585  
FXUS64 KBRO 181110  
AFDBRO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BROWNSVILLE TX  
610 AM CDT MON AUG 18 2025  
   
..NEW AVIATION  
 
   
DISCUSSION  
 
ISSUED AT 1051 PM CDT SUN AUG 17 2025  
 
DESPITE SOME SUBTLE DIFFERENCES, THE FORECAST OVER THE NEXT 7 DAYS  
CONTINUES TO FEATURE A WEAK MID-LEVEL HIGH PRESSURE OVER THE CENTRAL  
PLAINS SHIFTING WESTWARD AND EXPANDING ACROSS THE FOUR CORNERS  
REGION BY TUESDAY. AS A RESULT, DRY CONDITIONS CONTINUE ACROSS THE  
CWA THROUGH MONDAY, WITH POP'S REMAINING BELOW 10%. MEANWHILE, MID-  
LEVEL TROUGHING EXPANDS OVER THE GULF, BRINGING AN UPWARD TREND IN  
MOISTURE, WITH PROBABILITIES INCREASING FROM A LOW (20-30%) CHANCE  
OF SHOWERS AND THUNDERSTORMS ON TUESDAY TO A LOW TO MEDIUM (30-50%)  
CHANCE ON WEDNESDAY, FOLLOWED BY A 20-40% CHANCE ON THURSDAY. LATER  
IN THE WEEK, A TROUGH OVER THE MID-ATLANTIC EXTENDS SOUTHWESTWARD,  
FURTHER ELEVATING PWAT VALUES TO NEAR AND ABOVE 2.0 INCHES,  
RESULTING IN A 30-50% CHANCE ON FRIDAY AND OVER THE WEEKEND.  
THROUGHOUT THE WEEK, CONVECTION IS EXPECTED TO BE DIURNALLY DRIVEN  
AND BRIEF IN NATURE, OCCURRING ALONG THE SEABREEZE BOUNDARY IN THE  
LATE MORNING AND AFTERNOON HOURS WITH THE HIGHEST PROBABILITIES  
ALONG AND EAST OF US-281/I-69 C, BECOMING MORE WIDESPREAD IN  
COVERAGE INTO THE WEEKEND. AS PWAT'S INCREASE, ANY CONVECTION THAT  
DEVELOPS BRINGS THE POSSIBILITY OF BRIEF HEAVY DOWNPOURS, LIGHTNING  
AND GUSTY WINDS. THIS WET PATTERN MAY CONTINUE INTO THE BEGINNING OF  
NEXT WEEK, THOUGH POTENTIALLY BEGINNING TO SHUT OFF AS RECENT RUNS  
OF THE DETERMINISTIC GFS AND ECMWF HINT AT AN EASTWARD EXPANSION OF  
THE MID-LEVEL HIGH RESIDING OVER THE DESERT SOUTHWEST.  
 
HIGH TEMPERATURES CONTINUE TO RANGE FROM NEAR TO SLIGHTLY ABOVE  
AVERAGE WITH MID 80'S AT THE BEACHES, MID TO UPPER 90'S ALONG AND  
EAST OF I-69 E AS WELL AS NEARLY WIDESPREAD LOWER 100'S FURTHER WEST  
AT LEAST INTO TUESDAY. FOLLOWING, CLOUD COVERAGE AND PROBABILITIES  
OF RAIN INCREASE, RESULTING IN 90'S ACROSS ALL OF INLAND DEEP SOUTH  
TEXAS AND THE RIO GRANDE VALLEY BY THE WEEKEND, WHILE MID 80'S  
CONTINUE ALONG THE IMMEDIATE COAST. MOSTLY A MODERATE (LEVEL 2/4)  
HEAT RISK IS EXPECTED MONDAY AND TUESDAY, FOLLOWED BY A MINOR (LEVEL  
1/4) TO MODERATE HEAT RISK WEDNESDAY, THROUGH THE WEEKEND AND INTO  
NEXT MONDAY AS AFTERNOON HEAT INDICES GENERALLY REMAIN BETWEEN 100  
AND 109 DEGF, THOUGH A FEW LOCATIONS MAY EXPERIENCE HIGHER APPARENT  
TEMPERATURES FOR A BRIEF PERIOD OF TIME. AT THIS TEAM, HEAT INDICES  
ARE BORDERLINE SPECIAL WEATHER STATEMENT CRITERIA FOR MONDAY ACROSS  
PORTIONS OF THE COASTAL COUNTIES AND RIO GRANDE VALLEY, THOUGH NOT  
AS HIGH OF A LIKELIHOOD AS TODAY.  
 
