488
FXUS64 KBRO 291126 AAA
AFDBRO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
526 AM CST SAT NOV 29 2025
..NEW AVIATION
KEY MESSAGES
UPDATED AT 513 AM CST SAT NOV 29 2025
* BREEZY SOUTHEASTERLY WINDS 15-25 MPH WITH HIGHER GUSTS TO CONTINUE
THROUGH SATURDAY.
* A BRIEF WARM SPIKE TAKES PLACE ON SATURDAY WITH HIGHS IN THE 80S.
* BIG CHANGES TO THE WEATHER PATTERN AS A STRONG COLD FRONT SATURDAY
NIGHT INTO SUNDAY WILL BRING A NOTABLY COOLER AIRMASS (POTENTIALLY
THE COLDEST SINCE LAST FEBRUARY) TO THE REGION SUNDAY THROUGH
EARLY NEXT WEEK.
* ADVERSE TO DANGEROUS SURF AND BOATING CONDITIONS ARE EXPECTED TO
PERSIST THROUGH AT LEAST SUNDAY IN RESPONSE TO AN ENHANCED
PRESSURE GRADIENT AND A STRONG COLD FRONT.
* RAIN CHANCES INCREASE INLAND SATURDAY NIGHT THROUGH MONDAY AND
AGAIN WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. GREATEST CHANCES
SUNDAY THROUGH SUNDAY NIGHT. RAIN CHANCES NEARLY EVERYDAY
THROUGH NEXT WEEK FOR THE GULF WATERS.
DISCUSSION
ISSUED AT 1103 PM CST FRI NOV 28 2025
A STRONG EARLY SEASON COLD FRONT THAT PROMISES TO BRING THE
COLDEST AIRMASS YET OF THE SEASON (COLDEST SINCE LAST FEBRUARY)
AND AN UNSETTLED WEATHER PATTERN WILL BE THE MAIN HIGHLIGHTS
THROUGH THE FORECAST PERIOD.
THE LATEST SATELLITE AND RADAR DATA DEPICTS SCATTERED TO OVERCAST
SKY COVERAGE WITH SOME LIGHT STREAMER SHOWERS DRIVEN BY BREEZY
SOUTHERLY GRADIENT WINDS AND A WEAK SHORTWAVE OVER THE SIERRA MADRE.
THROUGH TONIGHT, EXPECT FOR LIGHT STREAMER SHOWERS TO CONTINUE
ACROSS PARTS OF THE AREA WITH THE BEST CHANCE OF SHOWERS OCCURRING
CLOSER TO THE COAST.
WARM AIR ADVECTION (WAA) REGIME WILL CONTINUE ON SATURDAY AND
WILL RESULT IN WARM SPIKE, ALBEIT BRIEF. BREEZY SOUTHERLY WINDS
15-25 MPH WITH HIGHER GUSTS WILL AIDE IN DAYTIME HIGH TEMPERATURES
CLIMBING INTO THE MID TO UPPER 80S ON SATURDAY. HOWEVER, DURING
THE DAY ON SATURDAY, A STRONG SOUTH-SOUTHEASTWARD ADVANCING COLD
FRONT WILL BE SWEEPING ITS WAY THROUGH THE STATE OF TEXAS. THIS
COLD FRONT WILL BE ASSOCIATED WITH A HIGHLY AMPLIFIED AND ACTIVE
LARGE- SCALE PATTERN FEATURING A MILD WEST U.S. VS A COLD AND
WINTRY CENTRAL AND EAST U.S. IN WHICH FORECAST MODELS HAVE BEEN
ADVERTISING FOR THE PAST SEVERAL DAYS. WHILE THIS WILL BRING
PLENTY OF WINTRY WEATHER ACROSS THE NORTHERN TIER STATES, THIS
COLD FRONT WILL BRING MARKEDLY COOLER TEMPERATURES TO DEEP SOUTH
TEXAS AND THE RIO GRANDE VALLEY LATE THIS WEEKEND INTO THE EARLY
PARTS OF NEXT WEEK. THERE STILL REMAINS SOME DISCREPANCIES AMONGST
FORECAST GUIDANCES ON THE PRECISE TIMING AND STRENGTH OF THE COLD
FROPA, WHICH WOULD IMPACT HIGH TEMPS ON SUNDAY AND POTENTIALLY
BEYOND. TYPICALLY, THESE COLD SHALLOW AIRMASSES TEND TO BE
STRONGER AND HAVE A FASTER TIMING THAN THAN WHAT MOST GLOBAL
FORECAST MODELS SUGGEST. THE HI-RES, CAM NORTH AMERICA MODEL (NAM)
CAPTURES THESE TRENDS BETTER.
