Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 261153
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
553 AM CST THU FEB 26 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

&&

.AVIATION...VFR CURRENTLY AT BRO AND MFE WITH HRL ENCOUNTERING
SHALLOW GROUND AND FIELD FOG WITH VISIBILITIES OF LESS THAN ONE
MILE IN AND AROUND THE ASOS SENSOR. WOULD SUSPECT THIS TO
CONTINUE TO JUST AFTER DAWN THEN A RETURN TO VFR AT ALL TAF SITES
THROUGH THE REST OF THE AFTERNOON. A COLD FRONT WILL MOVE THROUGH
RETURNING THE WINDS TO THE NORTHEAST WITH A FEW GUSTS TO 22 KNOTS
IN THE AFTERNOON. CLOUDS WILL INCREASE BEHIND THE FRONT WITH
OVERRUNNING COMMENCING AND LOW CLOUDS DEVELOPING. SREF LOW CLOUD
PRODUCT SHOWS INCREASING CHANCES FOR MVFR CIGS TO MOVE IN AFTER
MIDNIGHT AND HAVE BUILT THIS INTO THE TAFS.

&&

.PREV DISCUSSION... /ISSUED 331 AM CST THU FEB 26 2015/

SHORT TERM /NOW THROUGH FRIDAY/...UPPER TROF PROGGED TO MOVE ACROSS
THE CENTRAL PLAINS TODAY WHICH WILL AID IN PUSHING A COLD FRONT
ACROSS DEEP SOUTH TEXAS LATE TODAY AND TONIGHT. NOT MUCH IN THE WAY
OF AVAILABLE MOISTURE SO ANTICIPATING A DRY FRONTAL PASSAGE. WITH
THE LATE PASSAGE OF THE FRONT HIGH TEMPERATURES WILL BE ABLE TO WARM
TO NEAR 70 DEGREES WITH LITTLE IN THE WAY OF CLOUDS. ONCE THE FRONT
MOVES THROUGH COOL CANADIAN HIGH PRESSURE WILL NOSE INTO OUR AREA
WITH NORTHEAST WINDS RETURNING AND A FEW HOURS OF GUSTS TO NEAR 25
MPH. THE FRONT MOVES SOUTH OF THE REGION TONIGHT WITH INCREASING
CLOUDS AND INCREASING ISENTROPIC LIFT. PRECIPITATION LOOKS TO HOLD
OFF UNTIL FRIDAY MORNING. BASED ON INCREASED CLOUDS DID SLIGHTLY
RAISE LOW TEMPERATURES IN THE VALLEY BUT LEFT RANCHLAND LOW
TEMPERATURES ALONE. 295-300K ISENTROPIC LIFT AND LOW CONDENSATION
PRESSURE DEFICITS WILL LEAD TO INCREASED CHANCES FOR LIGHT RAIN
ACROSS MUCH OF DEEP SOUTH TEXAS FRIDAY. SLIGHT CHANCE TO CHANCE POPS
LOOK REASONABLE WITH AMOUNTS ON THE LIGHT SIDE. ABUNDANT CLOUD COVER
WILL HOLD TEMPERATURES IN THE 40S AND 50S.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...TEMPS MUCH CLOSER TO
NORMAL WILL BE ON TAP ACROSS THE CWA FRIDAY NIGHT AS STRONG HIGH
PRESSURE TO THE NORTH SLIDES EAST WITH LOCAL WINDS VEERING TO EAST.
THE BROAD TROUGHING SEEN OVER MUCH OF THE CENTER OF THE COUNTRY WILL
FLATTEN OUT A BIT AS A SHARP SHORT WAVE TROUGH DESCENDS ALONG THE
WEST COAST...SUPPORTING LOW PRESSURE OVER THE SOUTHWEST UNITED
STATES. LIGHT RAIN CHANCES WILL CONTINUE FRIDAY NIGHT THOUGH AS
MID LEVEL FLOW REMAINS SOUTHWEST IN AN OVERRUNNING SCENARIO.
WARMING WILL CONTINUE ON FRIDAY WITH HIGH TEMPS IN THE 60S...BELOW
NORMAL BUT NOT SURPRISING WITH CLOUDY SKIES AND LIGHT RAIN CHANCES
STILL. THE WARMING WILL PERSIST THROUGH SUNDAY AS RAIN CHANCES
END. WEAK RIDGING WILL BE INDUCED BY THE CUT OFF LOW OR TROUGH
MAKING ITS WAY SLOWLY SOUTH OVER CALIFORNIA. HIGH TEMPS SUNDAY
WILL BE 75 TO 80 WITH SOME CLEARING. A MODERATE SOUTHEAST WIND
WILL ALSO RETURN. AS THE CALIFORNIA TROUGH EDGES EAST...LOW
PRESSURE WILL DEVELOP OVER THE FOUR CORNERS AREA...AND THE SOUTH
TEXAS WIND MACHINE WILL SWITCH ON MONDAY...MONDAY NIGHT...AND
TUESDAY. HIGHS IN THE 80S WILL BE REACHED MONDAY AND TUESDAY WITH
LOWS IN THE 60S MONDAY NIGHT AND TUESDAY NIGHT.

