000
FXUS64 KBRO 221951
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
151 PM CST SUN NOV 22 2009

.DISCUSSION...THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM IS
THE EXPECTED COLD FRONT THAT WILL PASS THRU DEEP SOUTH TX ON
TUESDAY. PRIOR TO THAT...HIGH PRESSURE WILL BEGIN TO SLIDE EWD
LATER TNGT THRU MON. RETURN FLOW ON THE BACKSIDE OF THE HIGH WILL
BRING WINDS BACK AROUND TO THE SOUTHEAST AND REMAIN LIGHT TO
MODERATE TNGT THRU MON. EXPECTING ANOTHER ROUND OF SOME WIDESPREAD
FOG TO DEVELOP AFTER MIDNIGHT...MUCH LIKE WHAT TOOK PLACE EARLY
THIS MRNG. TEMPERATURES WILL BEGIN TO MODERATE UNDER THE SE SFC
FLOW AS MOISTURE RETURNS FROM THE GULF. CLD COVER WILL INCREASE
WITH TIME THRU MON WITH A SLIGHT CHC FOR PCPN DEVELOPING NEAR
COASTAL LOCALES BY THE END OF THE DAY MON. THAT CHC WILL INCREASE
FURTHER THRU MON NGT AND INTO TUE AS THE COLD FRONT WILL BEGIN
IT/S TRACK THRU DEEP SOUTH TX. MDLS PROG THE FRONT TO PASS THRU
FROM AROUND MIDDAY IN THE NORTH CWA TO LATE AFTN/EARLY EVE ACROSS
OUR SOUTHERN ZONES. HIGH PRESSURE IS ANTICIPATED TO GRADUALLY
BUILD IN BEHIND THIS SYSTEM ON WED INTO THU. CLDS SHUD GRADUALLY
DECREASE WITH TIME AS THE FRONT MOVES FARTHER SOUTH AND THE HIGH
BECOMES MORE OF AN INFLUENCE. ATTM...DRY CONDITIONS ARE
ANTICIPATED TO PREVAIL THRU THANKSGIVING DAY AND INTO THE END OF
THE WEEK. MDLS LINGER MOISTURE TO OUR SOUTH THRU THE END OF THE
WEEK ACROSS MEXICO...BUT HAVE INDICATED THIS WITH EXTRA CLD COVER
THU INTO FRI AT THIS POINT. TEMPERATURE WILL REMAIN SEASONAL FOR
THIS TIME OF YEAR WITH A FEW COOL MRNGS POSSIBLE BEHIND THE COLD
FRONT BEGINNING WED MRNG.

&&

.AVIATION...THE MORNING CLD COVER AND FOG IS CURRENTLY CONCENTRATED
OVER THE UPPER PORTIONS OF THE LOWER RIO GRANDE VALLEY MAINLY WEST
OF HIGHWAY 281. THE DAYTIME HEATING WILL STEADILY MIX OUT THE
SURFACE LAYER DIMINISHING THE FOG AND LOW STRATUS DECKS. EXPECT VFR
CONDITIONS TO PREVAIL INTO THE AFTERNOON AND EARLY EVENING HOURS.
HOWEVER LATE NIGHT AND EARLY MORNING FOG WILL BE A POTENTIAL PROBLEM
ONCE AGAIN AFTER 06Z TONIGHT POSSIBLY REDUCING VSBYS AND CEILINGS
DOWN TO MVFR/IFR LEVELS BEFORE SUNRISE TOMORROW ESPECIALLY FOR THE
HRL AND MFE AREAS. WILL REFLECT THIS EXPECTED TREND IN THE 18Z TAF
ISSUANCE.

&&

.MARINE...A LIGHT EAST TO NORTHEAST SURFACE FLOW CURRENTLY PREVAILS
OVER THE LOWER TX BAY AND GULF WATERS THIS AFTERNOON WITH BUOY020
REPORTING SWELLS NEAR 3 FEET. THE MARINE WINDS WILL CONTINUE
SHIFTING AROUND TO A MORE ONSHORE FLOW LATER TODAY AND TONIGHT BUT
WILL REMAIN LOW. THIS SHOULD LIMIT THE SWELLS TO AROUND 3 FT IN THE
SHORT TERM. FAIRLY BENIGN MARINE CONDITIONS WILL PREVAIL ACROSS THE
LOWER TX COASTAL AREAS THROUGH MONDAY NIGHT INTO EARLY TUES WITH A
LIGHT ONSHORE SURFACE FLOW PERSISTING DUE TO THE PRESENCE OF THE
SURFACE RIDGE OVER THE WESTERN GULF OF MEXICO. THE NEXT ITEM OF
CONCERN WILL BE THE NEXT COLD FRONTAL PASSAGE EXPECTED LATE TUES.
THIS NEXT FROPA OCCURRING LATER ON TUES WILL YIELD A MUCH TIGHTENED
PGF OVER THE REGION TUES NIGHT INTO WED LIKELY REQUIRING SMALL CRAFT
ADVISORIES FROM TUES AFTERNOON INTO WED FOR BOTH THE BAY AND GULF
WATERS. THE PGF WILL SLACKEN STEADILY DURING THE LATTER HALF OF THIS
UPCOMING WEEK WITH A CALMER N-NE WIND FLOW EXPECTED FROM THURS INTO
FRI.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  63  80  68  78 /   0  10  30  60
BROWNSVILLE          60  80  67  78 /   0  10  30  60
HARLINGEN            60  81  66  77 /   0  10  30  60
MCALLEN              61  81  67  77 /   0  10  20  60
RIO GRANDE CITY      60  81  63  75 /   0  10  20  60
SOUTH PADRE ISLAND   63  79  65  77 /   0  10  30  50

&&

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

$$

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

SYNOPTIC/GRIDS...VIPOND-57
MARINE/AVIATION...SPEECE-60
MESO/GRAPHICAST...MARTINEZ