054
FXUS64 KBRO 270551 AAA
AFDBRO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1251 AM CDT THU MAR 27 2025
..NEW AVIATION
SHORT TERM
(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 253 PM CDT WED MAR 26 2025
KEY MESSAGES:
* ENVIRONMENTAL CONDITIONS ARE BECOMING MORE FAVORABLE FOR STRONG TO
SEVERE CONVECTION THROUGH THE SHORT TERM.
* A FLASH FLOOD WATCH HAS BEEN ISSUED FOR TONIGHT THROUGH FRIDAY
MORNING.
JUST THE HIGHLIGHTS THIS DISCUSSION. A MARGINAL SPC RISK WILL BECOME
SLIGHT ON THURSDAY. SPC GIVES DETAILS BELOW.
EXTENSIVE DEEP CONVECTION WILL LIKELY BE ONGOING ACROSS PARTS OF
SOUTH TEXAS THURSDAY MORNING, IN ASSOCIATION WITH A LEADING LOW-
AMPLITUDE SHORTWAVE IMPULSE. HOW FAR SOUTH-SOUTHEAST ATTENDANT COLD
POOL/LARGE-SCALE OUTFLOW IS UNCERTAIN, WITH THE 12Z NAM DISPLACED
FARTHER NORTHWEST THAN THE BULK OF PREFERRED GUIDANCE. THIS WILL
HAVE PROFOUND IMPACTS ON SPATIAL EXTENT AND AMPLITUDE OF D2 SEVERE
POTENTIAL. PRIOR OVERTURNING/STABILIZATION IS LIKELY TO BE MUCH MORE
PROMINENT THAN INDICATED BY THE 12Z NAM.
SOME SEVERE WIND/EMBEDDED HAIL THREAT MAY ACCOMPANY THE LEADING
CONVECTION ACROSS DEEP SOUTH TEXAS AND THE LOWER TEXAS COAST, BEFORE
IT SHIFTS OFFSHORE/WEAKENS THROUGH LATE MORNING INTO MIDDAY.
TRAILING OUTFLOW WILL SERVE AS A FOCUS FOR RENEWED DEVELOPMENT
BEYOND THE HIGHER TERRAIN OF NORTHEAST MEXICO. CONFIDENCE IS LOW IN
ACHIEVING SUBSTANTIAL RETREAT/DESTABILIZATION NORTH OF THE OUTFLOW.
BUT WITH PERSISTENCE OF WEAK MID-LEVEL TROUGHING UPSTREAM AND
MODERATE MID-LEVEL SOUTHWESTERLIES, RENEWED SEVERE POTENTIAL MAY
OCCUR ACROSS PARTS OF SOUTH TEXAS THURSDAY EVENING/NIGHT WITH SLOW-
MOVING CLUSTERS. EMBEDDED SUPERCELLS COULD POSE A MIXED SEVERE
HAIL/WIND THREAT.
