504  
FXUS64 KBRO 270524 AAB  
AFDBRO  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE BROWNSVILLE TX  
1124 PM CST FRI FEB 26 2021  
   
DISCUSSION
 
UPDATED FOR LATEST AVIATION DISCUSSION BELOW.  
 

 
   
AVIATION
 
MODERATE SOUTHEAST WINDS AND INCREASING LOW LEVEL CLOUD  
DECKS PREVAIL ACROSS DEEP SOUTH TEXAS LATE THIS EVENING. MVFR/IFR  
CEILINGS WILL DEVELOP OVERNIGHT AND CONTINUE THROUGH MID TO LATE  
SATURDAY MORNING. SOUTHEAST WINDS WILL INCREASE AND BECOME BREEZY BY  
MID MORNING AND PERSIST THROUGH SATURDAY AFTERNOON. VFR CONDITIONS  
WILL PREVAIL SATURDAY AFTERNOON BEFORE MVFR CEILINGS RETURN SATURDAY  
EVENING.  
 

 
   
PREV DISCUSSION
 
/ISSUED 535 PM CST FRI FEB 26 2021/  
 
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.  
 
AVIATION...MODERATE TO GUSTY SOUTHEAST WINDS WITH SOME PASSING  
HIGH CLOUDS PREVAIL ACROSS DEEP SOUTH TEXAS EARLY THIS EVENING.  
WINDS WILL BECOME LIGHT TO MODERATE LATER THIS EVENING INTO THE  
OVERNIGHT HOURS. LOW CLOUDS WILL RETURN LATER THIS EVENING  
DROPPING CEILINGS TO MVFR OVERNIGHT THROUGH MID TO LATE SATURDAY  
MORNING. BREEZY SOUTHEAST WINDS WILL DEVELOP BY MID MORNING AND  
PERSIST THROUGH SATURDAY AFTERNOON.  
 
PREV DISCUSSION... /ISSUED 216 PM CST FRI FEB 26 2021/  
 
SHORT TERM (NOW THROUGH SATURDAY NIGHT): A WEAK FRONT HAS SLICED  
OFF A SECTION OF THE UPPER VALLEY, WITH CLOUDS OVER THAT AREA AND  
THE ACCOMPANYING SLIGHTLY LOWER TEMPERATURES. THOUGH THE BOUNDARY  
MAY LINGER ACROSS THE NORTHERN AREAS THROUGH SATURDAY, THAT  
SHOULD PRETTY MUCH BE THE END OF THE LINE FOR THE WEAK FRONT AS IT  
THEN WILL BE FORCED FARTHER NORTH BY MORE SOLID SOUTHEAST WINDS.  
ISOLATED COASTAL SHOWERS WILL BE POSSIBLE SATURDAY MORNING, BUT  
THOSE WERE LEFT SILENT IN THE FORECAST FOR NOW. MARINE FOG MAY  
DRIFT OVER SOUTH PADRE ISLAND, PARTICULARLY OVERNIGHT, BUT  
FORMATION WILL CONFINE ITSELF TO THE COOLER NEARSHORE GULF WATERS.  
THAT SAID, VERY WARM, SEVERAL DEGREES ABOVE NORMAL WEATHER WILL  
SET UP ON SATURDAY, WITH AFTERNOON HIGH TEMPERATURES IN THE 80S TO  
NEAR 90, THOUGH 70S AT THE BEACHES. OVERNIGHT LOWS TONIGHT AND  
SATURDAY NIGHT WILL BE IN THE 60S.  
 
LONG TERM (SUNDAY THROUGH FRIDAY)...THE WEEKEND AND THE MONTH  
OVERALL GOES OUT LIKE A LAMB AFTER QUITE THE LION AT THE MIDDLE OF  
THE MONTH: WARM, BREEZY, WITH A MIX OF CLOUDS AND SUNSHINE DURING  
THE DAY AND MUGGY AND OVERCAST OVERNIGHT.  
 
BY MONDAY, THE NEXT FRONT APPROACHES...AND WHILE MODELS AGREE ON  
THE FRONT AND CHANGE OF AIRMASS BEHIND IT...THEY DISAGREE ON THE  
TIMING DETAILS. NAM/ECMWF ARE IN THE LATER CAMP...FOR THE NAM-12,  
WITH SHALLOW COOL AIR, THIS IS SOMEWHAT UNUSUAL...WHILE THE GFS IS  
FASTER. IN SHORT, THE LATER MODELS HOLD THE PASSAGE UNTIL SUNSET  
OR JUST BEYOND FOR THE POPULATED RGV, WHILE THE GFS HAS IT  
THROUGH BETWEEN 1 AND 4 PM WITH A NOTABLE DROP IN TEMPERATURES IF  
IT VERIFIES. FOR NOW, HAVE CONTINUED TO SPLIT THE DIFFERENCE AND  
LEANED TOWARD THE END OF DAY PASSAGE WHICH WOULD ALLOW ONE MORE  
ABOVE AVERAGE DAY BEFORE READINGS FALL A BIT MORE SHARPLY DURING  
THE EVENING. THIS SAID...WILL TWEAK WITH LATER FORECASTS AND WOULD  
NOT SURPRISED TO SEE TEMPERATURES REACH THEIR MAXES AT NOON  
(UPPER 70S OR SO) BEFORE TUMBLING THROUGH THE 60S AND PERHAPS INTO  
THE UPPER 50S BY SUNSET.  
 
