272  
FXUS64 KBRO 202326 AAA  
AFDBRO  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE BROWNSVILLE TX  
626 PM CDT SAT APR 20 2024  
   
..NEW AVIATION
 
 
   
SHORT TERM
 
 
(TONIGHT THROUGH SUNDAY NIGHT)  
ISSUED AT 121 PM CDT SAT APR 20 2024  
 
THIS MORNING'S SCATTERED SHOWERS AND THUNDERSTORMS, ASSOCIATED WITH  
A WEAK DISTURBANCE EMBEDDED WITHIN THE FLOW ALOFT, HAS COME TO AN  
END AS OF EARLY THIS AFTERNOON AS THE DISTURBANCE EXITS TO THE EAST.  
LOW LEVEL EASTERLY TO SOUTHEASTERLY FLOW WILL CONTINUE TO TRANSPORT  
GULF MOISTURE ACROSS THE REGION THIS AFTERNOON, ALLOWING FOR  
PRECIPITABLE WATER VALUES TO REMAIN AROUND OR ABOVE THE 90TH  
PERCENTILE FOR THIS TIME OF YEAR. THE 12Z BRO SOUNDING MEASURED A  
PWAT VALUE OF 1.73 INCHES, AND MOST HIGH RES GUIDANCE INDICATES  
PWATS SHOULD REMAIN HIGH THROUGH TONIGHT. MEANWHILE, A COLD FRONT,  
CURRENTLY MOVING ACROSS THE TEXAS HILL COUNTRY, IS EXPECTED TO MAKE  
ITS WAY TOWARD DEEP SOUTH TEXAS LATE THIS EVENING AS AN UPPER LEVEL  
DISTURBANCE TRACKS ACROSS MUCH OF THE STATE THIS AFTERNOON THROUGH  
TONIGHT.  
 
ALTHOUGH WE'LL HAVE HIGH MOISTURE CONTENT IN PLACE AHEAD OF  
THE COLD FRONT, THE BETTER FORCING FOR ASCENT WILL BE LOCATED WELL  
NORTH OF THE REGION WHICH MAY LIMIT THE OVERALL POTENTIAL FOR STRONG  
TO SEVERE THUNDERSTORMS AS THE COLD FRONT APPROACHES TONIGHT.  
HOWEVER, HIGH RES MODEL SOUNDINGS REVEAL MUCAPE VALUES RANGING FROM  
1500-2000 J/KG ACROSS THE RIO GRANDE VALLEY AND CLOSER TO 2000-2500  
J/KG ACROSS THE NORTHERN RANCHLANDS, MID-LEVEL LAPSE RATES RANGING  
FROM 7-8 C/KM, AND 0-6 KM SHEAR AROUND 30 KNOTS. THIS WOULD SUPPORT  
AT LEAST A LIMITED THREAT FOR SEVERE THUNDERSTORMS TONIGHT WITH  
PRIMARILY A DAMAGING WIND AND HAIL THREAT, PRIMARILY ACROSS THE  
NORTHERN RANCHLANDS AND RIO GRANDE PLAINS. HREF MEMBERS CONTINUE TO  
VARY IN SOLUTIONS ON PRECIPITATION AND THUNDERSTORM COVERAGE FOR  
TONIGHT INTO EARLY SUNDAY MORNING, BUT ARE IN GENERAL AGREEMENT ON  
THE ONSET OF PRECIPITATION ACROSS THE NORTHERN RANCHLANDS BEGINNING  
AROUND OR AFTER 9 PM AND AFTER MIDNIGHT FOR THE RGV.  
 
