Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 240534 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1234 AM CDT FRI OCT 24 2014

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

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE
CLEAR SKIES ACROSS THE CWA LATE TONIGHT. EXPECT MVFR CONDITIONS TO
DEVELOP FRI MORNING AS CLEAR SKIES AND LIGHT WINDS ALLOW PATCHY
FOG TO DEVELOP ACROSS PORTIONS OF THE RIO GRANDE VALLEY.
OTHERWISE...VFR CONDITIONS WILL PREVAIL EARLY FRI MORNING THROUGH
FRI AFTERNOON AS 500MB RIDGE ACROSS SOUTHWEST UNITED STATES AND
NORTHERN MEXICO PROVIDES SUBSIDENCE ACROSS THE CWA.
&&

.PREV DISCUSSION... /ISSUED 613 PM CDT THU OCT 23 2014/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...FAVORABLE FLYING CONDITIONS LOOK LIKELY THROUGH THE
NEXT 24 HOURS AS STRONG HIGH PRESSURE MOVES IN FROM THE WEST AMID
MODEST NORTHEAST WINDS. PATCHY GROUND FOG WILL BE POSSIBLE AROUND
DAYBREAK BUT IS NOT EXPECTED TO PRODUCE OPERATIONALLY SIGNIFICANT
RESTRICTIONS. /68-JGG/

PREV DISCUSSION... /ISSUED 318 PM CDT THU OCT 23 2014/

SHORT TERM /NOW THROUGH FRIDAY NIGHT/...WEAK SHORTWAVE TROUGH IS
MOVING ACROSS CENTRAL AND SOUTHERN TEXAS WITH ENOUGH SYNOPTIC LIFT
TO SPARK A FEW SPRINKLES ACROSS THE NORTHERN RANCHLANDS WHICH ARE
MOVING SOUTHEAST. NOT THINKING THESE ARE GOING TO AMOUNT TO MUCH SO
WILL LEAVE SILENT 10S IN FOR THIS AFTERNOON AND EVENING UNTIL THE
TROUGH SWINGS THROUGH.

DRY AIR IS ON THE WAY WITH BRO PWAT OF 1.57 INCHES AND CRP PWAT OF
1.3 INCHES. FURTHER NORTH LIX PWAT WAS 0.36 THIS MORNING. BEHIND THE
TROUGH UPPER LEVEL HIGH PRESSURE WILL BUILD IN WITH SUBSIDENCE ALOFT
AND DRY AIR FILTERING IN ON NORTHERLY UPPER FLOW. 700-300MB RH FALLS
BELOW 10 PERCENT AND THE LOW LEVELS BEGIN TO DRY OUT AS WELL. PWATS
WILL FALL BELOW AN INCH BY FRIDAY NIGHT.

AFTER THIS EVENING...POPS WILL BE VIRTUALLY NIL THROUGH THE SHORT
TERM. SFC HIGH PRESSURE WILL BUILD SOUTHWESTWARD ACROSS LOUISIANA
AND INTO UPPER TEXAS COAST. WINDS WILL CONTINUE FROM THE NORTHEAST
AND STAY ON THE LIGHT SIDE. WITH THE LIGHT WINDS SOME SHALLOW PATCHY
FOG MAY BE POSSIBLE ACROSS THE RANCHLANDS TONIGHT AND ONCE AGAIN
FRIDAY NIGHT.

AS FAR AS TEMPERATURES GO WENT WITH CONSENSUS BETWEEN MET AND MAV
WITH HIGH PRESSURE AND DRY AIR WORKING IN. THIS HAD LITTLE EFFECT ON
THE GOING FORECAST...PERHAPS WARMING THE VALLEY UP A DEGREE OR SO.
HIGHS WILL BE IN THE MIDDLE TO UPPER 80S AND LOW WILL BE IN THE
LOWER TO MIDDLE 60S.

LONG TERM /SATURDAY THROUGH THURSDAY/...500 MB RIDGING WILL
DOMINATE MUCH OF THE SOUTH CENTRAL PLAINS STATES AND NORTHERN
MEXICO THROUGH MUCH OF THE EXTENDED RANGE FORECAST PERIOD. HOWEVER
THE RIDGE AXIS WILL START TO DEGRADE NEXT WEEK AS A LARGE TROUGH
AXIS DIGS ACROSS MUCH OF THE LOWER 48 STATES. AS THIS TROUGH AXIS
DIGS INTO THE MIDWESTERN STATES A COLD FRONT WILL PUSH INTO THE
CENTRAL PORTIONS OF TX WED AND THURS. SOME DECENT MOISTURE
ADVECTION OCCURS OVER THE STATE AHEAD OF THIS FRONT AND OVER THE
CENTRAL AND WESTERN GULF OF MEX.

BOTH THE ECMWF AND THE GFS MODELS APPEAR TO HAVE A DECENT HANDLE
ON THE PROGRESS OF THE 500 MB TROUGH DIGGING INTO THE CENTRAL
PLAINS STATES. THE ECMWF APPEARS TO HAVE A LITTLE QUICKER MOVEMENT
OF THE MID LEVEL TROUGH VERSUS THE GFS. ACCORDINGLY THE ECMWF
SHOWS A LITTLE BETTER MOISTURE ADVECTION OVER DEEP SOUTH TX
TOWARDS THE END OF THE FORECAST PERIOD. NEITHER MODEL SHOWS MUCH
POTENTIAL FOR A STRONG FROPA ACROSS THE LOWER RGV WITH THIS TROUGH
AXIS WITH BOTH MODELS STALLING THE FRONT OUT TO OUR NORTH. THIS
SOLUTION LOOKS REASONABLE CONSIDERING THE AGREEMENT INDICATED BY
BOTH LONGER RANGE MODELS.

EXPECT OVERALL TEMPS TO REMAIN AT OR ABOVE CLIMO THROUGH DAY 7 DUE
TO THE IMPACT OF THE MID LEVEL RIDGING AND LIMITED MOISTURE
VALUES. WILL GO WITH A GENERAL BLEND OF THE ECMWF AND GFS TEMPS
FOR BOTH TEMPS AND POPS.

MARINE...NOW THROUGH FRIDAY NIGHT...STILL RECEIVING ELEVATED SEAS
FROM WHATS LEFT OF THE REMNANTS OF TROPICAL DEPRESSION NINE BUT AN
OVERALL DECREASE IN WAVE HEIGHTS IS EXPECTED IN THE SHORT TERM. HIGH
PRESSURE WILL BUILD IN WITH LIGHT TO MODERATE NORTHEAST SFC FLOW
CONTINUING. WAVE HEIGHTS WILL FALL FROM 4.5 FEET CURRENTLY AT BUOY
42020 TO CLOSER TO 3 FEET BY FRIDAY NIGHT.

SATURDAY THROUGH TUESDAY...THE DEVELOPMENT OF A STRONGER SURFACE
LOW OVER THE CENTRAL PLAINS STATES EARLY NEXT WEEK WILL BUILD THE
WINDS AND SEAS CLOSE TO SCA LEVELS ON MONDAY AND TUESDAY.
OTHERWISE A WEAK PGF WILL MAINTAIN FAIRLY LOW WINDS AND SEAS
SATURDAY AND SUNDAY.
&&

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

$$

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