705
FXUS64 KBRO 231101 AAA
AFDBRO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
601 AM CDT THU JUL 23 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 559 AM CDT THU JUL 23 2026
- DAILY ABOVE AVERAGE TEMPERATURES PERSIST, MAXIMIZING AROUND 100
TO 107+ F, WITH HEAT INDICES OF 105 TO 111+ F, CONTINUING
MODERATE TO MAJOR HEAT RISKS (LEVELS 2/4 AND 3/4), POSSIBLY
BECOMING MOSTLY MAJOR WITH POCKETS OF EXTREME HEAT RISKS (LEVEL
4/4) BY THE MIDDLE OF NEXT WEEK.
- A HEAT ADVISORY IS IN EFFECT FOR ZAPATA AND STARR COUNTIES
FROM 1 PM TO 7 PM THURSDAY FOR HEAT INDICES OF 111 TO 113 F AND
A SPS IS IN EFFECT FOR JIM HOGG, BROOKS AND INLAND KENEDY
COUNTIES FOR HEAT INDICES OF 108 TO 111 F, GENERALLY WITHIN THE
HOURS OF 12 PM TO 7 PM.
- THE WEATHER PREDICTION CENTER (WPC) HIGHLIGHTS MOST OF DEEP
SOUTH TEXAS WITHIN A MARGINAL (LEVEL 1 OF 4) RISK OF POSSIBLE
(AT LEAST 5% CHANCE) ISOLATED FLASH FLOODING FROM EXCESSIVE AND
HEAVY RAINFALL TO AS FAR SOUTH AS NORTHERN/NORTHWESTERN
CAMERON AND SOUTHEASTERN HIDALGO COUNTIES FOR THURSDAY THROUGH
THURSDAY NIGHT.
- CHANCES OF RAIN INCREASE THROUGHOUT THURSDAY TO AS MUCH AS A
MEDIUM TO LIKELY (50-80%) CHANCE BY THURSDAY EVENING/NIGHT AND
TOTAL RAINFALL AMOUNTS OF 1.0-2.0+ INCHES ARE POSSIBLE ACROSS
THE NORTHERN RANCHLANDS AND RIO GRAND PLAINS.
- A LOW RISK OF LIFE-THREATENING RIP CURRENTS CONTINUES THROUGH
THURSDAY AFTERNOON, BUT STAY TUNED FOR UPDATES ON THE POTENTIAL
FOR INCREASED RISKS OF RIP CURRENTS, ELEVATED SURF AND MINOR
COASTAL FLOODING POSSIBLE LATER THIS WEEK IN ASSOCIATION WITH
TROPICAL STORM BERTHA.
DISCUSSION
ISSUED AT 1039 PM CDT WED JUL 22 2026
WE WILL START OFF THE DISCUSSION WITH THE MOST IMMEDIATE FOCUS OF
THE FORECAST, WHICH IS THE ANTICIPATED RAINFALL ASSOCIATED WITH
TROPICAL STORM BERTHA, PROJECTED TO REMAIN MORE OR LESS ON A
WESTWARD TRACK, BRINGING THE MAIN AND MOST DIRECT IMPACTS TO
COASTAL/SOUTHERN LOUISIANA AND THE UPPER TEXAS COAST/SOUTHEASTERN
TEXAS THROUGH THE END OF THE WORK-WEEK. MEANWHILE, NORTHEASTERLY
UPPER LEVEL WINDS CIRCULATING THE SOUTHEASTERN SIDE OF A 549-497+
DAM HIGH PRESSURE ALOFT IS ANTICIPATED TO ADVECT ASSOCIATED DEEP,
TROPICAL MOISTURE AND CONVECTION SOUTHWESTWARD TO SOUTHERN AND DEEP
SOUTH TEXAS THROUGH THE NEXT 24-48 HOURS. AHEAD OF THE UNSETTLED
WEATHER, WE ANTICIPATE STRONG SUBSIDENCE ALOFT TO RESULT IN ANOTHER
DAY OF NEARLY WIDESPREAD LOW/MID 100S ALONG/WEST OF I-69 E WITH
UPPER 100S (107+ F) OVER THE RIO GRANDE PLAINS ALONG WITH A MOSTLY
MAJOR HEAT RISK AS DEWPOINTS RISE. A HEAT ADVISORY IS IN EFFECT FOR
ZAPATA AND STARR COUNTIES FROM 1 PM TO 7 PM THURSDAY FOR HEAT
INDICES OF 111 TO 113 F AND A SPS IS IN EFFECT FOR JIM HOGG, BROOKS
AND INLAND KENEDY COUNTIES FOR HEAT INDICES OF 108 TO 111 F,
GENERALLY WITHIN THE HOURS OF 12 PM TO 7 PM. DEPENDING ON WHEN
CLOUDS INCREASE, TEMPERATURES COULD FALL BENEATH ADVISORY AND
STATEMENT CRITERIA BEFORE 7 PM.