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL LINGER THROUGH THE  
MORNING AND EARLY AFTERNOON HOURS ACROSS THE RIO GRANDE VALLEY AS  
WARM, HUMID AIR RISES ABOVE THE SOUTHWARD MOVING COLD FRONT. THE  
COMBINATION OF LINGERING PRECIPITATION, CLOUD COVER, AND ARRIVAL OF  
BRISK NORTH WINDS SHOULD RESULT IN A NOTICEABLY COOL SUNDAY ACROSS  
ALL OF DEEP SOUTH TEXAS. HIGH TEMPERATURES WILL TOP OUT IN THE UPPER  
60S ACROSS THE NORTHERN RANCHLANDS AND LOW 70S ACROSS THE RGV, WITH  
THE HIGH TEMPERATURE LIKELY OCCURRING DURING THE MORNING HOURS.  
GUIDANCE INDICATES TEMPERATURES WILL STEADILY FALL THROUGH THE  
AFTERNOON INTO THE 60S WITH THE ARRIVAL OF THE COOLER AIRMASS. WIND  
GUSTS AROUND 20-30 MPH WILL BE LIKELY BEGINNING BY MID TO LATE  
SUNDAY MORNING, AND SHOULD BEGIN TO SUBSIDE BY THE EVENING HOURS AS  
THE PRESSURE GRADIENT SLACKENS. LOW TEMPERATURES WILL FALL INTO THE  
MID 50S ACROSS THE RIO GRANDE PLAINS INTO THE LOW 60S ACROSS THE RIO  
GRANDE VALLEY SUNDAY NIGHT INTO MONDAY MORNING. ADDITIONAL LIGHT  
PRECIPITATION CANNOT BE RULED OUT SUNDAY NIGHT, MAINLY OVER THE RGV.  
 
FOR THE LOWER TEXAS BEACHES, A MODERATE TO HIGH RISK OF RIP CURRENTS  
IS LIKELY BEGINNING SUNDAY DUE TO INCREASING SEAS.  
 

 
   
LONG TERM
 
 
(MONDAY THROUGH NEXT SATURDAY)  
ISSUED AT 121 PM CDT SAT APR 20 2024  
 
THE GENERAL FORECAST TREND FOR THE LONG TERM...STARTS OFF COOL  
AND DAMP MONDAY FOLLOWED BY A DRIER AND WARMER PERIOD. MODELS ARE  
IN GOOD AGREEMENT WITH THE CENTER OF A COOL SURFACE RIDGE OVER  
THE ARKLATEX MONDAY MORNING WITH SUNDAY'S FRONTAL BOUNDARY NOT TO  
FAR SOUTH OVER THE GULF. PERSISTENT NORTHEAST SURFACE WINDS AND  
MID-LEVEL OVERRUNNING (S-SW WINDS AT 800-700MB) PRODUCING A  
THICK OVERCAST AND PROVIDING A LINGERING CHANCE OF LIGHT RAIN  
MAINTAINS BELOW NORMAL TEMPERATURES. MODEL GUIDANCE IS SUGGESTING  
HIGHS ONLY 69-74 ACROSS DEEP SOUTH TEXAS WHICH IS 15-20 DEGREE  
BELOW MID APRIL AVERAGES. PROBABILITY OF ANY LOCATION SEEING  
HIGH TEMPERATURES OVER 75 DEGREES MONDAY ARE ONLY 10-15 PERCENT.  
 
ONE MORE COOL MORNING TUESDAY, UPPER 50S TO LOWER 60S, BEFORE  
THIS COOL SHOT DEPARTS AND A WARMING TREND COMMENCES. 500MB RIDGE  
BUILDS OVER THE ROCKIES AND SPREADS EASTWARD OVER TEXAS THURSDAY  
AND OVER THE WESTERN GULF OF MEXICO FRIDAY AND SATURDAY. SURFACE  
WINDS RETURN FROM THE SOUTHEAST TUESDAY MORNING WITH THE SURFACE  
HIGH PRESSURE SETTLING ALONG THE EAST COAST. PRESSURE GRADIENT IS  
MODERATE AT BEST THROUGH THURSDAY WITH A TIGHTENING OF THE  
GRADIENT FRIDAY AND SATURDAY AS THE NEXT UPSTREAM STORM SYSTEM  
TAKES SHAPE. ALL MODEL GUIDANCE WARMS UP HIGH AND LOW TEMPERATURES  
NEAR NORMAL WEDNESDAY, GOING ABOVE NORMAL THURSDAY THROUGH  
SATURDAY.  
 