AS FOR PRECIPITATION? CURRENTLY CARRYING LOW CHANCES FOR  
SHOWERS/STORMS ALONG THE FRONT BUT LATEST RUNS SUGGEST THE MORE  
TYPICAL POST-FRONTAL RAINS. SOME DECENT FORCING AND ELEVATED CAPE  
THAT COULD KEEP THUNDER GOING BEHIND FRONT IN THE AFTERNOON IF IT  
ARRIVES THAT SOON.  
 
MONDAY NIGHT AND TUESDAY LOOK CLOUDY WITH OCCASIONAL LIGHT RAIN  
OR DRIZZLE. MODELS NOT VERY BULLISH ON QPF SO WE'RE NOT EITHER...  
AND THOUGH AIR MASS IS *NOT* FROM THE POLE THIS TIME, IT WILL  
COOL DOWN A BIT AND HAVE LOWERED TUESDAY'S HIGHS IN ACCORDANCE  
WITH MODEL TRENDS...NOW LOW TO MID 60S.  
 
FOR WEDNESDAY THROUGH FRIDAY...QUICK RETURN TO EAST, THEN SOUTHEAST,  
FLOW WILL WARM THINGS UP BACK TO AROUND AVERAGE WEDNESDAY AND  
ABOVE AVERAGE THURSDAY. UNCERTAINTY ON THE NEXT FRONT/WIND SHIFT  
THEREAFTER...WHICH LOOKS DRY WITH MAINLY A DEWPOINT DROP BETWEEN  
LATE THURSDAY AND FRIDAY AS TEMPERATURES STAY ABOUT 3 TO 5 DEGREES  
ABOVE AVERAGE.  
 
MARINE:  
NOW THROUGH SATURDAY NIGHT...MODERATE SOUTHEAST WINDS AND  
MODERATE SEAS WILL PREVAIL THROUGH SATURDAY NIGHT. PESKY MARINE  
FOG WILL CONTINUE TO BE THE PRIMARY CONCERN OVER THE LOWER TEXAS  
COASTAL WATERS, AND KEPT MENTION GOING FOR THE ENTIRE PERIOD.  
ADDITIONAL DENSE FOG ADVISORIES MAY BE NEEDED.  
 
SUNDAY THROUGH WEDNESDAY NIGHT...MARINE LAYER OVER COOLER  
NEARSHORE WATERS AND LESSER GRADIENT FARTHER OFFSHORE SHOULD KEEP  
SPEEDS IN THE 10-15 KNOT RANGE...THOUGH LAGUNA MADRE LIKELY TO  
POKE 20 KNOTS GUSTS FOR CAUTION CONDITIONS SUNDAY INTO SUNDAY  
NIGHT. COULD SEE A BRIEF BOOST OVER THE GULF SUNDAY NIGHT BEFORE  
SLACKENING MONDAY AHEAD OF THE FRONT.  
 
THE MAIN STORY WILL BE THE FRONT...WHICH LOOKS TO BRING A PERIOD  
OF 20+ KNOT WIND AND SEAS TO 7 FEET OVER THE GULF MAINLY MONDAY  
NIGHT INTO EARLY TO MIDDAY TUESDAY...BEFORE A SLOW DROP IN SEAS  
AND MORE RAPID DROP IN WINDS AS DIRECTION VEERS TO EAST BY  
WEDNESDAY. CONVECTION LOOKS TO BE HELD TO A SHORT PERIOD MONDAY  
AFTERNOON/EVENING FOLLOWED BY LIGHTER RAINS TUESDAY. SEA FOG WILL  
CONTINUE TO BE PESKY NEARSHORE AND LAGUNA MADRE UNTIL THE FRONT  
SWEEPS THROUGH MONDAY EVENING.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
BAYVIEW/PORT ISABEL 66 78 67 78 / 0 0 0 10  
BROWNSVILLE 68 81 69 82 / 0 0 0 10  
HARLINGEN 67 83 68 83 / 0 0 0 10  
MCALLEN 67 86 68 86 / 0 0 0 10  
RIO GRANDE CITY 67 89 68 88 / 0 0 0 10  
SOUTH PADRE ISLAND 66 71 68 73 / 0 0 0 10  
 

 
   
BRO WATCHES/WARNINGS/ADVISORIES
 
 
TX...NONE.  
GM...DENSE FOG ADVISORY UNTIL 10 AM CST SATURDAY FOR GMZ130-132-135-  
150-155.  
 

 
 

 
 
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:  
HTTP://WEATHER.GOV/RGV  
 
63-KC/AVIATION  
 
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