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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