THAT SAID, IT STILL APPEARS THAT SOMETIME SATURDAY NIGHT INTO
SUNDAY, THIS STRONG COLD FRONT WITH ARCTIC ORIGINS WILL SWEEP
THROUGH ALL OF DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY. IN IT'S
WAKE WILL BE THE COLDEST AIRMASS OF THE SEASON SEEN SO FAR (SINCE
LAST FEBRUARY). HIGH TEMPERATURES ON SUNDAY WILL LIKELY BE REACHED
EARLY IN THE DAY AS TEMPERATURES ARE EXPECTED TO FALL THROUGH THE
DAY. HIGH TEMPERATURES FROM SATURDAY TO SUNDAY WILL BE 10-15 F
DEGREES COOLER, HOWEVER CLOSER TO SEASONABLE NORMS WITH VALUES ON
SUNDAY IN THE LOW TO MID 70S AND 60S OVER BRUSH COUNTRY.
CLEARING SKIES AMID ADDITIONAL COLD AND DRY AIR ADVECTION WILL
RESULT IN A NOTICEABLY CHILLY SUNDAY NIGHT AS OVERNIGHT LOW
TEMPERATURES ARE EXPECTED TO PLUNGE INTO THE 40S MOST PLACES, SOME
15F DEGREES OR SO COOLER THAN SATURDAY NIGHT, AND SOME 10F DEGREES
COOLER THAN NORMAL. A FULL COLD AND DRY AIR ADVECTION REGIME WILL BE
IN PLACE BY MONDAY. THIS COMBINED WITH A MODIFIED 1020-1025 MB SFC
ARCTIC HIGH PRESSURE SYSTEM OVER THE REGION WILL RESULT IN CONTINUED
COOLER THAN NORMAL TEMPERATURES WITH HIGH TEMPERATURES FAILING TO
MAKE IT OUT OF THE 50S ON MONDAY AND 60S ON TUESDAY. CLEAR SKIES AND
ADDITIONAL RADIATIONAL COOLING WILL RESULT IN OVERNIGHT LOW
TEMPERATURES MONDAY AND TUESDAY NIGHTS HOLDING IN THE 40S MOST
PLACES (50S ALONG THE RGV AND IMMEDIATE COAST), WHICH AGAIN WILL BE
WELL BELOW NORMAL LEVELS.
IN ADDITION TO THE COOLER CHANGES, THE PATTERN WILL BECOME UNSETTLED.
RAIN SHOWERS (SOME PERHAPS STRATIFORM TYPE) ARE POSSIBLE SATURDAY
NIGHT THROUGH MONDAY IN RESPONSE AND CONNECTION TO THE COLD
FRONTAL BOUNDARY. CURRENTLY, WE STILL HAVE LOW TO MEDIUM (20-60%)
POPS OVER DEEP SOUTH TEXAS DURING THIS TIME PERIOD WITH THE BEST
CHANCES BEING NEAR THE COAST. SUNDAY-SUNDAY NIGHT IS WHERE WE
EXPECT THE MOST WIDESPREAD COVERAGE. WE'VE MAINTAINED CATEGORICAL
POPS ALONG AND EAST OF IH-69C SUNDAY-SUNDAY NIGHT. EVEN GREATER
CHANCES WILL TAKE PLACE OVER THE OPEN GULF WATERS DURING THIS SAME
TIME PERIOD. RAIN SHOWERS ARE ALSO POSSIBLE OVER THE GULF WATERS
FRIDAY NIGHT AND SATURDAY IN CONNECTION TO THE AFOREMENTIONED WARM
FRONT AND AGAIN MONDAY NIGHT OF NEXT WEEK.
