505
FXUS64 KBRO 240538 AAA
AFDBRO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1238 AM CDT THU SEP 24 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1237 AM CDT THU SEP 24 2026
- LOW TO MEDIUM (20-40%) RAIN CHANCES NEARLY EACH DAY TO CONTINUE
THROUGH EARLY NEXT WEEK ACROSS DEEP SOUTH TEXAS, MAINLY ALONG
THE SEA BREEZE.
- ABOVE AVERAGE TEMPERATURES (AROUND 5-10 DEGREES ABOVE NORMAL) TO
CONTINUE THROUGH THE END OF SEPTEMBER.
- WIDESPREAD MODERATE (LEVEL 2 OUT OF 4) TO MAJOR (LEVEL 3 OUT OF
4) HEAT RISK TO CONTINUE ACROSS THE REGION THROUGH WEDNESDAY OF
NEXT WEEK.
- 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 TUESDAY EVENING THROUGH THURSDAY TIMEFRAME.
DISCUSSION
ISSUED AT 1058 PM CDT WED SEP 23 2026
THE HEAT PUNCTUATED WITH NEAR DAILY CHANCES OF ISOLATED TO WIDELY
SCATTERED SHOWERS AND THUNDERSTORMS ALONG THE SEA BREEZE WILL
CONTINUE TO BE THE PRIMARY WEATHER FOCUS THROUGH THIS WEEK.
HOWEVER, THERE REMAIN SOME INDICATIONS OF A POTENTIAL WEATHER
PATTERN CHANGE THAT WILL FEATURE THINGS COOLING DOWN (SLIGHTLY)
MID TO LATE NEXT WEEK, OR AS WE CLOSE OUT THE MONTH OF SEPTEMBER
AND OPEN THE BOOKS TO OCTOBER. IT'S WORTH NOTING THAT
CLIMATOLOGICALLY OCTOBER IS ONE OF OUR FASTEST COOLING MONTHS
(WHERE OUR AVERAGE TEMPERATURES FALLS QUICKLY FROM THE BEGINNING
OF THE MONTH TO THE END OF THE MONTH).
THE POTENTIAL WEATHER PATTERN CHANGE MID TO LATE NEXT WEEK TO THE
COOLER SIDE WILL BE DRIVEN BY THE FLATTENING OF THE PERSISTENT
HEAT DOME THAT HAS PLAGUED THE REGION THIS SUMMER AND A SFC COOL
FRONT. IN ADDITION TO THE COOLER CHANGES, THIS WEATHER PATTERN
CHANGE WILL BE HIGHLIGHTED BY A POTENTIAL NOTABLE FLIP TO A
WETTER PATTERN MID TO LATE NEXT WEEK. IN FACT, DESPITE THE
ISOLATED TO WIDELY SCATTERED PRECIPITATION CHANCES THROUGH THIS
WEEK, OUR NEXT BEST, REAL, AND MORE WIDESPREAD CHANCE FOR SHOWERS
AND THUNDERSTORMS WILL COME MID TO LATE NEXT WEEK (I.E. IN THE
TUESDAY EVENING THROUGH THURSDAY TIMEFRAME). FORECAST MODELS AND
ENSEMBLES HAVE BEEN ADVERTISING THIS FOR THE PAST FEW DAYS NOW.
THIS ROUND OF SHOWERS AND THUNDERSTORMS TO COME NEXT WEEK WILL BE
ASSOCIATED WITH THE INTERACTIONS OF A NEARBY COOL FRONTAL
BOUNDARY, GULF MOISTURE, AND A NEARBY SHORTWAVE TROUGH.
THROUGH THE FORECAST PERIOD OR THROUGH NEXT WEEK, WE HAVE LOW-
MEDIUM (20-40%) CHANCES FOR RAIN. HAD TO LOWER THE POPS SOME OF
THIS WEEK AS THE NBM WAS RUNNING TOO HIGH, GIVEN THE FACT THAT WE
STILL ARE UNDER THE INFLUENCE OF A STRONG 591-594 DAM HEAT DOME
THAT WILL PLAY THE ROLE OF OFFSETTING ANY SHOWER OR THUNDERSTORM
ACTIVITY THROUGH THIS WEEK.