AT THIS TIME, THERE STILL REMAINS CONSIDERABLE AMOUNT OF UNCERTAINTY
ON THE TIMING AND SOUTHWARD EXTENT OF THE MOISTURE FIELD, THE LEVEL
TO WHICH MOISTURE CONTENT INCREASES AND THE RESULTING COVERAGE,
RAINFALL RATES AND TOTAL RAINFALL AMOUNTS OF THE ARRIVING
CONVECTION. AT THIS TIME, WE GENERALLY EXPECT FOR LOW TO MEDIUM
(20-40%) CHANCES OF RAIN DURING THE MORNING AND AFTERNOON TO
SPREAD WESTWARD FROM THE COAST AND INCREASE TO AS MUCH AS A MEDIUM
TO LIKELY (50-80%) CHANCE ALONG/WEST OF US-281 THURSDAY EVENING
INTO LATE THURSDAY NIGHT. MEANWHILE, CHANCES OF OF RAIN BEGIN
DIMINISHING FROM WEST TO EAST, BEGINNING AT THE COAST BY LATE
THURSDAY NIGHT BEFORE ALL RAIN EXITS THE CWA BY POSSIBLY FRIDAY
MORNING. IN GENERAL, THE HIGHEST CHANCES OF RAIN AND RAINFALL
AMOUNTS ARE LIKELY TO BE ACROSS THE RIO GRANDE PLAINS AND THE
NORTHERN RANCHLANDS ALONG/WEST OF US-281, WHERE 1.0 TO 2.0+
INCHES OF RAIN ARE POSSIBLE. THE LATEST PROBABILISTIC NBM GUIDANCE
SUPPORTS AROUND A 30-40% CHANCE OF RAINFALL AMOUNTS EXCEEDING 2.0
INCHES. DUE TO THE POTENTIAL, THOUGH LOW CONFIDENCE, FOR VERY
HIGH MOISTURE CONTENT (PWATS EXCEEDING 2.6+ IN.), MORE WIDESPREAD
HEAVY RAIN AND/OR A SOUTHWARD SHIFT, WPC HIGHLIGHTS MOST OF THE
REGION (AS FAR SOUTH AS NORTHERN/NORTHWESTERN CAMERON COUNTY AND
SOUTHEASTERN HIDALGO COUNTY) WITHIN A MARGINAL RISK (AT LEAST 5%
CHANCE) OF POSSIBLE ISOLATED FLASH FLOODING FROM EXCESSIVE AND
HEAVY RAINFALL THURSDAY THROUGH THURSDAY NIGHT.
ADDITIONALLY, ALTHOUGH SPC INDICATES A GENERAL CHANCE OF SUB-SEVERE
THUNDERSTORMS, A DECENT AMOUNT OF INSTABILITY (CAPE NEAR 1,000 J/KG
OR MORE) AND POSSIBLY 25-30+ KNOT SHEAR COULD BE ENOUGH TO GENERATE
A FEW STRONG THUNDERSTORMS CAPABLE OF PRODUCING HEAVY RAIN AND WIND
GUSTS UP TO 40 MPH. CHANCES OF SEVERE THUNDERSTORMS ARE LOW BUT NOT
COMPLETELY OUT OF THE QUESTION.
OTHERWISE, HIGH PRESSURE ALOFT, BRIEFLY MENTIONED ABOVE, RETREATS TO
AND BUILDS OVER THE DESERT SOUTHWEST THROUGH THIS WEEKEND, POSSIBLY
PEAKING AS MUCH AS 600 DAM ON SATURDAY BEFORE GRADUALLY SHIFTING
BACK TO THE SOUTHERN PLAINS BY THE EARLY TO MIDDLE PARTS OF NEXT
WEEK, GENERALLY MAINTAINING 594-497 DAM. A MORE DISTANT HIGH OVER
THE WEEKEND SHOULD HELP SLIGHTLY COOL HIGH TEMPERATURES BY A FEW
DEGREES, BUT THEN WIDESPREAD INLAND HIGHS IN THE LOW/MID 100S
RETURN BY MONDAY AS THE HIGH PRESSURE ADVANCES EASTWARD AGAIN.
