHERMORE, THERE ARE
INDICATIONS OF A WEAK SHORTWAVE TROUGH AND MID-UPPER ENERGIES
RESIDING NEAR DEEP SOUTH TEXAS AND NORTHEAST MEXICO. THE
COMBINATION OF A NEARBY SHORTWAVE TROUGH, AN APPROACHING COOL
FRONT, AND THE INFLUX OF DEEP TROPICAL MOISTURE FROM THE GULF OF
AMERICA AND THE EASTERN EQUATORIAL PACIFIC OCEAN WILL SUPPORT
WIDESPREAD CHANCES FOR SHOWERS AND THUNDERSTORMS BEGINNING
WEDNESDAY AND PERSISTING THROUGH THEN END OF NEXT WEEK AND
POSSIBLY LONGER. THIS IS THE POTENTIAL PATTERN SHIFT THAT WE'RE
CLOSELY MONITORING AND IF REALIZED WILL BRING THE BREAKTHROUGH
RAINS THAT WE'VE BEEN WAITING FOR SO LONG AS WELL AS A NOTABLY
COOLER PATTERN DUE TO THE INCREASE CLOUD COVERAGE AND RAINS. THIS
POTENTIAL PATTERN SHIFT TO START OCTOBER HAS EL NINO WRITTEN ALL
OVER IT. AGAIN, WE WILL CONTINUE TO CLOSELY MONITOR FORECAST
TRENDS IN THE DAYS AHEAD. CURRENTLY, WE'VE MAINTAINED LOW-MEDIUM
(30-40%) POPS WEDNESDAY THROUGH FRIDAY AREAWIDE. IT'S TOO EARLY TO
GET INTO THE EXACT IMPACTS, BUT HEAVY RAINFALL IS POSSIBLE GIVEN
THE SURGE OF TROPICAL MOISTURE.
AVIATION
(06Z TAFS)
ISSUED AT 1233 AM CDT FRI SEP 25 2026
VFR WILL PREVAIL AT THE AERODROMES THROUGH THE NEXT 24 HOURS, WITH
LIGHT TO MODERATE WINDS AND CLEAR TO PARTLY CLOUDY SKIES. A TEMPO
FOR CONVECTION HAS BEEN ADDED TO THE TAFS, WITH TIMING BASED ON
THE HRRR MODEL.
MARINE
ISSUED AT 1113 PM CDT THU SEP 24 2026
GENERALLY, FAVORABLE MARINE CONDITIONS WILL PERSIST THROUGH MONDAY
OF NEXT WEEK WITH LOW TO MODERATE SEAS (WAVE HEIGHTS BETWEEN 1-3
FEET) AND WINDS. TUESDAY/WEDNESDAY AND POINTS FORWARD, CONDITIONS
WILL BECOME MORE ADVERSE DUE TO THE THREAT FOR SHOWERS AND
THUNDERSTORMS AS WELL AS SCEC CONDITIONS DEVELOPING.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 80 95 80 96 / 30 50 10 30
HARLINGEN 78 98 75 99 / 30 30 10 20
MCALLEN 79 98 78 99 / 20 40 10 20
RIO GRANDE CITY 77 98 76 101 / 20 30 10 10
SOUTH PADRE ISLAND 83 89 82 89 / 40 30 10 10
BAYVIEW/PORT ISABEL 80 94 78 94 / 30 30 10 20
BRO WATCHES/WARNINGS/ADVISORIES
NONE.
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