314  
FXUS64 KBRO 261118  
AFDBRO  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BROWNSVILLE TX  
618 AM CDT TUE MAY 26 2026  
   
..NEW AVIATION  
 
   
KEY MESSAGES  
 
UPDATED AT 614 AM CDT TUE MAY 26 2026  
 
KEY MESSAGES:  
 
* SPC CONTINUES A MARGINAL RISK (LEVEL 1 OF 5) OF ISOLATED SEVERE  
THUNDERSTORMS, WITH A PRIMARY THREAT OF DAMAGING WINDS, ACROSS  
ALL OF DEEP SOUTH TEXAS AS WELL AS A SECONDARY THREAT OF  
ISOLATED LARGE TO VERY LARGE HAIL ACROSS PORTIONS OF THE UPPER  
RGV AND RIO GRANDE PLAINS TUESDAY/TUESDAY NIGHT.  
 
* WPC MAINTAINS A MARGINAL RISK (LEVEL 1 OF 4) OF ISOLATED FLASH  
FLOODING FROM EXCESSIVE AND HEAVY RAINFALL ACROSS THE NORTHERN  
RANCHLANDS AND RIO GRANDE PLAINS ON TUESDAY/TUESDAY NIGHT AS  
WELL AS THE COASTAL COUNTIES AND PORTIONS OF THE NORTHERN  
RANCHLANDS AND MIDDLE RGV ON WEDNESDAY.  
 
* THERE ARE ADDITIONAL CHANCES OF STRONG TO ISOLATED SEVERE  
THUNDERSTORMS ON WEDNESDAY AND THURSDAY, THOUGH CONFIDENCE IS  
LOW AT THIS TIME. OTHERWISE, DRIER WEATHER RETURNS WEDNESDAY  
NIGHT AND THROUGH THE END OF THE WORK WEEK/EARLY WEEKEND.  
UNSETTLED WEATHER MAY RETURN LATER WEEKEND/EARLY NEXT WEEK.  
 
* DAILY MINOR TO MODERATE (LEVELS 1 AND 2 OF 4) HEAT RISKS AND  
MAXIMUM AFTERNOON HEAT INDICES OF 95-105 F (LOCALLY HOTTER)  
CONTINUE, POSSIBLY PEAKING OVER THE WEEKEND.  
 
* A LOW RISK OF RIP CURRENTS PERSISTS THROUGH TUESDAY AFTERNOON.  
 
 
   
DISCUSSION  
 
ISSUED AT 1026 PM CDT MON MAY 25 2026  
 
A STRONG MID/UPPER LEVEL TROUGH DIGS FROM THE PNW TO THE WESTERN US,  
ADVANCING ANOTHER TROUGH EASTWARD OVER THE DESERT SOUTHWEST TO  
WESTERN TEXAS BY MIDWEEK, THUS RESULTING IN A GRADUAL INCREASE IN  
FORCING AND ASCENSION ALOFT. THIS, ALONG WITH SOUTHEASTERLY FLOW RE-  
ENHANCING SURFACE MOISTURE BEGINNING TONIGHT, SHOULD BUILD CLOUD  
COVER ACROSS DEEP SOUTH TEXAS THROUGH THE NEXT 24 HOURS. AT THIS  
TIME, WE ANTICIPATE A LOW (15-30%) CHANCE OF SHOWERS AND THUNDERSTORMS  
DEVELOPING OVER THE RIO GRANDE PLAINS TUESDAY MORNING AND SPREADING  
EASTWARD ACROSS THE ENTIRE REGION INTO THE AFTERNOON AND EVENING  
HOURS. CHANCES OF RAIN COULD REACH AS HIGH AS A LOW TO MEDIUM  
(30-60%) CHANCE TUESDAY NIGHT, HIGHEST ACROSS THE NORTHERN RANCHLANDS.  
THIS IS MORE IN ALIGNMENT WITH THIS EVENING'S CAM GUIDANCE, WHICH  
NOW GENERALLY SUGGEST INCREASED CLOUD COVER AND REDUCED SURFACE-  
BASED INSTABILITY LEADING TO MORE STRATIFORM LIGHT TO MODERATE  
SHOWERS AND A FEW SUB-SEVERE, THOUGH POTENTIALLY LOCALLY STRONG,  
THUNDERSTORMS CAPABLE OF PRODUCING GUSTY WINDS AND LOCALLY  
HEAVIER RAIN THROUGH THE MORNING AND AFTERNOON HOURS ON TUESDAY  
BEFORE ANOTHER ROUND TUESDAY NIGHT, WHEN STRONG TO ISOLATED  
THUNDERSTORMS ARE POSSIBLE ACROSS THE RIO GRANDE PLAINS AND  
NORTHERN RANCHLANDS.  
 
