164
FXUS64 KBRO 070530 AAA
AFDBRO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1230 AM CDT THU MAY 7 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1228 AM CDT THU MAY 7 2026
KEY MESSAGES:
* ALTHOUGH THE RISK IS CONDITIONAL AT THIS POINT, THE STORM
PREDICTION CENTER (SPC) HAS INTRODUCED A MARGINAL RISK (LEVEL
1/5) OF ISOLATED SEVERE THUNDERSTORMS LATE TONIGHT ALONG/WEST
OF US-281, WITH THE PRIMARY THREATS BEING LARGE (1+ INCH HAIL)
AND DAMAGING WINDS (IN EXCESS OF 60 MPH).
* THE WEATHER PREDICTION CENTER (WPC) MAINTAINS A MARGINAL RISK
(LEVEL 1/4) OF ISOLATED FLASH FLOODING ALONG/WEST OF US-281 ON
THURSDAY AND ACROSS THE NORTHERN RANCHLANDS AND NORTHERN HALF
OF ZAPATA COUNTY ON FRIDAY.
* A MEDIUM RISK OF RIP CURRENTS CONTINUES THROUGH THURSDAY
AFTERNOON.
* MINOR TO MODERATE HEAT RISKS (LEVELS 1/4 AND 2/4) CONTINUE
THURSDAY THROUGH SUNDAY AS AFTERNOON HEAT INDICES RANGE FROM
95-105 F, FOLLOWED BY A MINOR HEAT RISK MONDAY THROUGH NEXT
WEDNESDAY BEHIND A WEAK COLD FRONT SUNDAY NIGHT.
DISCUSSION
ISSUED AT 1037 PM CDT WED MAY 6 2026
AT THE TIME OF THIS WRITING, 7:18 PM, A VERY UNSTABLE AND WARM
AIRMASS CONTINUES OVER DEEP SOUTH TEXAS, WITH SURFACE BASED CAPE
VALUES RANGING FROM NEAR 4,000-5,000+ J/KG AND A CAP BEGINNING TO
FORM ACROSS THE LOWER TEXAS COASTAL COUNTIES, THE RGV AND THE RIO
GRANDE PLAINS. A SURFACE HIGH PRESSURE BUILDING OVER THE CENTRAL AND
SOUTHERN PLAINS IN WAKE OF A DEPARTING MID/UPPER LEVEL TROUGH HAS
ALREADY PUSHED A COLD FRONT SOUTHWARD THROUGH SAN ANTONIO AND IS
EXPECTED TO BEGIN MOVING INTO OUR REGION LATE TONIGHT INTO THURSDAY
MORNING. THE LATEST RUNS OF THE RAP AND THE HRRR, WHICH ARE
CAPTURING A RELATIVELY ACCURATE DEPICTION OF THE ATMOSPHERE ACROSS
THE REGION AND UPSTREAM, ARE INDICATING THAT FRONTAL LIFT AND
FORCING ALOFT WILL AID IN THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS OVER THE SIERRA MADRE AS THE FRONT ARRIVES TO THE
NORTHERN RANCHLANDS. IN THE MEANTIME, A CAPPING INVERSION IS
ANTICIPATED TO SPREAD ACROSS THE CWA ALONG WITH A WEAKENING
STEERING 700 MB FLOW, THUS LIKELY KEEPING THE STRONGEST CONVECTION
WEST AND SOUTHWEST OF THE US-MEXICO BORDER AS STORMS SLOW FORWARD
MOVEMENT AND WEAKEN WHEN ARRIVING TO THE CAP, LEAVING THE
POSSIBILITY OF SHOWERS AND SUB-SEVERE THUNDERSTORMS ACROSS MAINLY
THE UPPER RGV, RIO GRANDE PLAINS AND THE NORTHERN RANCHLANDS.
