Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 190006 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
606 PM CST THU DEC 18 2014

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

&&

.AVIATION...A WEAK FRONTAL BOUNDARY EXTENDING FROM HRL NORTHWARD
NEAR TO BKS. LATEST OBSERVATIONS INDICATE THAT A MIX OF IFR/MVFR
CONDITIONS CONTINUE ALONG AND WEST OF THE BOUNDARY WITH VFR
EAST. LOW CEILINGS/VIS ALONG WITH PATCHY FOG IS EXPECTED TO
CONTINUE ACROSS DEEP SOUTH TEXAS TONIGHT INTO FRIDAY MORNING AS
MOIST SOUTHEAST FLOW PERSISTS. A COLD FRONT WILL MOVE ACROSS THE
AREA FRIDAY AFTERNOON WITH WINDS SHIFTING TO THE NORTHWEST IN THE
AFTERNOON. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
POSSIBLE AHEAD OF THE FRONT BUT CONFIDENCE IS NOT HIGH ENOUGH TO
MENTION MORE THAN VCSH AT THIS TIME. CEILINGS WILL GRADUALLY
IMPROVE FRIDAY AFTERNOON AS DRIER AIR FILTERS INTO THE RIO GRANDE
VALLEY.

&&

.PREV DISCUSSION... /ISSUED 245 PM CST THU DEC 18 2014/

SHORT TERM /NOW THROUGH FRIDAY NIGHT/...LATEST OBSERVATION AND SAT
IMAGERY SHOW THE STATIONARY FRONT SOUTH OF ZAPATA INTO HEBBRONVILLE
AND NORTH OF FALFURRIAS EXTENDING NORTHEAST ALONG THE TEXAS COASTAL
WATERS. THIS FRONT HAS BEEN FLUCTUATING NORTH AND SOUTH ALL MORNING
AND HAS DEVELOP A SFC BOUNDARY CLOSE TO MFE AREA. THIS HAS ALLOW FOR
A BAND OF LIGHT BRIEF SHOWERS TO DEVELOP OVER THE RIO GRANDE VALLEY
AND COASTAL COUNTIES EAST OF HWY 281 TODAY. THE SHOWER ACTIVITY WILL
CONTINUE THROUGH THE AFTERNOON AS THE UPPER LEVEL TROUGH...CURRENTLY
OVER NEVADA HEADS EAST...AND MAKES ITS WAY ACROSS WEST AND SOUTH TX
FRIDAY.

AHEAD OF THIS TROUGH...THE SURFACE BOUNDARY WILL BE LIFT NORTHWARD
RETURNING A SOUTH TO SOUTHEAST FLOW AT THE SURFACE PULLING ABUNDANT
LOW AND MID LEVEL MOISTURE NORTH. AS THE TROUGH MOVES EAST A DECENT
DIFFLUENCE AREA ALOFT WILL PROVIDE UPPER LEVEL SUPPORT FOR ISOLATED
THUNDERSTORMS POSSIBLE. AREAS MOST LIKELY TO SEE THE HIGHER CHANCE
OF AN ISOLATED THUNDERSTORM WILL REMAIN FOR THE NORTHERN COUNTIES
WHERE THE BETTER LIFT WILL BE. CAN NOT RULED OUT AN ISOLATED CASE OF
THUNDERSTORM WITH THE POTENTIAL OF PRODUCING HAIL AND MODERATE TO
HEAVY RAINFALL. THE BEST POTENTIAL WILL BE OVERNIGHT AS THE TROUGH
MOVES CLOSER TO OUR CWA. AS THE CLOUD DECK REMAINS THROUGH THE NIGHT
WITH THE SOUTHERLY WINDS AND 850 TEMPS ON THE INCREASE...EXPECT THE
TEMPS OVERNIGHT TO REMAIN IN THE MID TO UPPER 60S WHILE COOLER OVER
ZAPATA AND HEBBRONVILLE.

AS THE TROUGH EXITS AND MOVES EASTWARD DRY AIR WILL FILTER IN BEHIND
ASSOCIATED WITH THE NEXT FRONT. THIS FRONT WILL ONLY BRING TEMPS
CLOSE TO NORMAL FOR THIS TIME OF YEAR. MAIN SHIFT IN THE WINDS TO THE
NORTH TO NORTHWEST WILL BE AROUND NOON TIME FRIDAY WITH THE SHOWER
ACTIVITY GRADUALLY SUBSIDING AND SHIFTING TOWARDS THE COASTAL WATERS
BY FRIDAY AFTERNOON. HIGH TEMPERATURES FRIDAY WILL BE IN THE MID 70S
BUT THE LOWS OVERNIGHT WILL LOWER INTO THE UPPER 40S OVER THE NORTHERN
COUNTIES AND MID 50S ACROSS THE RIO GRANDE VALLEY.

