Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 180504 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1104 PM CST WED DEC 17 2014

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

&&

.AVIATION...LOW AND MID CLOUDS CONTINUE ACROSS DEEP SOUTH TEXAS
TONIGHT. EXPECT A MIX OF VFR/MVFR CONDITIONS FOR THE FEW HOURS
WITH WIDESPREAD MVFR CONDITIONS DEVELOPING OVERNIGHT...IFR
CONDITIONS POSSIBLE BEFORE SUNRISE THROUGH MID MORNING...AS
MOISTURE CONTINUES TO POOL ALONG AN OLD FRONT DRAPED ACROSS THE
WESTERN PORTIONS OF DEEP SOUTH TEXAS. FOG WILL ALSO BE POSSIBLE AT
ALL TAF SITES AROUND SUNRISE DUE TO LIGHT WINDS. CONDITIONS WILL
GRADUALLY IMPROVE BY MID DAY AS SOUTHEAST WINDS INCREASE.
HOWEVER...MVFR CONDITIONS MAY LINGER THROUGH THE AFTERNOON HOURS
AT MFE DUE TO THE CLOSE PROXIMITY OF THE FRONT.

&&

.PREV DISCUSSION... /ISSUED 600 PM CST WED DEC 17 2014/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE A
MIX OF LOW CLOUDS AND HIGH CLOUDS ACROSS DEEP SOUTH TEXAS THIS
EVENING. EXPECT VFR CONDITIONS TO CONTINUE ACROSS THE AREA THROUGH
LATE THIS EVENING. MVFR CONDITIONS WILL RETURN TONIGHT WITH IFR
CONDITIONS POSSIBLE LATE TONIGHT THROUGH MID MORNING AS MOISTURE
CONTINUES TO POOL ALONG AN OLD FRONT DRAPED ACROSS THE WESTERN
PORTIONS OF DEEP SOUTH TEXAS. FOG WILL ALSO BE POSSIBLE AT ALL TAF
SITES AROUND SUNRISE DUE TO LIGHT WINDS. CONDITIONS WILL GRADUALLY
IMPROVE BY MID DAY AS SOUTHEAST WINDS INCREASE. HOWEVER...MVFR
CONDITIONS MAY LINGER THROUGH THE AFTERNOON HOURS AT MFE DUE TO
THE CLOSE PROXIMITY OF THE FRONT.

PREV DISCUSSION... /ISSUED 248 PM CST WED DEC 17 2014/

SHORT TERM.../TONIGHT THROUGH THURSDAY NIGHT/...SATELLITE IMAGES AS
WELL AS SURFACE OBSERVATIONS INDICATE THE WARM FRONT IS STALLED
ACROSS THE EXTREME WESTERN PORTIONS OF THE CWA THIS AFTERNOON. THIS
IS REFLECTED IN THE TEMPERATURES IN THE 70S TO NEAR 80 ACROSS MOST
OF THE CWA EXCEPT ACROSS ZAPATA COUNTY WHERE TEMPS ARE IN THE 60S.
THE BOUNDARY IS EXPECTED TO STALL ACROSS SOUTH TEXAS TONIGHT AFTER
IT MOVES NORTHWARD ACROSS THE MIDDLE AND UPPER TEXAS COAST THIS
EVENING. AT THE UPPER LEVELS...A 500MB TROUGH WILL BE DEVELOPING
ACROSS THE SOUTHWEST UNITED STATES INTO NORTHERN MEXICO THURSDAY.
LAPSE RATES WILL BEGIN TO STEEPEN ACROSS SOUTHWEST TEXAS AS A RESULT
AND ELEVATED CONVECTION WILL DEVELOP ACROSS THE WESTERN PORTIONS OF
THE RIO GRANDE PLAINS THURS AFTERNOON ALONG THE FRONTAL BOUNDARY.
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP ACROSS THE CWA THURS AFTERNOON INTO THURS NIGHT AS
DIFFLUENCE ALOFT INCREASES AND LAPSE RATES CONTINUE TO STEEPEN AS
THE UPPER TROUGH MOVES EASTWARD ACROSS WEST TEXAS THURS NIGHT. WOULD
NOT BE SURPRISED TO SEE ISOLATED STRONG THUNDERSTORMS ACROSS THE
NORTHERN AND WESTERN PORTIONS OF THE CWA LATE THURSDAY AS LOW LEVEL
CONVERGENCE ALLOWS SOME SURFACE BASED CONVECTION TO DEVELOP IN THAT
AREA. PATCHY FOG LIKELY TO DEVELOP ACROSS THE RIO GRANDE VALLEY LATE
TONIGHT INTO THURS MORNING WITH MORE WIDESPREAD FOG POSSIBLE ACROSS
THE NORTHERN RANCH LANDS CLOSER TO THE LOCATION OF THE WARM FRONT.