HOWEVER, SHOULD SHEAR AND WINDS ALOFT REMAIN ELEVATED AND THE
FRONT MOVE FASTER, MUCAPE VALUES OF AROUND 2,000-3,500+ J/KG, MID-
LEVEL LAPSE RATES NEARING 7-8+ C/KM AND 2,000-3000+ J/KG SURFACE-
BASED CAPE COULD LEAD TO ISOLATED STRONG TO SEVERE THUNDERSTORMS
ALONG/WEST OF US-281, WHERE CAPPING COULD BE BREACHED IN A FEW
AREAS. IN THIS CONDITIONAL SCENARIO, ISOLATED LARGE (1"+) HAIL AND
DAMAGING WINDS IN EXCESS OF 60 MPH WOULD BE POSSIBLE. THEREFORE,
SPC HAS INCLUDED ALL OF ZAPATA, JIM HOGG, BROOKS AND THE
NORTHWESTERN HALF OF BROOKS COUNTIES WITHIN A MARGINAL RISK OF
ISOLATED THUNDERSTORMS.
WHETHER OR NOT THIS EVENT MATERIALIZES COULD FURTHER PLAY A ROLE ON
SHOWERS AND POTENTIAL THUNDERSTORM DEVELOPMENT DURING THE DAY
THURSDAY AND/OR THURSDAY NIGHT AS EMBEDDED DISTURBANCES WITHIN
SOUTHWESTERLY FLOW ALOFT AHEAD OF AN UPPER LEVEL LOW COULD LEAD TO
UPPER LEVEL DIVERGENCE AND ADDITIONAL CONVECTION. CURRENTLY, WE
ANTICIPATE CHANCES OF RAIN TO GRADUALLY INCREASE FROM A LOW TO
MEDIUM (20-50%) CHANCE OF RAIN ON THURSDAY AND THURSDAY NIGHT TO
AS MUCH AS A MEDIUM TO LIKELY (40-70%) CHANCE FRIDAY NIGHT, WHEN A
700 MB TROUGH MOVES THROUGH. ALTHOUGH MID-LEVEL MOISTURE MAY BE
BORDERLINE TOO DRY, LOWER LEVEL RELATIVE HUMIDITY OF 80-90%+ IS
LIKELY DURING THIS TIMEFRAME. THEREFORE, TRAINING OF SHOWERS
COULD LEAD TO A RISK OF ISOLATED FLASH FLOODING, THOUGH MINOR
NUISANCE FLOODING AND HYDROPLANING ARE THE BIGGER CONCERNS,
ESPECIALLY IF HEAVY RAIN DEVELOPS QUICKLY OR RAIN CONTINUES OVER
AREAS FOR A PROLONGED PERIOD OF TIME. AS SUCH, WPC HIGHLIGHTS A
MARGINAL RISK OF ISOLATED FLASH FLOODING FOR MOST AREAS ALONG/WEST
OF US-281 ON THURSDAY AND THE NORTHERN RANCHLANDS AND NORTHERN
ZAPATA COUNTY ON FRIDAY. THE RISK OF ANY ADDITIONAL ROUND OF
ISOLATED TO SEVERE THUNDERSTORMS IS STILL UP IN THE AIR, THOUGH
THE GFS STILL INCONSISTENTLY ADVERTISES A LOW RISK NEAR THE RIO
GRANDE PLAINS AND THE NORTHERN RANCHLANDS THURSDAY NIGHT. EITHER
WAY, BY SATURDAY MORNING, AREAS ALONG/WEST OF I-69 E COULD
RECEIVE 0.3-0.7 OF AN INCH OF RAIN, WITH SOME AREAS IN THE RIO
GRANDE PLAINS RECEIVING UP TO AN INCH OF RAIN. THE LATEST NBM
PROBABILITISTIC GUIDANCE SUGGESTS A 20-30% CHANCE OF THE ENTIRE
REGION RECEIVING AT LEAST 1 INCH OF RAIN AND A 30-40% CHANCE FOR
SOME AREAS ALONG/WEST OF US-281. THIS IS A DOWNWARD TREND IN
COMPARISON TO THIS AFTERNOON. FINALLY, THERE IS A LOW TO MEDIUM
(20-40%) CHANCE OF RAIN ON SATURDAY BEFORE DIMINISHING AS THE
TROUGH PULLS OUT OF THE REGION.