THERE IS A LOW RISK OF RIP CURRENTS THROUGH MONDAY.  
 
 
   
AVIATION  
 
(12Z TAFS)  
ISSUED AT 610 AM CDT MON AUG 18 2025  
 
THROUGH 12Z TUESDAY.....COPIOUS AMOUNTS OF LOW LEVEL MOISTURE FROM  
RECENT RAINS COUPLED WITH LIGHT WINDS AND MAINLY CLEAR SKIES  
OVERNIGHT HAVE ONCE AGAIN RESULTED IN THE DEVELOPMENT OF SOME LOW  
STRATUS AND/OR MIST/FOG OVER PARTS OF THE REGION. LATEST GOES-19  
NIGHTTIME FOG AND MICROPHYSICS CHANNELS CONFIRMS THIS. AS OF THIS  
UPDATE, KHRL WAS REPORTING LIFR CONDITIONS DUE TO 1/2 STATUTE MILE  
VISIBILITIES FROM FOG AND CIGS BETWEEN 500-1,000 FEET AGL. HAVE  
APPLIED A TEMPO GROUP FROM 10Z-13Z FOR KHRL TO ACCOUNT FOR THE  
MIST/FOG AND/OR LOW STRATUS.  
 
ANY MIST/FOG/LOW STRATUS FROM THIS EARLY THIS MORNING WILL GRADUALLY  
SCOUR OR BURN OFF BY MID MORNING GIVING WAY TO A RETURN TO MOSTLY  
VFR CONDITIONS AT ALL OF THE LOCAL TERMINALS THROUGH THE REST OF THE  
DAY. IT'S POSSIBLE THAT THERE COULD BE A FEW MVFR CLOUDS AROUND,  
ESPECIALLY THIS MORNING.  
 
LATER TONIGHT, MOST TAF SITES WILL REMAIN VFR, HOWEVER, THERE MAY  
ONCE AGAIN BE A LOW, NON-ZERO PROBABILITY FOR SOME PATCHY MIST/FOG  
OR EVEN LOW STRATUS DEVELOPING DUE TO NARROWING DEWPOINT DEPRESSIONS  
FROM THE COMBINATION OF STILL LARGE AMOUNTS OF LOW LEVEL MOISTURE IN  
PLACE, SOME RADIATIONAL COOLING FROM CLEARING SKIES, AND LIGHT WINDS.  
 
LIGHT AND VARIABLE TO CALM WINDS THIS MORNING WILL BECOME  
SOUTHEASTERLY WITH SPEEDS BETWEEN 5-15 KTS THROUGH THE 12Z TAF  
PERIOD. WINDS COULD GUST AS HIGH AS 20 KTS DURING THE AFTERNOON  
HOURS BEFORE WANING LATER IN THE EVENING.  
 
 
   
MARINE  
 
ISSUED AT 1051 PM CDT SUN AUG 17 2025  
 
MAINLY LIGHT TO GENTLE, MODERATE AT TIMES, SOUTHEASTERLY WINDS AND  
SLIGHT (1-2 FEET) SEAS ARE EXPECTED TO PREVAIL THROUGHOUT THE  
PERIOD, LEAVING FOR FAVORABLE MARINE CONDITIONS. DAILY PROBABILITIES  
OF BRIEF SHOWERS AND THUNDERSTORMS INCREASE TO A LOW (20-30%) CHANCE  
TUESDAY, INCREASING TO A LOW TO MEDIUM (30-50%) CHANCE OVER THE  
WEEKEND.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
BROWNSVILLE 96 77 96 78 / 10 0 20 10  
HARLINGEN 97 74 98 73 / 10 0 20 10  
MCALLEN 101 78 101 78 / 10 0 20 10  
RIO GRANDE CITY 103 76 103 77 / 0 0 10 20  
SOUTH PADRE ISLAND 88 80 88 80 / 10 0 20 20  
BAYVIEW/PORT ISABEL 92 76 92 77 / 10 0 20 10  
 
 
   
BRO WATCHES/WARNINGS/ADVISORIES  
 
TX...NONE.  
GM...NONE.  
 
 
 
 
SHORT TERM...65-IRISH  
LONG TERM....65-IRISH  
AVIATION...23-EVBUOMA  
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