814
FXUS64 KBRO 210547 AAA
AFDBRO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1247 AM CDT SUN JUN 21 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1241 AM CDT SUN JUN 21 2026
- ADDITIONAL HEAVY RAIN IS POSSIBLE DURING THE EARLY TO LATE
NIGHT HOURS TONIGHT AND WPC KEEPS NEARLY ALL OF DEEP SOUTH
TEXAS WITHIN A SLIGHT RISK (LEVEL 2 OF 4) OF POSSIBLE SCATTERED
FLASH FLOODING FROM EXCESSIVE AND HEAVY RAINFALL UNTIL SUNDAY
MORNING.
- DRY CONDITIONS RESUME SUNDAY AND ELEVATED MOISTURE CONTENT
LEADS TO MODERATE TO MAJOR HEAT RISKS (LEVELS 2 AND 3 OF 4)
THROUGH TUESDAY, WITH SPSS POSSIBLE FOR HEAT INDICES OF 108-111
F.
- A MODERATE RISK OF LIFE-THREATENING RIP CURRENTS CONTINUES
THROUGH SUNDAY AFTERNOON, LIKELY TO PERSIST AND/OR ESCALATE TO
A HIGH RISK INTO THE BEGINNING OF THIS UPCOMING WEEK.
DISCUSSION
ISSUED AT 1019 PM CDT SAT JUN 20 2026
THE WEAK MID-LEVEL LOW, WHICH HAS WORKED WITH INSTABILITY AND
IMPRESSIVELY HIGH PWAT VALUES TO RESULT IN NUMEROUS SPSS FOR
STRONG THUNDERSTORMS AS WELL AS SEVERAL FLASH FLOOD WARNINGS AND
FLOOD ADVISORIES OVER DEEP SOUTH TEXAS WITHIN THE PAST 24-36
HOURS, REMAINS IN PLACE OVER SOUTHERN TEXAS AND NORTHEASTERN
MEXICO THROUGH TONIGHT. AT THIS TIME, ALL THAT IS LEFT OF THE
ACTIVE CONVECTION FROM TODAY IS AN AREA OF MOSTLY LIGHT STRATIFORM
RAIN OVER THE SOUTHERN HALF OF HIDALGO COUNTY. ACCORDING TO THE
LATEST SPC MESOANALYSIS AND THE RAP, THERE IS STILL NO CAPPING
INVERSION OVER DEEP SOUTH TEXAS AND THE GFS AND HRRR CONTINUE TO
INDICATE THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS OVER THE
NEXT 6 HOURS OR SO, WITH A LOW TO MEDIUM (20-50%) CHANCE OF RAIN
ALONG/EAST OF US-281 INTO THE PRE-DAWN HOURS. AS PWATS CONTINUE TO
RANGE AROUND 2.0 TO 2.5 TONIGHT, WPC MAINTAINS A SLIGHT RISK OF
POSSIBLE SCATTERED FLASH FLOODING FROM EXCESSIVE AND HEAVY
RAINFALL ACROSS ALL OF DEEP SOUTH TEXAS TONIGHT, WITH THE
EXCEPTION OF THE BARRIER ISLANDS AND EXTREME NORTHWESTERN ZAPATA
COUNTY, WHICH ARE WITHIN A MARGINAL RISK OF POSSIBLE ISOLATED
FLASH FLOODING. BY THE PRE-DAWN TO DAWN HOURS SUNDAY MORNING, MOST
OF THE CONVECTION IS ANTICIPATED TO DIMINISH, REDUCING POPS TO A
LOW (15-30%) CHANCE BY SUNRISE AND DROPPING FURTHER THROUGHOUT
SUNDAY MORNING.
THROUGHOUT THE DAY ON SUNDAY AND INTO SUNDAY NIGHT, HIGH PRESSURE
ALOFT OVER THE BAJA PENINSULA EXPANDS EASTWARD TO THE GULF AND
SHIFTS/WEAKENS THE LOW PRESSURE ALOFT SOUTHWARD, INCREASING
SUBSIDENCE AND CAUSING PWAT VALUES TO PLUMMET TO AS LOW AS AROUND
1.35 IN. BY MONDAY MORNING, WHICH IS MUCH DRIER THAN THE AVERAGE
OF AROUND 1.7-1.8 IN. FOR THIS TIME OF YEAR. MEANWHILE, A SERIES
OF MID-LEVEL SHORTWAVES AND SURFACE LOWS TRAVERSING THE PLAINS
RESULT IN A TIGHTENED PRESSURE GRADIENT, ENHANCING LOWER-LEVEL
MOISTURE FROM ONSHORE SOUTHEASTERLY WINDS GUSTING TO 25-30+ MPH
EACH AFTERNOON THROUGH THE BEGINNING OF THIS UPCOMING WEEK.