TEMPERATURES IN THE 80S ON THURSDAY RISE TO THE UPPER 80S/LOWER 90S
ON FRIDAY AND SATURDAY, THEN WARMING TO WIDESPREAD 90S ON SUNDAY AS
SOUTHEASTERLY WINDS RETURN. MINOR TO MODERATE HEAT RISKS ARE
ANTICIPATED THROUGH SUNDAY AS AFTERNOON HEAT INDICES GENERALLY RANGE
95-105 F. EMBEDDED MID-LEVEL DISTURBANCES WITHIN RIDGING OVER THE
WESTERN US AND BUILDING SURFACE HIGH OVER THE PLAINS PUSH A WEAK
COLD FRONT INTO DEEP SOUTH TEXAS SUNDAY NIGHT OR MONDAY MORNING,
COOLING TEMPERATURES BACK TO THE 80S/90S INTO THE MIDDLE OF NEXT
WEEK. DRIER AIR BEHIND THE FRONT COULD KEEP A MINOR HEAT RISK
MONDAY INTO NEXT WEDNESDAY.
A MEDIUM RISK OF RIP CURRENTS CONTINUES THROUGH THURSDAY AFTERNOON.
AVIATION
(06Z TAFS)
ISSUED AT 1228 AM CDT THU MAY 7 2026
GENERALLY MVFR CONDITIONS SHOULD PERSIST THROUGH THE PERIOD DUE TO
LOW-LEVEL CLOUDS LINGERING OVER THE REGION. WHILE THERE IS A
CHANCE FOR IFR CONDITIONS DUE TO EVEN LOWER CEILINGS, CONFIDENCE
WAS NOT HIGH ENOUGH TO INCLUDE IN THE TAF PACKAGE. LIKEWISE, SOME
MODELS DID TRY TO BRING SOME SHOWERS AND THUNDERSTORMS INTO THE
AREA AS WELL, BUT CONFIDENCE THERE WAS LOW AS WELL. LIGHT WINDS
ARE EXPECTED FOR THE PERIOD AS WELL.
MARINE
ISSUED AT 1037 PM CDT WED MAY 6 2026
GENTLE SOUTHEASTERLY WINDS AND SLIGHT TO MODERATE (2-4 FT) SEAS
EARLY TONIGHT INCREASE TO MODERATE TO FRESH NORTHEASTERLY WINDS AND
MODERATE (3-5 FT) SEAS, WITH SCEC HEADLINES POSSIBLE, LATE TONIGHT
WITH THE ARRIVAL OF A COLD FRONT, PERSISTING INTO THURSDAY NIGHT.
GENTLE TO MODERATE SOUTHEASTERLY WINDS RESUME ON FRIDAY ALONG WITH
MODERATE (3-5 FT) SEAS. MODERATE NORTHEASTERLY WINDS AND MODERATE
SEAS ARE LIKELY AGAIN BEHIND A WEAK COLD FRONT SUNDAY NIGHT OR
MONDAY MORNING, RETURNING BACK TO GENTLE TO MODERATE SOUTHEASTERLY
WINDS BY THE MIDDLE OF NEXT WEEK. A LOW TO MEDIUM (20-40%) CHANCE
OF RAIN CONTINUES THROUGH SATURDAY.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 86 78 90 78 / 20 20 30 10
HARLINGEN 83 75 91 75 / 20 30 40 10
MCALLEN 84 75 92 76 / 40 50 40 40
RIO GRANDE CITY 85 73 90 75 / 50 60 30 50
SOUTH PADRE ISLAND 80 78 84 79 / 20 20 30 10
BAYVIEW/PORT ISABEL 82 77 89 77 / 20 20 30 10
BRO WATCHES/WARNINGS/ADVISORIES
TX...NONE.
GM...NONE.
SHORT TERM...65
LONG TERM....65
AVIATION...64-KATZ
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