YET, SHOULD A FURTHER DELAY IN THE ARRIVAL OF DIVERGENCE ALOFT  
RESULT IN MORE SPARSE CLOUD COVER AND LOWER RAIN CHANCES DURING THE  
DAY ON TUESDAY, THE PROBABILITIES OF STRONG TO ISOLATED SEVERE  
THUNDERSTORMS DURING THE AFTERNOON AND/OR OVERNIGHT HOURS COULD  
INCREASE CONSIDERABLY. THEREFORE, SPC CONTINUES A MARGINAL RISK OF  
ISOLATED SEVERE THUNDERSTORMS FOR TUESDAY AND TUESDAY NIGHT, WITH  
THE PRIMARY RISK OF ISOLATED DAMAGING (58+ MPH) WINDS ACROSS ALL  
OF DEEP SOUTH TEXAS AS WELL AS A SECONDARY THREAT OF ISOLATED  
LARGE (1+ INCH) HAIL ACROSS ZAPATA COUNTY AND THE FAR WESTERN  
PORTION OF STARR COUNTY IF SIERRA MADRE CONVECTION MAKES IT TO THE  
BORDER. VERY LARGE (2+ INCH) HAIL IS EVEN POSSIBLE NEAR AND ALONG  
THE RIO GRANDE/US BORDER IN NORTHERN ZAPATA COUNTY. THIS  
CONDITIONAL AND HYPOTHETICAL SCENARIO COULD ALSO BE SUPPORTIVE OF  
PRODUCING A SQUALL LINE ACROSS ALL, OR PORTIONS, OF THE CWA  
TUESDAY NIGHT. ADDITIONALLY, AS PWAT VALUES RISE TO AS MUCH AS 1.9  
TO 2.2 IN. TUESDAY INTO WEDNESDAY, WPC KEEPS THE MAJORITY OF THE  
NORTHERN RANCHLANDS AND THE RIO GRANDE PLAINS WITHIN A MARGINAL  
RISK OF ISOLATED FLASH FLOODING FROM EXCESSIVE AND HEAVY RAINFALL  
TUESDAY AND TUESDAY NIGHT. MORE SPECIFICALLY, THIS INCLUDES MOST  
OF ZAPATA COUNTY (EXCEPT THE SOUTHERN PORTIONS), ALL OF JIM HOGG  
COUNTY, MOST OF BROOKS COUNTY (EXCEPT THE SOUTHEASTERN AREAS) AND  
THE NORTHWESTERN PART OF KENEDY COUNTY.  
 
A LOW TO MEDIUM (30-60%) CHANCE OF SHOWERS AND THUNDERSTORMS  
CONTINUES THROUGH WEDNESDAY MORNING AND AFTERNOON AS THE TROUGH  
PASSES OVER OUR REGION. CURRENTLY, SPC OUTLINES A GENERAL OUTLOOKS  
OF SUB-SEVERE THUNDERSTORMS ON WEDNESDAY. HOWEVER, A STRONG TO  
SEVERE THUNDERSTORM, OR TWO, IS NOT OUT OF THE QUESTION,  
ESPECIALLY IF A POTENTIAL SQUALL LINE IS STILL WORKING ITS WAY  
THROUGH THE REGION INTO THE DAYTIME, PERHAPS OVER THE EASTERN  
PORTIONS OF THE CWA. AS SUCH, SPC COULD ADD A MARGINAL RISK WITHIN  
THE NEXT FEW UPDATES. WPC MAINTAINS A MARGINAL RISK OF ISOLATED  
FLASH FLOODING FROM EXCESSIVE RAINFALL FROM THE EASTERN HALF OF  
JIM HOGG AND HIDALGO COUNTIES ON EASTWARD TO THE COAST FOR  
WEDNESDAY. BY THURSDAY MORNING, WE EXPECT RAINFALL AMOUNTS TO  
RANGE FROM A TRACE TO AS MUCH AS 0.5 AN INCH ACROSS THE RGV, WHILE  
THE RIO GRANDE PLAINS AND THE NORTHERN RANCHLANDS COULD RECEIVE  
0.5 TO 0.8 OF AN INCH. HOWEVER, DUE TO VERY HIGH MOISTURE CONTENT  
FAVORING EFFICIENT HEAVY RAIN PRODUCTION, LOCALIZED RAINFALL  
RATES OF UP TO 3 IN./HR COULD PRODUCE 1 TO 3+ INCHES WITHIN THE  
DEEPEST CONVECTION, ESPECIALLY IN SLOW-MOVING THUNDERSTORMS OR  
WHERE THUNDERSTORMS TRAIN OVER AN AREA ONE AFTER THE OTHER.  
 