THEREFORE, DESPITE SEASONABLY HOT TEMPERATURES, RISING TO THE
MID/UPPER 90S IN THE AFTERNOONS AND MINIMIZING IN THE MID/UPPER
70S TO LOWER 80S OVERNIGHT, HEAT INDICES ARE LIKELY TO RISE TO
AROUND 105-111 F SUNDAY THROUGH TUESDAY. AN SPS FOR HEAT INDICES
OF AROUND 108-111 F IS POSSIBLE DURING THIS TIME AS MODERATE HEAT
RISKS PERSIST, WITH MAJOR HEAT RISKS POSSIBLE OVER THE COASTAL
COUNTIES ON MONDAY. MINOR TO MODERATE HEAT RISKS RESUME ON
WEDNESDAY AS SOUTHEASTERLY WINDS WEAKEN AND PWATS REMAIN LOW
BEFORE POTENTIALLY RISING AT THE END OF NEXT WEEK.
A MODERATE RISK OF LIFE-THREATENING RIP CURRENTS CONTINUES THROUGH
SUNDAY AFTERNOON, LIKELY TO PERSIST AND/OR ESCALATE TO A HIGH RISK
INTO THE BEGINNING OF THIS UPCOMING WEEK.
AVIATION
(06Z TAFS)
ISSUED AT 1241 AM CDT SUN JUN 21 2026
LIGHT SOUTHEAST TO SOUTH WINDS AND A MIX OF VFR/MVFR CEILINGS
PREVAIL ACROSS DEEP SOUTH TEXAS EARLY THIS MORNING. MAINLY MVFR
CEILINGS, A FEW BRIEF IFR CEILINGS WILL BE POSSIBLE, ARE EXPECTED
OVERNIGHT AT LOCAL AERODROMES. SOUTHEAST WINDS ARE FORECAST TO
INCREASE AND BECOME MODERATE TO GUSTY LATER THIS MORNING INTO THE
AFTERNOON. VFR CONDITIONS WILL RETURN MID TO LATE MORNING AND
CONTINUE THROUGH MUCH OF THE PERIOD. MVFR CEILINGS MAY RETURN
LATE IN THE PERIOD.
MARINE
ISSUED AT 1019 PM CDT SAT JUN 20 2026
SMALL CRAFT EXERCISE CAUTION (SCEC) CONDITIONS ARE LIKELY TO
CONTINUE THROUGH AT LEAST MONDAY NIGHT AS A TIGHTENED PRESSURE
GRADIENT RESULTS IN MODERATE TO FRESH, OCCASIONALLY STRONG,
SOUTHEASTERLY TO SOUTHERLY WINDS AND MODERATE (4-6 FT) SEAS. A SMALL
CRAFT ADVISORY IS NOT OUT OF THE QUESTION SUNDAY NIGHT INTO MONDAY
AS WINDS PEAK TO FRESH TO STRONG. FOLLOWING, MODERATE TO FRESH WINDS
RESUME TUESDAY, WITH PERIODS OF SCEC POSSIBLE THROUGH NEXT WEEKEND,
WHEN WINDS COULD RE-ENHANCE. WINDS MAY EASE JUST A BIT INTO THE
MIDDLE OF NEXT WEEK BEFORE PICKING BACK UP TOWARDS AND OVER THE
WEEKEND. A LOW TO MEDIUM (20-40%) CHANCE OF RAIN CONTINUES TONIGHT,
DROPPING TO LESS THAN 10% THROUGHOUT SUNDAY.
PRELIMINARY POINT TEMPS/POPS
BROWNSVILLE 93 83 95 83 / 20 0 0 0
HARLINGEN 94 80 96 80 / 20 0 0 0
MCALLEN 95 81 98 81 / 10 0 0 0
RIO GRANDE CITY 95 79 98 79 / 10 10 0 0
SOUTH PADRE ISLAND 89 84 90 83 / 20 0 0 0
BAYVIEW/PORT ISABEL 92 82 94 82 / 20 0 0 0
BRO WATCHES/WARNINGS/ADVISORIES
TX...NONE.
GM...NONE.
SHORT TERM...65-IRISH
LONG TERM....65-IRISH
AVIATION...63-KC
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