LONG TERM /SATURDAY THROUGH THURSDAY/...SURFACE HIGH PRESSURE
WILL CONTINUE TO BUILD INTO SOUTH TEXAS IN THE WAKE OF THE COLD
FRONT THAT IS EXPECTED TO MOVE THROUGH THE RIO GRANDE VALLEY FRI
AFTERNOON. MEANWHILE...A 500MB TROUGH WILL DEVELOP ACROSS THE
WEST TEXAS INTO NORTHERN MEXICO SATURDAY INTO SUNDAY. THIS WILL
ALLOW A COASTAL LOW/TROUGH TO DEVELOP OFFSHORE THE NORTHEAST
MEXICAN COAST SAT NIGHT INTO SUNDAY. OVERRUNNING CONDITIONS WITH
LIGHT RAIN WILL LIKELY DEVELOP ACROSS THE EASTERN PORTIONS OF THE
CWA SAT NIGHT INTO SUNDAY BEFORE THE COASTAL LOW MOVES NORTHEAST
SUN NIGHT. THIS WILL BRING DRIER AIR INTO THE CWA SUNDAY INTO
MONDAY. SOUTHWEST FLOW MONDAY SHOULD BRING WARMER TEMPERATURES
THAN HAVE BEEN FORECAST THE PAST COUPLE OF DAYS. AS THE UPPER
LEVEL TROUGH ACROSS THE CENTRAL UNITED STATES MONDAY MOVES
EASTWARD TUESDAY...A COLD FRONT WILL MOVE THROUGH THE AREA TUESDAY
AFTERNOON. SURFACE HIGH PRESSURE WILL SETTLE ACROSS DEEP SOUTH
TEXAS WEDNESDAY BEFORE SHIFTING EASTWARD BEFORE MOVING EASTWARD
THURSDAY PROVIDING A FAIRLY WARM AND BREEZY CONDITIONS ON
CHRISTMAS DAY.

MARINE...
NOW THROUGH FRIDAY NIGHT...AN UPPER TROUGH OVER WESTERN
PORTION OF THE STATE WILL MOVE EAST CLOSER INTO THE CWA TONIGHT INTO
FRIDAY. THIS SYSTEM WILL ENHANCE SHOWERS AND ISOLATED THUNDERSTORMS
TONIGHT AND FRIDAY. CURRENTLY...STATIONARY FRONT WILL CONTINUE TO
LIFT NORTH KEEPING A SOUTHERLY FLOW OVER THE GULF WATERS WITH
ISOLATED SHOWERS BECOMING MORE SCATTERED AS WE GET CLOSER INTO THE
EVENING HOURS WITH LOW SEAS. BY TONIGHT...THE MAIN CONVECTION WILL
REMAIN INLAND BUT BY EARLY SUNRISE A CONVERGENCE ZONE WILL BE IN THE
GULF WATERS ENHANCING THE CONVECTION ACTIVITY. SOME OF THE STORMS
COULD PRODUCE HAIL ESPECIALLY OVER THE NORTHERN MARINE ZONES. INTO
FRIDAY...THE TROUGH MOVES EAST AND SO DOES THE CONVECTION BUT A
FRONT ASSOCIATED WITH THIS SYSTEM WILL MAKE ITS WAY ACROSS THE GULF
WATERS INCREASING THE NORTHERLY WINDS AND BUILDING SEAS FRIDAY
AFTERNOON. EXPECT SCEC POTENTIAL EARLY FRIDAY BECOMING SCA BY FRIDAY
NIGHT TILL MIDNIGHT AND POSSIBLY CONTINUING INTO THE LONG TERM.

SATURDAY THROUGH TUESDAY...MODERATE TO STRONG NORTH WINDS WILL
PREVAIL ACROSS THE COASTAL WATERS SATURDAY AS HIGH PRESSURE BUILDS
IN THE WAKE OF THE COLD FRONT MOVING OFFSHORE THE LOWER TEXAS
COAST FRI NIGHT. THE PRESSURE GRADIENT WILL REMAIN RELATIVELY
STRONG ACROSS THE WESTERN GULF OF MEXICO SUNDAY AS A COASTAL
LOW/TROUGH IS EXPECTED TO DEVELOP OFFSHORE THE NORTHEAST MEXICAN
COAST SAT NIGHT INTO SUNDAY. MODERATE NORTHEAST WINDS SUNDAY WILL
BECOME LIGHT AND VARIABLE EARLY MONDAY BEFORE VEERING TO THE
SOUTH MON NIGHT AND SOUTHWEST TUES MORNING AHEAD OF THE NEXT COLD FRONT
MOVING OFFSHORE THE LOWER TX COAST TUES AFTERNOON. WINDS WILL
SHIFT TO THE NORTHWEST AND INCREASE TUESDAY IN THE WAKE OF THE
FRONT. SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR THE
OFFSHORE WATERS SATURDAY AND SUNDAY AS WELL AS TUESDAY.

&&

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

$$

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