Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 291011
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
411 AM CST MON DEC 29 2014

.SHORT TERM /NOW THROUGH TUESDAY/...IN THE WAKE OF THE YESTERDAY`S
SHORTWAVE TROUGH...A NEARLY ZONAL FLOW ALOFT WAS NOTED EARLY THIS
MORNING. SURFACE HIGH PRESSURE HAS NOSED ITS WAY INTO DEEP SOUTH
TEXAS FROM THE MIDDLE MISSISSIPPI VALLEY. WHERE THE SKIES
CLEARED...SOME AREAS OF FOG HAVE DEVELOPED...MAINLY OVER THE
WESTERN TWO-THIRDS OF THE FORECAST AREA. OBSERVATIONAL DATA
INDICATE THAT AREAS BETWEEN ZAPATA AND HEBBRONVILLE MAY BE SEEING
LOCALLY DENSE FOG...BUT THE SEEMINGLY PATCHY NATURE OF THE DENSE
FOG PRECLUDES (AT LEAST FOR NOW) THE POSTING A DENSE FOG ADVISORY.
MEANWHILE...CLOSER TO THE COAST...LOW CLOUDS CONTINUE TO BE SEEN.

A NEARLY ZONAL FLOW ALOFT SHOULD LARGELY DOMINATE WEATHER CONDITIONS
ACROSS THE FORECAST AREA THROUGH TUESDAY...AS TROUGHINESS STARTS TO
INCREASE OVER THE WESTERN UNITED STATES.  TODAY SHOULD BE DRY...AS A
NORTHEASTERLY FLOW IN THE LOWER-LEVELS OF THE ATMOSPHERE CONTINUES
TO BE SEEN.  THE EARLY MORNING CLOUD COVER MAY THIN A BIT...BUT IS
NOT EXPECTED TO DISSIPATE COMPLETELY.

SURFACE HIGH PRESSURE SHOULD SLIDE EAST OF THE REGION TONIGHT.
EASTERLY WINDS SHOULD RETURN TO THE REGION...ALLOWING LOW-LEVEL GULF
OF MEXICO MOISTURE TO AGAIN INCREASE.  THE DEEPENING MOISTURE...
COMBINED WITH LIGHT WINDS...MAY ALLOW FOG TO AGAIN BE SEEN...WITH
THE GREATEST COVERAGE EXPECTED WEST OF THE IH-69C/US-281 CORRIDOR.
WE COULD SEE SOME PATCHY FOG CLOSER TO THE COAST...BUT ITS
DEVELOPMENT MAY BE INHIBITED BY THE PRESENCE OF LOW CLOUDS.  A FEW
STREAMER SHOWERS MAY ALSO BE SEEN.  HOWEVER...THE DEPTH/SPEED OF
BOUNDARY LAYER MOISTURE RETURN REMAINS A QUESTION IN MY MIND.  AS
SUCH...I HAVE TRENDED ANY PRECIPITATION PROBABILITIES DOWNWARD WITH
THIS FORECAST.

A TROUGH OF LOW PRESSURE IS EXPECTED TO DEVELOP NEAR THE COAST
DURING THE DAY TUESDAY.  DEEPENING LOW-LEVEL MOISTURE INTERACTING
WITH THIS FEATURE...COMBINED WITH STRENGTHENING ISENTROPIC UPGLIDE
ALONG THE 310K SURFACE...SHOULD RESULT IN RAIN COVERAGE INCREASING
OVER THE FORECAST AREA TUESDAY.  /BUTTS/

