634
FXUS64 KBRO 052007
AFDBRO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
307 PM CDT MON OCT 5 2026
..NEW DISCUSSION, MARINE
KEY MESSAGES
UPDATED AT 301 PM CDT MON OCT 5 2026
- THE NATIONAL HURRICANE CENTER (NHC) INDICATES A MEDIUM (40%) OF
TROPICAL DEVELOPMENT OF A LOW PRESSURE SYSTEM, CURRENTLY
SITUATED OVER THE SOUTHWESTERN GULF, THROUGH THE NEXT 48 HOURS
AND A HIGH (80%) CHANCE OF TROPICAL DEVELOPMENT THROUGH THE 7
DAY FORECAST.
- THE GREATEST IMPACTS ARE LIKELY TO BE AN ONGOING COASTAL
FLOODING AND RIP CURRENT THREAT, THOUGH ADDITIONAL HEAVY RAIN
IS POSSIBLE FROM THE STRENGTHENING SYSTEM OVER THE GULF.
- THE WEATHER PREDICTION CENTER (WPC) CONTINUES A MARGINAL RISK
OF ISOLATED FLASH FLOODING FROM EXCESSIVE AND HEAVY RAINFALL
ALONG/EAST US-281 THROUGH THURSDAY.
- TEMPERATURES WARM FROM SLIGHTLY BELOW AVERAGE TODAY TO NEAR
AVERAGE BY TOMORROW, WHILE MOSTLY MINOR RISKS OF HEAT-RELATED
ILLNESSES (LEVEL 1/4) PERSIST.
DISCUSSION
ISSUED AT 301 PM CDT MON OCT 5 2026
WELL-ABOVE AVERAGE MOISTURE CONTENT FROM A DEPARTING FRONTAL
BOUNDARY AND MODEST UPPER LEVEL DIVERGENCE FROM A DEEPENING TROUGH
OVER THE SOUTHWESTERN GULF MAINTAIN MEDIUM TO LIKELY (40-90%)
CHANCES OF RAIN THROUGH WEDNESDAY, REMAINING MOSTLY ALONG/EAST
I-69 E. TOWARDS THE MIDDLE TO LATER PART OF THE WEEK, SLIGHTLY
BETTER FORCING AND A BIT OF VORTICITY ADVECTION FROM A SHORTWAVE
PASSING OVER TEXAS COULD BRING A REGION-WIDE MEDIUM TO LIKELY
(40-70%) CHANCE OF RAIN ON THURSDAY AND A LOW TO MEDIUM (20-40%)
ON FRIDAY. FOLLOWING, LOW (15-30%) CHANCES OF RAIN STILL REMAIN
POSSIBLE ALONG/EAST US-281.
IN ASSOCIATION WITH THE DEEPENING TROUGH OVER THE GULF, NHC
INDICATES A MEDIUM (40%) OF TROPICAL DEVELOPMENT OF A LOW PRESSURE
SYSTEM, CURRENTLY SITUATED OVER THE SOUTHWESTERN GULF, THROUGH THE
NEXT 48 HOURS AND A HIGH (80%) CHANCE OF TROPICAL DEVELOPMENT
THROUGH THE 7 DAY FORECAST. ALTHOUGH THE GREATEST CONCERN FROM THIS
SYSTEM IS LIKELY TO REMAIN AN ONGOING COASTAL FLOODING AND RIP
CURRENT THREAT, ASSOCIATED SURFACE TROUGHING COULD WORK WITH DAYTIME
INSTABILITY AND WELL-ABOVE AVERAGE MOISTURE CONTENT TO LEAD TO
ADDITIONAL HEAVY SHOWERS AND A FEW THUNDERSTORMS THROUGH THURSDAY,
DISCUSSED FURTHER BELOW.
AT THIS TIME, THERE IS THE POSSIBILITY OF TOTAL ADDITIONAL
RAINFALL AMOUNTS BY FRIDAY MORNING RANGING AROUND 1.0-4.5 INCHES,
OR MORE, ALONG/EAST I-69 E, HIGHEST OVER THE GULF COAST; LREF
PROBABILISTIC DATA SUGGESTS A 30-60% PROBABILITY OF TOTALS
EXCEEDING 3 INCHES ACROSS THE EASTERN PORTIONS OF THE LOWER RGV,
HIGHEST ALONG THE COAST, WHERE THERE IS A 30-40% PROBABILITY OF
EXCEEDING 4 INCHES. DUE TO THIS RISK, WPC GRADUALLY EXPANDS A
MARGINAL RISK OF ISOLATED FLASH FLOODING FROM SOUTHEAST CAMERON
TODAY/TONIGHT TO ALL OF THE LOWER RGV TO AS FAR NORTH AS SOUTHERN
KENEDY AND AS FAR WEST AS SOUTHEASTERN HIDALGO COUNTY ON
WEDNESDAY, SLIDING EASTWARD TO THE EASTERNMOST COUNTIES ON
THURSDAY. HOWEVER, IT SHOULD BE NOTED THAT THERE REMAINS A GREAT
DEAL OF UNCERTAINTY WITH THIS FORECAST, ESPECIALLY WITH HOW THE
SHORTWAVE PASSING OVER THE SOUTHERN PLAINS INTERACTS WITH THE
POTENTIAL DEVELOPING TROPICAL SYSTEM, SO THE FLOODING RISK AND
EXPECTED RAINFALL AMOUNTS ARE HIGHLY SUBJECT TO CHANGE.