WHILE THE UPSTREAM TROUGH TAKES IT TIME EJECTING...MORE CANADIAN AIR
WILL RUSH SOUTH AND BRING A WEAK WIND SHIFT TO NORTH OR NORTHEAST ON
WEDNESDAY...WITH SLIGHTLY COOLER HIGH TEMPS FROM 75 TO 80 AND
INCREASING CLOUDINESS. THE UPSTREAM TROUGH WILL EJECT IN TIME TO
SYNCH UP WITH THE MAIN PRESSURE SURGE...WITH THE GFS FORCING A FRONT
THROUGH WEDNESDAY NIGHT AND EARLY THURSDAY MORNING. LOOKS LIKE THE
ECMWF HAS A SLIGHTLY DIFFERENT SOLUTION...WITH A FRONT DURING THE
DAY THURSDAY AND A DEEPER TRAILING TROUGH...THOUGH IT DOES ADVERTISE
SOME CLEARING LATE THURSDAY...BUT A QUICK RETURN FLOW ON FRIDAY.

FOR NOW IT LOOKS LIKE A MODEL COMPROMISE WILL YIELD A REASONABLE
SOLUTION THROUGH MID NEXT WEEK. FRIDAY NIGHT THROUGH THE WEEKEND
WILL INVOLVE A RECOVERY AS A STRONG HIGH PRESSURE SYSTEM OVER THE
PLAINS MOVES EAST AND A SHARP TROUGH DESCENDS DOWN THE EAST SIDE OF
THE EASTERN PACIFIC RIDGE. THE SLOW EJECTION OF THE TROUGH ONCE IT
SINKS OVER THE SOUTHERN CALIFORNIA AREA WILL SET UP MORE SETTLED
AND WARMER WEATHER...THOUGH PARTLY CLOUDY SKIES...DEW POINTS IN
THE 60S AND PERIODS OF STRONGER WINDS WILL KEEP THINGS OUT OF THE
CHAMBER OF COMMERCE CATEGORY.

MARINE...
NOW THROUGH FRIDAY...WINDS AND SEAS AT BUOY 42020 WERE LIGHT EARLY
THIS MORNING...ESE AT 5 KNOTS AND SEAS OF 2 FEET. FAVORABLE MARINE
CONDITIONS WILL LAST THROUGH THE MORNING HOURS AHEAD OF THE NEXT
COLD FRONT WHICH WILL MOVE INTO THE COASTAL WATERS LATER TODAY. ONCE
IT MOVES THROUGH EXPECT STRENGTHENING NORTHEASTERLY WINDS AND
BUILDING SEAS. WILL ISSUE A SMALL CRAFT ADVISORY OVER THE GULF
WATERS FROM 2 PM TO 3 AM CST. EVEN THOUGH THE SCA EXPIRES AT 3 AM
CST IT MAY NEED TO BE EXTENDED BY THE NEXT SHIFT OR REISSUED FOR
LATER FRIDAY.

FRIDAY NIGHT THROUGH MONDAY...A STRONG HIGH PRESSURE
CENTER LOCATED SOUTH OF THE GREAT LAKES WILL MOVE EAST FRIDAY
NIGHT...WITH A SHORT WAVE TROUGH DIVING SOUTH ALONG THE WEST COAST
INDUCING LOWER PRESSURE OVER THE SOUTHWEST UNITED STATES. THE
RESULT WILL BE A PRESSURE GRADIENT ACROSS THE NORTH GULF WHICH
WILL SUPPORT MODERATE TO STRONG NORTHEAST TO EAST WINDS AND A
DEFINITE SWELL COMPONENT INTO THE LOWER TEXAS COASTAL WATERS. AT
ANY RATE... BORDERLINE ADVISORY WINDS WILL BE DECREASING FRIDAY
NIGHT WHILE SEAS REMAIN ELEVATED IN SMALL CRAFT ADVISORY
TERRITORY. THE SWELL WILL LIKELY KEEP ADVISORY CONDITIONS GOING
OVER THE GULF WATERS THROUGH SUNDAY. AT THAT POINT THE HIGH
PRESSURE CENTER WILL BE OVER THE MID ATLANTIC REGION...OFFERING A
MORE SOUTHEAST WIND ORIENTATION LOCALLY BUT PERHAPS STILL SOME
LONGER PERIOD SWELL FROM THE OPEN GULF...AND PRESSURE RISES
UPSTREAM OVER THE DESERT SOUTHWEST WILL ALSO REDUCE THE TIGHTNESS
OF THE LOCAL GRADIENT.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 3 AM CST FRIDAY
     FOR GMZ150-155-170-175.

&&

$$

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

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