939
FXUS64 KBRO 190353
AFDBRO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1053 PM CDT FRI SEP 18 2026
..NEW DISCUSSION, MARINE
KEY MESSAGES
UPDATED AT 1040 PM CDT FRI SEP 18 2026
- DAILY LOW MEDIUM (20-40% OR HIGHER) CHANCES OF RAIN RETURN NEXT
MONDAY AND BECOME REGION-WIDE BY NEXT TUESDAY.
- TEMPERATURES EASE OFF A FEW DEGREES FROM WIDESPREAD AREAS OF
LOW 100S ALONG/WEST I-69 E TO MOSTLY UPPER 90S BY TUESDAY.
- EXTREME RISKS OF HEAT-RELATED ILLNESSES (LEVEL 4/4) ARE LIKELY
TO CONTINUE FOR PORTIONS OF THE RGV/RIO GRANDE PLAINS WHILE THE
REST OF THE REGION EXPERIENCES MODERATE TO MAJOR RISKS (LEVEL
2/4 AND 3/4).
- A MODERATE RISK OF LIFE-THREATENING RIP CURRENTS CONTINUES
THROUGH SATURDAY AFTERNOON.
DISCUSSION
ISSUED AT 1040 PM CDT FRI SEP 18 2026
A BIT OF A DYNAMIC AND SOMEWHAT UNSETTLED WEATHER PATTERN SETS UP
ACROSS DEEP SOUTH TEXAS THROUGHOUT THE NEXT 7 DAYS OR INTO LATE NEXT
WEEK. SUBSIDENCE AND DRIER AIR ASSOCIATED WITH A 591-594+ DAM HIGH
PRESSURE ALOFT OVER NORTHEAST TEXAS LOWERS MOISTURE CONTENT TONIGHT
THROUGH SUNDAY, CUTTING DOWN ON RAIN CHANCES TO, AT MOST, A LOW
(15%) CHANCE OF AN ISOLATED SHOWER OR TWO OVER THE SOUTHERN
PORTIONS OF THE LOWER AND MID RGV. MEANWHILE, HEIGHTS GRADUALLY
LOWER AS THE HIGH BECOMES WEDGED BETWEEN AN UPPER LEVEL LOW
REGRESSING TO THE EASTERN GULF AND AS ANOTHER PUSHES EAST FROM
THE INTERMOUNTAIN WEST TO THE PLAINS BY MONDAY. FOLLOWING, THE
COMBINATION OF ENHANCED LIFT OVER THE GULF RESULTING FROM A SERIES
OF HIGH PRESSURE SURGES AND A BIT OF NEARBY MID/UPPER LEVEL
TROUGH VORTICITY ADVECTION ALONG THE SOUTHEASTERN PERIPHERY OF A
HIGH PRESSURE ALOFT EMERGING OVER THE SOUTHERN PLAINS RE-ENHANCES
MOISTURE CONTENT AND CHANCES OF RAIN. AS A RESULT, DAILY LOW TO
MEDIUM (20-40% OR HIGHER) CHANCES OF RAIN ALONG THE DAYTIME
SEABREEZE BOUNDARY EXPAND FROM ALONG/EAST US-281 NEXT MONDAY TO
MOST OF THE REGION BY NEXT TUESDAY. HEAVY RAIN AND NUISANCE
FLOODING ARE POSSIBLE AS PWAT VALUES INCREASE, ESPECIALLY TOWARD
THE MIDDLE AND LATER PARTS OF THE WEEK. STILL SHOULD NOTE THAT
THIS IS SUBJECT TO CHANGE AND WILL DEPEND ON THE POSITIONING AND
STRENGTH OF THE HIGH PRESSURE ALOFT.
WIDESPREAD LOWER 100S ACROSS THE NORTHERN RANCHLANDS ALONG/WEST OF I-
69 E AND ACROSS THE RGV/RIO GRANDE PLAINS ALONG/WEST US-281 ARE
EXPECTED SATURDAY THROUGH MONDAY, SLIGHTLY COOLING OFF TO MOSTLY THE
UPPER 90S BY TUESDAY AS CLOUDS BUILD. ADDITIONALLY, AREAS OF EXTREME
HEAT-RELATED ILLNESSES ACROSS PORTIONS OF THE RGV/RIO GRANDE PLAINS
CONTINUE THROUGH MONDAY AND THEN BECOME MORE LIMITED TO THE LOWER
RGV BY TUESDAY WHILE THE REST OF THE REGION EXPERIENCES MODERATE TO
MAJOR RISKS. SPSS FOR HEAT INDICES OF 108-111 F ARE POSSIBLE AS
WELL.
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 1040 PM CDT FRI SEP 18 2026
LIGHT TO GENTLE, OCCASIONALLY MODERATE, EASTERLY TO SOUTHEASTERLY
WINDS BECOME GENTLE TO MODERATE NORTHEASTERLY TO EASTERLY ON TUESDAY
AND MOSTLY MODERATE BY LATE WEEK. SLIGHT TO MODERATE (2-4 FT) SEAS
EASE TO SLIGHT (1-2 FT) SEAS ON SUNDAY BEFORE INCREASING BACK TO
MODERATE LATER IN THE WEEK. LOW (15-30%) CHANCES OF RAIN TONIGHT
DECREASE TO 10% OR LESS BY SATURDAY AFTERNOON. LOW CHANCES RETURN ON
SUNDAY, INCREASING TO LOW TO MEDIUM BY TUESDAY.
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...65-IRISH
LONG TERM....65-IRISH
AVIATION...65-IRISH
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