454
FXUS64 KBRO 182317 AAA
AFDBRO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
617 PM CDT FRI SEP 18 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 615 PM CDT FRI SEP 18 2026
- THERE IS MODERATE (LEVEL 2 OF 4) HEAT RISK THIS AFTERNOON. HEAT
INDICES COULD CLIMB OVER 108 ACROSS THE RIO GRANDE VALLEY AND
COASTAL COUNTIES FOR AN HOUR OR TWO THIS AFTERNOON.
- LOW TO MODERATE (20 TO 50%) CHANCE OF SHOWERS AND THUNDERSTORMS
CONTINUE ACROSS DEEP SOUTH TEXAS THIS AFTERNOON, BEFORE
CONDITIONS DRY OUT TOMORROW FOR THE WEEKEND.
- RAIN CHANCES RETURN EARLY NEXT WEEK AND CONTINUE THROUGHOUT THE
WEEK. HEAT RISK WILL CONTINUE AS WELL.
- THERE IS A MODERATE RISK OF RIP CURRENTS AT AREA BEACHES.
DISCUSSION
ISSUED AT 1210 PM CDT FRI SEP 18 2026
AN UNSETTLED WEATHER PATTERN CONTINUES OVER THE NEXT FEW DAYS AS AN
AREA OF STRONG HIGH PRESSURE OVER THE SOUTHEASTERN CONUS CONTINUES
TO BACKBUILD WESTWARD, WITH NORTHEASTERLY UPPER LEVEL FLOW BENEATH
THE UNDERSIDE OF OF THIS HIGH REACHING DEEP SOUTH TEXAS. BECAUSE
THIS NORTHEASTERLY AIRMASS HAS SPEND CONSIDERABLE TIME OVER THE
GULF, THE ATMOSPHERIC PROFILE IS EXPECTED TO REMAIN CONSIDERABLY
MOIST THIS AFTERNOON, WITH PWATS OVER 2 INCHES. THIS WILL SUPPORT
LOW TO MODERATE (20 TO 50%) RAIN CHANCES THIS AFTERNOON. THE RAIN IS
EXPECTED TO BE OVERALL BENEFICIAL, WITH MOST AREAS RECEIVING NO MORE
THAN HALF AN INCH. HOWEVER, SOME HEAVIER SHOWERS AND THUNDERSTORMS
COULD CAUSE LOCALLY HEAVIER AMOUNTS WITH THE POTENTIAL FOR NUISANCE
PONDING.
AS HIGH PRESSURE CONTINUES TO BUILD WESTWARD OVER NORTHEASTERN TEXAS
THOUGH THE WEEKEND, UPPER-LEVEL SUBSIDENCE WILL KEEP CONDITIONS DRY
FOR THE WEEKEND. A SHOWER OR TWO CANNOT BE COMPLETELY RULED OUT
ALONG THE SEA BREEZE, BUT RAIN CHANCES REMAIN VERY LOW FOR BOTH
SATURDAY AND SUNDAY.
RAIN CHANCES ARE EXPECTED TO PICK UP AGAIN NEXT WEEK AS MORE MOIST
AIR IS ADVECTED INTO THE REGION AS NORTHEASTERLY FLOW CONTINUES.
SEA BREEZE ACTIVITY IS POSSIBLE EACH DAY NEXT WEEK. HOWEVER,
LONGER-RANGE GUIDANCE IS NOT IN AGREEMENT AS TO WHETHER THE UPPER
LEVEL RIDGE OVER NORTHEAST TEXAS IS GOING TO CONTINUE THROUGH
NEXT WEEK, OR BEGIN TO BREAK DOWN AS A TROUGH APPROACHES FROM THE
WEST. WHILE THE CURRENT NBM GUIDANCE IS SUPPORTING LOW TO MODERATE
(20 TO 40%) POPS STARTING TUESDAY, THIS COULD TREND HIGHER OR
LOWER DEPENDING ON THE BEHAVIOR OF THE HIGH PRESSURE SYSTEM AND
THE TROUGH TO OUR WEST. CHANCES COULD DECREASE IF THE HIGH
PRESSURE STAYS STRONGER OVER TEXAS, BUT WE COULD SEE AN INCREASE
IN WIDESPREAD RAIN CHANCES IF THE APPROACHING TROUGH IS ABLE TO
BREAK DOWN THE RIDGE AND PRODUCE ANY SHORTWAVE DISTURBANCES AS IT
APPROACHES.
HEAT RISK WILL REMAIN A CONCERN OVER THE NEXT WEEK. THOUGH
INCREASED CLOUD COVER AND RAIN CHANCES MAY BRING SOME SMALL
TEMPERATURE RELIEF BY A FEW DEGREES, THE HUMID AIRMASS WILL
CONTINUE TO KEEP HEAT INDICES HIGH. HEAT INDICES WILL BE ELEVATED
TODAY, WITH SOME AREAS EXCEEDING 108 DEGREES FOR AN HOUR OR TWO
THIS AFTERNOON. WE WILL LIKELY SEE MORE ELEVATED HEAT INDICES THIS
WEEKEND AS WELL.
THERE IS A MODERATE RISK OF RIP CURRENTS AT AREA BEACHES TODAY.
AVIATION
(00Z TAFS)
ISSUED AT 615 PM CDT FRI SEP 18 2026
VFR CONDITIONS CONTINUE AS GENTLE TO MODERATE EAST-NORTHEASTERLY
WINDS BECOME LIGHT AND/OR VARIABLE TONIGHT BEFORE RETURNING BY
EARLY TO LATE AFTERNOON TOMORROW.
MARINE
ISSUED AT 1210 PM CDT FRI SEP 18 2026
FAVORABLE CONDITIONS ARE EXPECTED OVER THE NEXT SEVERAL DAYS WITH
LIGHT TO MODERATE NORTHEASTERLY WINDS AND LOW TO MODERATE (2-4 FEET)
WAVE HEIGHTS. OFFSHORE SHOWERS AND THUNDERSTORMS ARE POSSIBLE
THROUGHOUT NEXT WEEK, WHICH COULD TEMPORARILY DETERIORATE
CONDITIONS IN THEIR IMMEDIATE VICINITY.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 79 96 79 97 / 0 10 0 10
HARLINGEN 76 99 74 100 / 0 10 0 20
MCALLEN 79 101 78 103 / 0 10 0 10
RIO GRANDE CITY 78 102 77 102 / 10 0 0 0
SOUTH PADRE ISLAND 81 89 81 89 / 20 20 0 0
BAYVIEW/PORT ISABEL 78 95 77 95 / 10 10 0 10
BRO WATCHES/WARNINGS/ADVISORIES
TX...NONE.
GM...NONE.
SHORT TERM...55-MM
LONG TERM....55-MM
AVIATION...65-IRISH
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