MOSTLY MODERATE HEAT RISKS, WITH POCKETS OF MAJOR ALONG/EAST I-69
E, ARE ANTICIPATED FRIDAY THROUGH SUNDAY, BUT MAJOR HEAT RISKS
BEGIN TO EXPAND NEXT MONDAY, BECOMING MOSTLY MAJOR WITH POCKETS OF
EXTREME HEAT RISKS BY THE MIDDLE OF NEXT WEEK AS PULSES OF
MOISTURE COINCIDE WITH INCREASING SUBSIDENCE ALOFT. ADDITIONAL
SPSS ARE LIKELY AS DAILY AFTERNOON HEAT INDICES PEAK AROUND 105 TO
111+ F, ESPECIALLY ACROSS THE INLAND AND COASTAL PORTIONS OF
CAMERON, WILLACY AND KENEDY COUNTIES. HEAT ADVISORIES ARE ALSO
POSSIBLE BY EARLY NEXT WEEK.
A LOW RISK OF LIFE-THREATENING RIP CURRENTS CONTINUES THROUGH
THURSDAY AFTERNOON. AS THE WEEK PROGRESSES, POTENTIAL LONG PERIOD
SWELL AND PERHAPS ELEVATED SURF, GENERATED BY TROPICAL STORM BERTHA,
COULD ARRIVE TO THE LOWER TEXAS COASTAL WATERS LATER IN THE WEEK;
ELEVATED RISKS OF LIFE-THREATENING RIP CURRENTS, HIGHER SURF AND
MINOR COASTAL FLOODING ARE POSSIBLE AND MAY LEAD TO MORE DANGEROUS
BEACH AND SWIMMING CONDITIONS.
AVIATION
(12Z TAFS)
ISSUED AT 559 AM CDT THU JUL 23 2026
MORE ACTIVE WEATHER WILL OCCUR TODAY. THE APPROACH OF LOW PRESSURE
IN THE MIDDLE LAYERS OF THE ATMOSPHERE FROM THE NORTHEAST WILL
PRODUCE CONVECTION, AND THIS CONTINUES TO BE REFLECTED IN THE MOST
RECENT TAF ISSUANCE WITH A TEMPO FOR EACH OF THE AERODROMES, WITH
TIMING BASED ON THE HRRR MODEL. OVERALL, VFR WILL PREVAIL THROUGH
THE NEXT 24 HOURS.
MARINE
ISSUED AT 1039 PM CDT WED JUL 22 2026
GENTLE TO MODERATE SOUTHEASTERLY WINDS, OCCASIONALLY FRESH, WITH
SLIGHT TO MODERATE (2-4 FT) SEAS ARE EXPECTED TO ENHANCE TO MOSTLY
MODERATE TO FRESH, STRONG AT TIMES, WITH MODERATE (3-5 FT) SEAS BY
LATE THURSDAY AFTERNOON, CONTINUING THROUGH FRIDAY NIGHT, DURING
WHICH TIME SMALL CRAFT EXERCISE CAUTION CONDITIONS ARE LIKELY.
ALTHOUGH THE MOST DIRECT IMPACTS FROM TROPICAL STORM BERTHA, MOVING
WEST OVER THE NORTHERN GULF, ARE CURRENTLY ANTICIPATED TO REMAIN
WELL TO THE NORTH, SLIGHTLY ELEVATED SEAS FROM ASSOCIATED SWELL
COULD ARRIVE TO THE LOWER TEXAS COASTAL WATERS LATER THIS WEEK
AND/OR THIS WEEKEND. OTHERWISE, GENTLE TO MODERATE SOUTHEASTERLY
WINDS AND SLIGHT TO MODERATE (2-5 FT) SEAS RESUME ON SATURDAY.
CHANCES OF RAIN INCREASE TONIGHT TO AS MUCH AS A MEDIUM TO LIKELY
(50-80%) CHANCE BY THURSDAY MORNING, WANE A BIT INTO THE LATE
AFTERNOON HOURS BEFORE INCREASING BACK TO A MEDIUM TO LIKELY (40-
70%) CHANCE BY THE EVENING HOURS. CHANCES GRADUALLY DIMINISH FROM
EAST TO WEST TO 10% OR LESS BY LATE THURSDAY NIGHT.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 96 81 96 80 / 30 20 0 0
HARLINGEN 99 78 98 77 / 40 40 0 0
MCALLEN 104 81 101 79 / 20 60 10 0
RIO GRANDE CITY 105 79 101 77 / 30 70 10 0
SOUTH PADRE ISLAND 88 81 88 81 / 40 20 0 0
BAYVIEW/PORT ISABEL 95 79 94 79 / 40 30 0 0
BRO WATCHES/WARNINGS/ADVISORIES
TX...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS EVENING
FOR TXZ248-252.
GM...NONE.
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