RIDGING BEHIND THE DEPARTING TROUGH RESUMES AND BRINGS MUCH DRIER  
CONDITIONS WEDNESDAY NIGHT. MINIMAL (<10%) CHANCES OF RAIN COULD  
PERSIST THROUGH THE REMAINDER OF THE WORK WEEK, POSSIBLY INTO  
SATURDAY. YET, THE 00Z RRFS AND 18Z GFS PORTRAY AN EMBEDDED MID-  
LEVEL SHORTWAVE PASSING OVER ON THURSDAY, BRINGING THE POSSIBILITY  
OF STRONG TO ISOLATED THUNDERSTORMS. HOWEVER, CONFIDENCE REMAINS  
LOW AT THIS TIME. OTHERWISE, THE NEXT CHANCE OF UNSETTLED WEATHER  
ARRIVES POSSIBLY SATURDAY NIGHT INTO NEXT MONDAY AS THE UPPER  
LEVEL TROUGH OVER THE WESTERN US ADVANCES EASTWARD. POPS ARE LOW  
TO MEDIUM AT THIS TIME. HIGH TEMPERATURES CONTINUE TO RISE TO THE  
UPPER 80S AND 90S ALONG WITH HEAT INDICES GENERALLY RANGING FROM  
95-105 F. MINOR TO MODERATE HEAT RISKS CONTINUE ACROSS THE RGV AND  
COASTAL COUNTIES, WHERE INDICES COULD BRIEFLY PEAK AS HIGH AS 110  
F. MORE ABUNDANT SUNSHINE RESULTS IN A MORE WIDESPREAD MODERATE  
HEAT RISK ON FRIDAY AND SATURDAY. OVERNIGHT LOWS CONTINUE IN THE  
70S.  
 
A LOW RISK OF RIP CURRENTS CONTINUES THROUGH TUESDAY AFTERNOON.  
 
 
   
AVIATION  
 
(12Z TAFS)  
ISSUED AT 614 AM CDT TUE MAY 26 2026  
 
THROUGH 12Z WEDNESDAY....VFR CONDITIONS, BY AND LARGE, WILL PREVAIL  
THROUGH THE 12Z TAF CYCLE. THE EXCEPTION COULD BE DURING THE  
OVERNIGHT HOURS INTO THE EARLY-MID MORNING HOURS WHERE MVFR-IFR  
MIST/LOW STRATUS COULD DEVELOP OR BE AROUND.  
 
RAIN OR THUNDERSHOWERS ARE POSSIBLE LATER THIS MORNING OVER ALL  
THE TERMINALS WITH THE GREATEST CHANCE BEING OVER KMFE. ANOTHER  
ROUND OF SHOWERS AND THUNDERSTORMS ARE POSSIBLE LATER TONIGHT INTO  
WEDNESDAY. CURRENTLY, HAVE PROB30 GROUPS FOR KMFE. ANY SHOWERS OR  
STORMS WILL HAVE THE CAPABILITIES OF REDUCING CIGS/VSBYS DOWN TO  
MVFR-IFR. WE'LL CONTINUE TO MONITOR TRENDS AND MAKE AMENDMENTS AS  
NEEDED.  
 
IF NOT LIGHT AND VARIABLE, WINDS WILL BE LIGHT OUT OF THE SOUTHEAST  
WITH SPEEDS UP TO 5 KTS THROUGH THE OVERNIGHT. DURING THE DAY TODAY,  
LIGHT AND VARIABLE WINDS ARE EXPECTED TO PICK UP OUT OF THE  
SOUTHEAST WITH SPEEDS BETWEEN 5-15 KTS AND GUSTS UP TO 25 KTS.  
 
 
   
MARINE  
 
ISSUED AT 1026 PM CDT MON MAY 25 2026  
 
GENTLE TO MODERATE EASTERLY TO SOUTHEASTERLY WINDS AND SLIGHT TO  
MODERATE (2-4 FT, OCCASIONALLY HIGHER) SEAS PERSIST THROUGH THE  
NEXT 7 DAYS. SMALL CRAFT EXERCISE CAUTION HEADLINES ARE POSSIBLE FOR  
THE LAGUNA MADRE AND NEARSHORE GULF WATERS (0-20 NM) TUESDAY AND  
WEDNESDAY AFTERNOON/EVENING IN RESPONSE TO A SLIGHT LOCALLY  
ENHANCED PRESSURE GRADIENT, RESULTING IN MODERATE TO FRESH WINDS.  
CHANCES OF SHOWERS AND THUNDERSTORMS INCREASE TUESDAY NIGHT TO AS  
MUCH AS A LOW TO MEDIUM (3-60%) CHANCE DURING THE DAY ON WEDNESDAY.  
STRONG TO ISOLATED SEVERE THUNDERSTORMS ARE POSSIBLE AS WELL.  
CHANCES GRADUALLY DIMINISH WEDNESDAY NIGHT AND MUCH DRIER  
CONDITIONS RESUME THROUGH THIS WEEKEND BEFORE THE NEXT SYSTEM  
BRINGS UNSETTLED WEATHER, POSSIBLY BY EARLY NEXT WEEK.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
BROWNSVILLE 90 80 91 79 / 10 20 30 20  
HARLINGEN 91 77 91 75 / 20 30 40 10  
MCALLEN 91 78 93 77 / 20 40 30 10  
RIO GRANDE CITY 91 75 94 75 / 20 40 10 10  
SOUTH PADRE ISLAND 85 81 86 80 / 10 30 30 20  
BAYVIEW/PORT ISABEL 89 79 90 78 / 10 30 40 20  
 
 
   
BRO WATCHES/WARNINGS/ADVISORIES  
 
TX...NONE.  
GM...NONE.  
 
 
 
 
SHORT TERM...65  
LONG TERM....65  
AVIATION...23-EVBUOMA  
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