ON THE PRECIP SIDE, WE EXPECT DEVELOPING AND EXPANDING CLUSTERS OF
HEAVY SHOWERS AND THUNDERSTORMS THROUGH THIS AFTERNOON. DRY
ANTECEDENT SOILS, SLOW CELL MOTION AND HEAVY RAIN WILL SUPPORT A
HIGHER FLASH FLOOD THREAT. SYNOPTIC SCALE FACTORS WILL AGAIN SUPPORT
HEAVY RAINFALL ON THURSDAY, BUT MESOSCALE FACTORS WILL INFLUENCE THE
EXACT TIMING AND LOCATION OF SPECIFIC HEAVY RAIN OPPORTUNITIES. A
SLIGHT TO MODERATE ERO AREA (ABOVE FLASH FLOOD GUIDANCE) WILL SHIFT
EAST AND SOUTH ON THURSDAY
LONG TERM
(FRIDAY THROUGH NEXT WEDNESDAY)
ISSUED AT 253 PM CDT WED MAR 26 2025
KEY MESSAGES:
-RAIN COMES TO AN END ON FRIDAY
-WARMER THAN AVERAGE TEMPERATURES RETURN BY SATURDAY
AT THE MID-TO-UPPER LEVELS, THE LONG TERM BEGINS FRIDAY MORNING WITH
THE BASE OF THE TROUGH PASSING OVER DEEP SOUTH TEXAS AND THE RIO
GRANDE VALLEY, EXITING THE COUNTY WARNING AREA (CWA) BY FRIDAY
EVENING. FOLLOWING, A WEAK MID-UPPER LEVEL RIDGE WILL LEAD TO SLIGHT
WEST-NORTHWESTERLY FLOW ALOFT FRIDAY NIGHT INTO SATURDAY. ZONAL FLOW
RETURNS SATURDAY NIGHT INTO SUNDAY BEFORE GRADUALLY GIVING WAY TO A
NORTHWESTERLY FLOW FROM THE LATER PART OF SUNDAY AND INTO THE FIRST
HALF NEXT WEEK AS A SUBTROPICAL RIDGE BUILDS OFF THE NORTHWESTERN
COAST OF MEXICO, MOVING EASTWARD. AS THE EXPANDING RIDGE DIGS ON THE
BACKSIDE OF A SHORTWAVE TROUGH MOVING EASTWARD AND OVER NORTH TEXAS
SUNDAY NIGHT, A COLD FRONT WILL PASS THROUGH TEXAS, ARRIVING AS A
WEAKENING FRONTAL BOUNDARY MONDAY AFTERNOON, LINGERING INTO TUESDAY.
AT THE SURFACE, WET CONDITIONS ARE EXPECTED FRIDAY MORNING WITH A
MEDIUM TO HIGH (30-60%) CHANCE OF SHOWERS AND THUNDERSTORMS, WITH
LOWER CHANCES TO THE WEST AND HIGHER CHANCES TO THE EAST. THE
HIGHEST CHANCES (60-70%) OF CONVECTION EXIST ACROSS BROOKS AND
KENEDY COUNTIES. AS THE TROUGH, DISCUSSED ABOVE, PULLS AWAY FRIDAY
AFTERNOON AND EVENING, CHANCES OF SHOWERS DECREASE TO 15-40%, WITH
THE LOWEST CHANCES ACROSS THE WESTERN NORTHERN RANCHLANDS AND UPPER
RGV, WITH LESS THAN 15% FURTHER WEST, AND THE BEST PROBABILITIES
CLOSER TO THE COAST AND THE BARRIER ISLANDS. ACROSS THE CWA, AN
ADDITIONAL 0.05-0.35 INCH OF RAIN IS POSSIBLE ON FRIDAY BEFORE
COMING TO AN END. ALTHOUGH HEAVIER SHOWERS COULD RESULT IN LOCALIZED
HIGHER AMOUNTS ACROSS BROOKS AND KENEDY COUNTIES, AS WELL AS THE
COASTAL COUNTIES, THE LREF AND NBM PROBABILITIES ONLY YIELD A 10-15%
CHANCE OF AMOUNTS EXCEEDING MORE THAN 0.75 INCHES. MOSTLY DRY
CONDITIONS RETURN FRIDAY NIGHT AND FOR THE REMAINDER OF THE LONG
TERM.
CLOUD COVER SHOULD KEEP HIGH TEMPERATURES IN THE 80S ON FRIDAY, BUT
UPPER 80S AND LOWER TO MID-90S RETURN TO MUCH OF DEEP SOUTH TEXAS
FROM SATURDAY ONWARD, WITH DAYTIME HIGH TEMPERATURES RUNNING ABOUT 5-
10 DEGREES ABOVE AVERAGE OR WARMER, PARTICULARLY FURTHER WEST AND
INLAND (MIDDLE AND UPPER RGV AND RIO GRANDE PLAINS). OVERNIGHT LOWS
RANGING FROM THE MID TO UPPER 60S FURTHER NORTH, AND LOWER 70S
ACROSS THE RGV, WILL BE THE RECURRING PATTERN THROUGH MONDAY NIGHT.