OTHERWISE, PARTIAL CLOUD CLEARING IS EXPECTED TO WARM HIGH
TEMPERATURES FROM THE LOW/MID 80S TODAY TO THE UPPER 80S/LOW 90S
BY TOMORROW. RETURN FLOW AND INCREASING MOISTURE CONTENT OVER THE
WEEKEND COULD WARM TEMPERATURES FURTHER TO THE LOW/MID 90S WHILE
ALSO EXPANDING MODERATE RISKS OF HEAT-RELATED ILLNESSES FROM THE
POPULATED REGIONS OF THE RGV TO MORE OF DEEP SOUTH TEXAS BY THE
BEGINNING OF NEXT WEEK. MINOR HEAT RISKS ARE EXPECTED FOR MOST OF
THE CWA IN THE MEANTIME.
AVIATION
(18Z TAFS)
ISSUED AT 1214 PM CDT MON OCT 5 2026
OVERCAST MVFR SKIES ARE LIKELY TO CONTINUE THROUGH THE 18Z TAF
CYCLE, ESPECIALLY AT KHRL AND KBRO, THOUGH SOME DRIER AIR ARRIVING
FURTHER WEST TONIGHT MAY ALLOW FOR CEILINGS TO RISE TO VFR OVER
KMFE THIS EVENING AND POSSIBLY SCATTERED OVERNIGHT. YET, IN THE
MEANTIME, INTERMITTENT LIGHT TO MODERATE SHOWER ACTIVITY COULD
RESULT IN BRIEF PERIODS OF IFR CEILINGS AT ALL TAF SITES. MODERATE
NORTHERLY WINDS (10-15+ KNOTS, GUSTING TO 20-25 KNOTS) BECOME
LIGHT TO GENTLE OVERNIGHT. DRIER CONDITIONS ARE ANTICIPATED BY
TOMORROW MORNING AS NORTHWESTERLY WINDS FURTHER EAST (KHRL AND
KBRO) PICK BACK UP TO SIMILAR SPEEDS AS TODAY, THOUGH REMAINING
LIGHT AT KMFE.
MARINE
ISSUED AT 301 PM CDT MON OCT 5 2026
SEAS ARE EXPECTED TO CONTINUE IMPROVING THROUGHOUT THE REMAINDER OF
THIS EVENING AND OVERNIGHT AS NORTHERLY TO NORTHEASTERLY WINDS
GRADUALLY WEAKEN TO MODERATE TO FRESH, WITH MODERATE (3-5 FT) SEAS
PREVAILING THROUGH THE MIDDLE OF THE WEEK. THE REST OF THE FORECAST
IS SUBJECT TO CHANGE AND WILL LARGELY BE DEPENDENT ON THE
STRENGTHENING OF A LOW PRESSURE SYSTEM OVER THE SOUTHWESTERN
GULF, WHICH NHC HAS A MEDIUM (40%) OF TROPICAL DEVELOPMENT THROUGH
THE NEXT 48 HOURS AND A HIGH (80%) CHANCE OF TROPICAL DEVELOPMENT
THROUGH THE 7 DAY FORECAST. FOR THE TIME BEING, MEDIUM TO LIKELY
(50- 90%) CHANCES OF RAIN GRADUALLY DROP THROUGHOUT THE WEEKEND TO
A LOW TO MEDIUM (20-40%) CHANCE.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 75 87 76 89 / 80 80 50 70
HARLINGEN 71 89 72 92 / 70 60 30 60
MCALLEN 74 92 75 94 / 20 20 10 40
RIO GRANDE CITY 72 92 72 93 / 10 0 0 10
SOUTH PADRE ISLAND 79 85 80 86 / 90 80 70 80
BAYVIEW/PORT ISABEL 75 87 76 89 / 90 80 60 70
BRO WATCHES/WARNINGS/ADVISORIES
TX...HIGH RIP CURRENT RISK UNTIL 7 PM CDT THIS EVENING FOR TXZ451-454-
455.
GM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR GMZ135-155-
175.
SHORT TERM...65-IRISH
LONG TERM....65-IRISH
AVIATION...65-IRISH
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