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...THE PREVIOUS FORECAST
PHILOSOPHY REMAINS ON TRACK AND THEREFORE NO SIGNIFICANT FORECAST
ADJUSTMENTS WERE MADE FOR THIS CYCLE. INVERTED SURFACE TROUGHINESS
OVER THE WESTERN GULF OF MEXICO WILL COMBINE WITH A WEST-SOUTHWEST
TO EAST-NORTHEAST MID-LEVEL FLOW OVERHEAD TO PRODUCE SCATTERED
PATCHES OF LIGHT RAIN FROM TUESDAY NIGHT THROUGH THURSDAY. THICK
CLOUD COVER AND SURFACE WINDS FROM THE NORTH TO NORTHEAST WILL
ENSURE COLD TEMPERATURES FOR THIS TIME PERIOD...PUTTING A CHILL IN
ADDITION TO THE DAMPER IN NEW YEAR/S FESTIVITIES. RAN CHANCES WILL
DROP OFF...BUT NOT DISAPPEAR ALTOGETHER...THURSDAY NIGHT THROUGH
FRIDAY AS AN AREA OF LOW PRESSURE DEVELOPS ALONG THE LOWER TEXAS
COAST AND QUICKLY EJECTS TO THE NORTH...WITH THE ASSOCIATED WARM
FRONT LEAVING WARMER TEMPERATURES WITHIN THE BRO CWFA ON FRIDAY.
500 MB LOW PRESSURE TRACKING THROUGH THE CENTRAL PLAINS WILL BRING
A COLD FRONT TO DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY SATURDAY
...WITH A QUICK SHOT OF ISOLATED PRECIPITATION. AN INFLUX OF DRIER
AIR IN THE WAKE OF THE COLD FRONT WILL FINALLY BRING DRIER WEATHER
WITH CLEARER SKIES SATURDAY NIGHT THROUGH SUNDAY...WITH DAYTIME
TEMPERATURES RECOVERING DUE TO THE SUNSHINE.
&&

.MARINE...NOW THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL DOMINATE
THE MARINE AREA THROUGH MUCH OF THE SHORT TERM...WITH RELATIVELY
LIGHT WINDS AND LOW SEAS. AN ONSHORE FLOW IS EXPECTED TO RETURN
TONIGHT AS THE HIGH SHIFTS EAST...AND WE COULD SEE A FEW STREAMER
SHOWERS OVER THE GULF OF MEXICO WATERS PRIOR TO SUNRISE
TUESDAY...WITH PRECIPITATION COVERAGE EXPECTED TO INCREASE TUESDAY
AS THE MOISTURE DEEPENS. WINDS SHOULD INCREASE AND SEAS SHOULD
BUILD TUESDAY AS THE PRESSURE GRADIENT STRENGTHENS. SMALL CRAFT
WILL LIKELY NEED TO EXERCISE CAUTION BY TUESDAY AFTERNOON AS
CONDITIONS DETERIORATE OVER THE MARINE AREA. /BUTTS/

TUESDAY NIGHT THROUGH SUNDAY...ADVERSE MARINE CONDITIONS CONTINUE
TO BE EXPECTED TUESDAY NIGHT THROUGH THURSDAY NIGHT DUE TO AN
INVERTED SURFACE TROUGH OF LOW PRESSURE ALONG THE LOWER TEXAS
COAST INTERACTING WITH HIGH PRESSURE BUILDING INTO SOUTH TEXAS.
THE FORMATION AND QUICK EXIT OF A WEAK AREA OF LOW PRESSURE OVER
THE WESTERN GULF OF MEXICO LATE THURSDAY NIGHT OR EARLY FRIDAY
MORNING WILL ACTUALLY IMPROVE WIND AND SEA CONDITIONS FOR FRIDAY...
WITH ONLY SMALL CRAFT EXERCISE CAUTION FOR A PORTION OF THE LOWER
TEXAS COASTAL WATERS. THESE SCEC CONDITIONS WILL PERSIST THROUGH
SATURDAY DUE TO THE PASSAGE OF A WEAK COLD FRONT AT THAT TIME...
WITH A POSSIBLE RETURN TO SMALL CRAFT ADVISORY WINDS AND/OR SEAS
SUNDAY AS MARINE CONDITIONS BECOME SLIGHTLY MORE ADVERSE IN THE
WAKE OF THE FRONT.
&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  59  56  69  59 /  10  10  30  50
BROWNSVILLE          62  55  71  59 /  10  10  30  50
HARLINGEN            61  53  68  57 /   0  10  30  50
MCALLEN              62  52  65  55 /   0  10  30  50
RIO GRANDE CITY      63  49  61  50 /   0  10  30  50
SOUTH PADRE ISLAND   61  59  69  61 /  10  10  30  50
&&

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

$$

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

SHORT TERM...BUTTS-53
LONG TERM...TOMASELLI-66
WX4PPT/MESO...CAMPBELL



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