ANOTHER BOUT OF UNSETTLED WEATHER IS EXPECTED TO DEVELOP OVER THE
FORECAST AREA AS A NEARBY SHORTWAVE TROUGH/DEVELOPING LOW PRESSURE
SYSTEM WILL INCREASE THE THREAT FOR SHOWERS AND THUNDERSTORMS
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. CURRENTLY, WE HAVE LOW TO
MEDIUM (20-50%) CHANCES ACROSS DEEP SOUTH TEXAS WITH THE HIGHER
CHANCES LOCATED NEAR THE COAST.
TEMPERATURES WILL GRADUALLY MODERATE THROUGH THE WEEK, HOWEVER,
THE COMBINATION OF RAIN CHANCES AND INCREASED CLOUD COVERAGE WILL
LIMIT WARMING POTENTIAL. THAT SAID, HIGH TEMPERATURES BY WEDNESDAY
ARE PROGGED TO REACH THE 70S ACROSS MUCH OF DEEP SOUTH TEXAS.
HIGHS MAINLY IN THE 70S ARE THEN EXPECTED TO PERSIST THROUGH NEXT
SATURDAY. OVERNIGHT LOWS WEDNESDAY THROUGH SATURDAY NIGHT WILL
MAINLY BE IN THE 50S. GIVEN THE EXPLANATION ABOVE ABOUT MODEL
BIASES AND AFTER COLLABORATION WITH NEIGHBORING OFFICES, HAVE
DECIDED TO USE A BLEND OF THE NBM 25TH PERCENTILE AND NAM12 SUNDAY
THROUGH WEDNESDAY.
AVIATION
(12Z TAFS)
ISSUED AT 513 AM CST SAT NOV 29 2025
VFR CONDITIONS TO PERSIST THROUGH THE DURATION OF THE TAF CYCLE AT
ALL TAF SITES. SOUTHEASTERLY WINDS WILL BE PRESENT FOR THE TAF
CYCLE WITH SOME GUSTS DURING THE DAY AROUND 20 KNOTS. HOWEVER IT
POSSIBLE THAT SOME GUSTS COULD EVEN BE HIGHER. THE WIND GUSTS
SHOULD WEAKEN LATER THIS EVENING.
MARINE
ISSUED AT 1103 PM CST FRI NOV 28 2025
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE LAGUNA MADRE AND
THE GULF WATERS THROUGH SATURDAY EVENING DUE TO CONTINUED BREEZY
SOUTHEASTERLY WINDS. A SECOND, STRONGER COLD FRONT WILL SWEEP
THROUGH THE REGION SATURDAY NIGHT INTO SUNDAY. THIS WILL RESULT IN
CONTINUED ADVERSE TO HAZARDOUS MARINE CONDITIONS TO PERSIST AND A
SMALL CRAFT EXERCISE CAUTION OR SMALL CRAFT ADVISORY MAY BE
NEEDED THROUGH AT LEAST SUNDAY. MARINE CONDITIONS COULD IMPROVE BY
TUESDAY NIGHT WITH LOW TO MODERATE WINDS AND SEAS PREVAILING
THROUGH NEXT WEEK.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 83 67 75 49 / 10 20 80 70
HARLINGEN 85 61 69 48 / 10 20 70 60
MCALLEN 87 63 69 49 / 0 10 60 50
RIO GRANDE CITY 87 58 67 48 / 0 10 40 50
SOUTH PADRE ISLAND 80 71 74 56 / 10 30 80 80
BAYVIEW/PORT ISABEL 83 64 73 50 / 10 30 80 70
BRO WATCHES/WARNINGS/ADVISORIES
TX...HIGH RIP CURRENT RISK THROUGH THIS AFTERNOON FOR TXZ451-454-455.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR GMZ130-132-
135-150-155-170-175.
SHORT TERM...23
LONG TERM....23
AVIATION...64-KATZ
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