LONG TERM.../FRIDAY THROUGH WEDNESDAY/...UPPER LEVEL TROUGH MOVING
ACROSS NM INTO TEXAS FRIDAY WILL PROVIDE GOOD UPPER LEVEL JET DYNAMICS
OVER THE PLAINS WHICH WILL TRANSPORT GULF MOISTURE ACROSS THE CWA
THU TO EARLY FRIDAY. THIS WILL ENHANCE ISOLATED TO SCATTERED SHOWERS
AHEAD OF THE TROUGH AXIS EARLY FRIDAY. BEHIND THE TROUGH...NEXT
COLD FRONT ARRIVES FRIDAY AFTERNOON INCREASING THE NORTH TO NORTHWEST
FLOW ACROSS THE CWA. DRY AIR WILL FILTER IN BEHIND IT PUSHING ALL
PRECIPITATION SOUTH OF THE AREA. TEMPERATURES EARLY IN THE WEEKEND
WILL BE CLOSE TO NORMAL ACROSS THE CWA WITH NORTH WINDS QUICKLY
SHIFTING NORTHEAST AND EAST AS THE UPPER LEVEL FLOW PROGRESSES
EASTWARD.

INTO SUNDAY...A SERIES OF SHORTWAVE WITHIN THE FLOW WILL MOVE ACROSS
THE AREA ENHANCING SHOWERS ACTIVITY. NEXT ELONGATED TROUGH MAKES ITS
WAY INTO NORTH CENTRAL TEXAS INCREASING THE LOW LEVEL MOISTURE OVER
THE CWA SUNDAY. THE ONSHORE FLOW WILL ENHANCE SHOWER ACTIVITY ONCE
AGAIN ALONG THE COASTAL AREAS THROUGH THE DAY WITH MOSTLY CLOUDY
CONDITIONS. THE TEMPERATURES WILL RETURN TO THE LOW 70S. STRONG UPPER
LEVEL LOW DEEPENS INTO THE GREAT LAKES. THIS WILL RESULT IN ANOTHER
ELONGATED TROUGH TO PUSH THROUGH THE CWA INTO TUESDAY. THIS WILL BRING
ANOTHER FRONT AS IT MOVES ACROSS THE AREA EARLY TUESDAY. NORTHERLY
WIND WILL INCREASE WITH HIGH PRESSURE BUILDING. HIGH WILL SHIFT
QUICKLY TO THE EAST VEERING OUR WINDS TO THE EAST TO SOUTHEAST INTO
WEDNESDAY WITH DRY CONDITIONS RETURNING ACROSS THE AREA. IF THIS
PATTERN PREVAILS WE WILL HAVE A DRY FORECAST FOR THE HOLIDAYS ACROSS
THE RGV.

MARINE...TONIGHT THROUGH THURSDAY NIGHT...SEAS WERE NEAR 3 FEET WITH
SOUTHEAST WINDS NEAR 14 KNOTS AT BUOY020 EARLY THIS AFTERNOON. LIGHT
TO MODERATE SOUTH TO SOUTHEAST WINDS WILL PREVAIL ACROSS THE COASTAL
WATERS TONIGHT INTO THURSDAY AS A WARM FRONT MOVES NORTHWARD ACROSS
THE MIDDLE AND UPPER TEXAS COAST THIS EVENING AND STALLS. WINDS WILL
INCREASE SLIGHTLY THURS NIGHT AS LOW PRESSURE ACROSS THE WESTERN
PORTIONS OF THE RGV ALLOWS THE PRESSURE GRADIENT TO INCREASE
SLIGHTLY ACROSS THE LOWER TEXAS COAST.

FRIDAY THROUGH TUESDAY NIGHT... UPPER TROUGH MOVING ACROSS
THE GULF WATERS FRIDAY WILL PUSH A FRONT ACROSS THE GULF FRIDAY
AFTERNOON. THIS WILL INCREASE WINDS AND THE POTENTIAL FOR LOWER END
SCA CONDITIONS FOR FRIDAY THROUGH FRIDAY NIGHT. SATURDAY CONDITIONS
IMPROVE WITH WINDS SHIFTING TO THE NORTHEAST. HIGH PRESSURE BUILDING
WILL SHIFT QUICKLY EAST SHIFTING WINDS TO THE EAST BY SUNDAY WILL
LOW SEAS. INTO MONDAY ANOTHER TROUGH AXIS MAKES ITS WAY ACROSS THE
GULF WATERS INCREASING THE SHOWER ACTIVITY. THE SOUTHERLY FLOW AHEAD
OF THIS SYSTEM WILL INCREASE TO SCEC CRITERIA WITH BUILDING SEAS. BY
TUESDAY THE FRONT ASSOCIATED WITH THIS SYSTEM WILL SHIFT WINDS TO THE
NORTH WITH DECENT GRADIENT WHICH WILL INCREASE WINDS TO SCA
CRITERIA. DRY AIR WILL FILTER IN BEHIND IT  LIMITING ANY ADDITIONAL
PRECIPITATION. HOWEVER...SEAS WILL BEGIN TO IMPROVE UNTIL
WEDNESDAY.

&&

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

$$

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

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