WINDS TURN EASTERLY ON MONDAY, HOLDING THROUGH TUESDAY AS A WEAK
FRONTAL BOUNDARY LINGERS ACROSS THE REGION. SOUTHEASTERLY FLOW
RETURNS TUESDAY INTO WEDNESDAY, RESULTING IN LOWS MOSTLY IN THE
LOWER 70S TUESDAY AND WEDNESDAY NIGHTS. WEDNESDAY MAY FEATURE THE
WARMEST DAY OF THE LONG TERM WITH HIGHS RANGING FROM NEAR 90 TO
UPPER 90S FURTHER WEST.
AVIATION
(06Z TAFS)
ISSUED AT 1239 AM CDT THU MAR 27 2025
CURRENTLY SEEING MOSTLY MVFR CEILINGS, HOWEVER SOME POCKETS VFR
CEILINGS ARE STILL POSSIBLE FOR THE NEXT SEVERAL HOURS. BEFORE
MORE VFR CEILING SETTLE IN FOR THE OVERNIGHT HOURS AND THE EARLY
MORNING HOURS. HRRR PROJECTS THAT ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS ARE POSSIBLE STARTING LATE IN THE MORNING AND
PERSISTING THROUGH THE REST OF THE AFTERNOON. SOME THUNDERSTORMS
CAN PRODUCT LOCALLY GUSTY WINDS, HAIL, AND REDUCED CEILINGS AND
VISIBILITY TO LIFR CONDITIONS AT TIMES.
MARINE
ISSUED AT 253 PM CDT WED MAR 26 2025
TONIGHT THROUGH THURSDAY NIGHT...A TIGHTER PRESSURE GRADIENT WILL
STRENGTHEN WINDS AND BUILD SEAS THROUGH THURSDAY NIGHT. SMALL CRAFT
MAY NEED TO EXERCISE CAUTION AT TIMES, AND WE MAY NEED A SMALL CRAFT
ADVISORY AT SOME POINT IF WAVE HEIGHTS POKE ABOVE 7 FEET. UNSETTLED
WEATHER WILL GENERATE SCATTERED SHOWERS AND THUNDERSTORMS TONIGHT
THROUGH THURSDAY NIGHT.
FRIDAY THROUGH NEXT WEDNESDAY...SMALL CRAFT EXERCISE CAUTION (SCEC)
HEADLINES, POSSIBLY SMALL CRAFT ADVISORIES, COULD PERSIST THROUGH
FRIDAY NIGHT, PARTICULARLY ACROSS THE OFFSHORE (20-60 NM) GULF
WATERS, AS MODERATE TO FRESH SOUTHEASTERLY WINDS CONTINUE TO
GENERATE MODERATE MODERATE (4-6 FEET, POSSIBLY 7 FEET FOR THE
OFFSHORE WATERS) AS A TIGHTENED PRESSURE GRADIENT CONTINUES
OFFSHORE BEHIND THE DEPARTING TROUGH AND INCOMING HIGH PRESSURE.
THE GRADIENT WEAKENS AND WINDS DIMINISH TO GENTLE TO MODERATE ON
SATURDAY WITH SLIGHT TO MODERATE SEAS CONTINUING FOR MOST OF THE
REST OF THE LONG TERM. WINDS AND SEAS MAY BUILD ONCE AGAIN BY THE
MIDDLE OF NEXT WEEK. CHANCES OF SHOWERS AND THUNDERSTORMS
DIMINISHING SIGNIFICANTLY THROUGHOUT FRIDAY, WITH DRY WEATHER
RETURNING FRIDAY EVENING.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 82 68 80 69 / 40 80 50 0
HARLINGEN 85 66 84 66 / 50 80 50 0
MCALLEN 88 70 88 70 / 60 80 50 0
RIO GRANDE CITY 84 66 86 68 / 70 80 40 0
SOUTH PADRE ISLAND 76 67 75 69 / 40 80 50 0
BAYVIEW/PORT ISABEL 81 66 80 67 / 40 80 50 0
BRO WATCHES/WARNINGS/ADVISORIES
TX...FLOOD WATCH THROUGH FRIDAY MORNING FOR TXZ248>251-351-451.
GM...NONE.
SHORT TERM...54-BHM
LONG TERM....65-IRISH
AVIATION...64-KATZ
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