Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 252118
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
318 PM CST SUN JAN 25 2015

.SHORT TERM /NOW THROUGH MONDAY NIGHT/...
WATER VAPOR IMAGERY SHOWS A CUT-OFF LOW IN THE UPPER ATMOSPHERE
SPINNING JUST OFFSHORE THE CENTRAL COASTLINE OF BAJA CALIFORNIA.
HIGH-LEVEL MOISTURE CONTINUES TO FLOW INTO THE REGION THIS AFTERNOON
(LARGELY THANKS TO THIS SYSTEM)...PROVIDING A BLANKET OF CLOUD COVER
FOR MUCH OF THE AREA.

ANY CLOUD COVER OVER THE REGION TONIGHT SHOULD START TO DIMINISH...
AS THE CUT-OFF LOW STARTS MOVING NORTHWARD AND A WEAK TROUGH OF LOW
PRESSURE MOVES THROUGH THE AREA.  RIDGING...BOTH AT THE SURFACE AND
ALOFT...IS THEN EXPECTED TO ASSERT ITSELF FOR THE REMAINDER OF THE
SHORT TERM PORTION OF THE FORECAST.  ONLY A WIND SHIFT IS EXPECTED
AS THE TROUGH MOVES THROUGH...WITH WINDS SHIFTING TO A MORE
NORTHERLY DIRECTION BY MONDAY.  OVERALL THOUGH...WIND SPEEDS ARE
EXPECTED TO REMAIN BELOW 10 MPH THROUGH MONDAY NIGHT.

AFTER OVERNIGHT LOWS ONCE AGAIN IN THE 40S ACROSS OUR CORNER OF THE
WORLD...HIGHS MONDAY SHOULD BE RATHER TYPICAL FOR DEEP SOUTH TEXAS.
EXPECT SLIGHTLY WARMER TEMPERATURES MONDAY NIGHT THANKS TO INCREASED
RIDGING ALOFT.  /BUTTS/

.LONG TERM /TUESDAY THROUGH SUNDAY/...500 MB RIDGING WILL PREVAIL
OVER TX AND THE WESTERN GULF FROM TUESDAY THROUGH THURS AS STRONG
TROFFING DIGS OVER THE EAST AND WEST COASTS. A SHORT WAVE EMBEDDED
IN THE BROADER 500 MB FLOW PATTERN OVER THE EASTERN STATES WILL
PULL A WEAK COLD FRONT THROUGH THE AREA THURS NIGHT INTO FRI
MORNING. OVER THE WEST COAST...A 500 MB TROUGH THEN DIGS SLOWLY
EAST EVENTUALLY CUTTING OFF OVER THE DESERT SW THIS WEEKEND. THE
PERSISTENT 500 MB TROFFING OVER THE EASTERN STATES WILL THEN PUSH
A STRONGER COLD THROUGH THE RGV ON SUN. AS THE 500 MB CLOSED LOW
OVER THE DESERT SW SPINS SLOWLY EASTWARDS PRETTY GOOD MOISTURE
ADVECTION WILL OCCUR OVER THE SOUTH CENTRAL PLAINS STATES AHEAD OF
THE STRONGER WEEKEND FRONT WHICH WILL ALLOW POPS TO START
INCREASING SAT AND SUN. THE INCREASING CLD COVER...POPS AND BETTER
CAA WILL START DRIVING TEMPS DOWN TO NEAR OR SLIGHTLY BELOW CLIMO
AROUND SUN.

THE ECMWF AND GFS MODELS 500 MB FIELDS ARE IN A LITTLE BETTER
AGREEMENT THROUGH SUN. THE BIGGEST DIFFERENCES REMAIN WITH THE
ANTICIPATED PLACEMENT OF THE 500 MB LOW OVER THE DESERT SW. THE
GFS IS A LITTLE FURTHER SOUTH THAN THE ECMWF FOR SAT AND SUN WHICH
RESULTS IN THE GFS COMING IN MUCH WETTER VERSUS THE ECWMF. ANOTHER
CONTRIBUTING FACTOR TO THE HIGHER GFS POPS IS THAT IT TRIES TO
SPIN UP A STRONGER COASTAL SURFACE TROUGH NEAR THE TX COASTLINE
FOR THIS WEEKEND VERSUS THE ECMWF. WOULD LIKE TO SEE SOME BETTER
CONSISTENCY WITH THE GFS CONCERNING THE FORMATION OF THIS STRONGER
SURFACE LOW/TROUGH BEFORE JUMPING ON THE WETTER SOLUTION.

SO WILL GO WITH A BLEND OF THE ECMWF AND GFS POPS LATE IN THE
FORECAST PERIOD. WILL LEAN CLOSER TO THE ECMWF TEMPS THROUGH DAY
7. OVERALL CONFIDENCE IN THE LONGER RANGE FORECAST WORDING IS
STILL ABOVE AVERAGE TODAY DESPITE THE MODEL DIFFERENCES SHOWING UP
FOR THIS WEEKEND.

&&

.MARINE...

NOW THROUGH MONDAY NIGHT...
AN SLIGHTLY INCREASED PRESSURE GRADIENT BEHIND A SOUTHWARD-MOVING
SURFACE TROUGH OF LOW PRESSURE MAY RESULT IN A BRIEF INCREASE IN
WIND SPEEDS BEYOND 20 NMI. FROM THE COAST TONIGHT.  A FEW GUSTS IN
EXCESS OF SMALL CRAFT EXERCISE CAUTION CRITERIA MAY BE SEEN...BUT IN
GENERAL...WIND SPEEDS SHOULD REMAIN BELOW 15 KTS.  THE PRESSURE
GRADIENT SHOULD RELAX A BIT MONDAY AND MONDAY NIGHT AS RIDGING
REBUILDS OVER THE REGION.  SIGNIFICANT WAVE HEIGHTS SHOULD AVERAGE
AROUND 2 FT.... ALTHOUGH HEIGHTS AROUND 4 FT. MAY BEEN OVER THE FAR
OFFSHORE WATERS TONIGHT BEHIND THE SURFACE TROUGH.  WAVE PERIODS
THROUGH MONDAY NIGHT SHOULD HOVER BETWEEN 4 AND 5 SECONDS.  /BUTTS/

TUESDAY THROUGH FRIDAY...WEAK TO MODERATE MID LEVEL AND SURFACE
RIDGING WILL REMAIN IN CONTROL OVER THE TX COASTLINE FOR MUCH OF
THE UPCOMING CWF PERIOD. HOWEVER THE WEAK COLD FRONT PUSHING THROUGH
THE LOWER TX BAY AND GULF WATERS ON THURS WILL RAISE UP THE WINDS
AND SEAS A BIT FOR THURS AND FRI. HOWEVER NO SCA CONDITIONS
EXPECTED THROUGH FRI.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  48  68  49  72 /   0   0   0   0
BROWNSVILLE          47  70  48  75 /   0   0   0   0
HARLINGEN            46  71  47  76 /   0   0   0   0
MCALLEN              47  72  49  78 /   0   0   0   0
RIO GRANDE CITY      45  73  49  78 /   0   0   0   0
SOUTH PADRE ISLAND   52  67  52  69 /   0   0   0   0

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&

$$

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

SHORT TERM...53
LONG TERM...60
GRAPHICAST/UPPER AIR...58




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