 
   
AVIATION
 
 
(00Z TAFS)  
ISSUED AT 622 PM CDT SAT APR 20 2024  
 
VFR CONDITIONS ARE EXPECTED TO GIVE WAY TO MVFR AND IFR CEILINGS  
TONIGHT AS A COLD FRONT APPROACHES FROM THE NORTH. THUNDERSTORMS  
ARE POSSIBLE, MAINLY WEST OF MFE INTO MID MORNING SUNDAY. THIS MAY  
BRING A PERIOD OF LIFR CONDITIONS. BREEZY NORTHEASTERLY WINDS  
FOLLOW INTO SUNDAY AFTERNOON WITH PERSISTENT CLOUD COVER THROUGH  
THE TAF PERIOD.  
 

 
   
MARINE
 
 
ISSUED AT 121 PM CDT SAT APR 20 2024  
 
NOW THROUGH SUNDAY NIGHT...GENERALLY FAVORABLE MARINE CONDITIONS ARE  
EXPECTED THROUGH TONIGHT, ALTHOUGH THERE WILL BE A POTENTIAL FOR  
SCATTERED SHOWERS AND THUNDERSTORMS AHEAD OF AND ALONG A COLD FRONT.  
INCREASING WINDS AND BUILDING SEAS IN WAKE OF THE FRONTAL PASSAGE  
WILL RESULT IN SMALL CRAFT EXERCISE CAUTION CONDITIONS BEGINNING  
EARLY SUNDAY MORNING AND SMALL CRAFT ADVISORY CONDITIONS ALONG THE  
LAGUNA MADRE AND GULF WATERS BY MID TO LATE SUNDAY MORNING THROUGH  
THE END OF THE PERIOD. ADDITIONAL SCATTERED SHOWERS AND ISOLATED  
THUNDERSTORMS WILL BE POSSIBLE THROUGH SUNDAY NIGHT.  
 
MONDAY THROUGH SATURDAY...ADVERSE WEATHER CONDITIONS ARE EXPECTED  
AT THE BEGINNING OF THIS PERIOD (MONDAY MORNING) WITH A STEADY  
IMPROVEMENT MONDAY AFTERNOON AS SURFACE HIGH PRESSURE SETTLES OVER  
THE NORTHWEST GULF. BY TUESDAY, SURFACE RIDGE IS EXPECTED TO BE  
WELL EAST OF THE TEXAS COAST WITH VEERING WINDS BECOMING LIGHT AND  
SEAS BECOMING SLIGHT. THEREAFTER, WEDNESDAY AND THURSDAY LIGHT TO  
MODERATE SOUTHEAST WINDS WITH A MODEST GRADIENT ACROSS THE  
WESTERN GULF. PRESSURE GRADIENT BEGINS TO STRENGTHEN FRIDAY AND  
SATURDAY AS THE NEXT STORM SYSTEM MOVES INTO THE CENTRAL PLAINS.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
BROWNSVILLE 73 74 65 72 / 30 50 30 30  
HARLINGEN 71 71 60 73 / 30 40 20 30  
MCALLEN 70 72 61 73 / 40 40 20 30  
RIO GRANDE CITY 68 69 59 70 / 50 40 20 30  
SOUTH PADRE ISLAND 72 73 67 70 / 30 50 30 30  
BAYVIEW/PORT ISABEL 72 72 64 72 / 30 40 30 20  
 

 
   
BRO WATCHES/WARNINGS/ADVISORIES
 
 
TX...NONE.  
GM...SMALL CRAFT ADVISORY FROM 7 AM TO 10 PM CDT SUNDAY FOR GMZ130-  
132-135.  
 
SMALL CRAFT ADVISORY FROM 7 AM SUNDAY TO 7 AM CDT MONDAY FOR  
GMZ150-155-170-175.  
 

 
 

 
 
SHORT TERM...22-GARCIA  
LONG TERM....59-GB  
AVIATION...56-HALLMAN  
 
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