TEMPERATURE WISE, THROUGH THE REMAINDER OF THIS WEEK THROUGH
WEDNESDAY OF NEXT WEEK, FORECAST MODELS/ENSEMBLES CONTINUE TO
ADVERTISE THE PERSISTENT, STRONG, AND BROAD 591-594 MB HEAT DOME
OVER THE REGION. THIS WILL RESULT IN A CONTINUATION OF HOTTER THAN
NORMAL TEMPERATURES THROUGHOUT DEEP SOUTH TEXAS THROUGH NEXT
WEDNESDAY. HIGH TEMPERATURES THROUGH NEXT WEDNESDAY WILL RANGE
BETWEEN THE MID 90S TO LOWER 100S WITH THE HOTTEST TEMPERATURES
OCCURRING IN THE SUNDAY THROUGH TUESDAY OF NEXT WEEK TIMEFRAME.
WIDESPREAD MODERATE (LEVEL 2 OF 4) TO MAJOR (LEVEL 3 OF 4) WITH
POCKETS OF EXTREME (LEVEL 4 OF 4) HEAT RISK WILL BE COMMON THROUGH
NEXT WEDNESDAY BEFORE A REPRIEVE FROM THE HEAT TAKES PLACE NEXT
THURSDAY. DURING THIS TIME, PEAK HEAT INDICES WILL MAINLY RANGE
BETWEEN 100-110F DEGREES THROUGH THE FORECAST PERIOD.
AS FAR AS PRECIPITATION, ON A PERSISTENT EASTERLY FLOW PATTERN, LOW
TO MEDIUM (20-40%) CHANCES FOR SOME MUCH NEEDED RAINFALL IN THE FORM
OF ISOLATED TO WIDELY SCATTERED SHOWERS AND THUNDERSTORMS ALONG THE
SEA BREEZE IS POSSIBLE ACROSS DEEP SOUTH TEXAS AND THE RIO GRANDE
VALLEY NEARLY EACH DAY THROUGH EARLY NEXT WEEK.
ONCE WE GET INTO THE MID TO LATTER PARTS OF NEXT WEEK (IN THE
SEPTEMBER 30-OCTOBER 2) TIMEFRAME, THE PATTERN APPEARS TO BREAK
DOWN WITH A SFC COOL FRONT AND NEARBY SHORTWAVE TROUGH HELPING TO
IGNITE SHOWER AND THUNDERSTORM CHANCES. AGAIN, THIS APPEARS TO BE
OUR NEXT BEST AND MORE WIDESPREAD CHANCE FOR SOME VERY MUCH
NEEDED RAINFALL ACROSS DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY.
POPS ARE IN THE LOW- MEDIUM RANGE (30-40%) DURING THIS TIMEFRAME.
WE WILL CONTINUE TO KEEP CLOSE WATCH ON THIS POTENTIAL PATTERN
CHANGE TO COOLER AND WETTER MID TO LATE NEXT WEEK.
AVIATION
(06Z TAFS)
ISSUED AT 1237 AM CDT THU SEP 24 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 1058 PM CDT WED SEP 23 2026
GENERALLY, FAVORABLE MARINE CONDITIONS WILL PERSIST THROUGH THE
MIDDLE PARTS OF NEXT WEEK WITH LOW TO MODERATE SEAS (WAVE HEIGHTS
BETWEEN 1-3 FEET) AND WINDS. THERE COULD BE SOME SCEC CONDITIONS
THAT DEVELOP NEXT TUESDAY/WEDNESDAY. THERE WILL BE NEAR DAY-TO-DAY
CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH THE MIDDLE OF NEXT
WEEK. COVERAGE LOOKS TO BE ISOLATED TO SCATTERED FOR THE MOST PART.
OUR NEXT BEST AND MORE WIDESPREAD CHANCE FOR SHOWERS AND
THUNDERSTORMS WILL BE IN THE NEXT TUESDAY THROUGH THURSDAY TIMEFRAME.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 96 81 95 80 / 30 30 40 10
HARLINGEN 98 76 98 75 / 30 30 30 0
MCALLEN 99 79 99 78 / 40 20 30 10
RIO GRANDE CITY 97 77 99 76 / 40 20 20 10
SOUTH PADRE ISLAND 90 83 89 82 / 30 40 20 10
BAYVIEW/PORT ISABEL 94 79 94 79 / 30 30 20 10
BRO WATCHES/WARNINGS/ADVISORIES
NONE.
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