[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231746
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI DEC 23 2011

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1700 UTC.

...THE ITCZ/THE MONSOON TROUGH...

THE ITCZ BEGINS INLAND OVER WRN AFRICA REACHING THE COAST OF
LIBERIA NEAR 6N10W CONTINUING ALONG 6N20W 5N30W 6N40W 4N48W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60 NM
EITHER SIDE THE AXIS BETWEEN 13W-33W.

...DISCUSSION...

GULF OF MEXICO...
A FRONTAL BOUNDARY CONTINUES TO IMPACT THE NW HALF OF THE GULF
OF MEXICO TODAY. THE NRN PORTION IS MOVING EWD AS A COLD FRONT
ACROSS GEORGIA TO THE FLORIDA PANHANDLE NEAR 30N84W TO 28N87W
WHERE IT BECOMES STATIONARY ALONG 26N93W 22N96W TO THE MEXICAN
COAST NEAR 19N96W AND CONTINUES TO THE NW INTO INLAND MEXICO.
DUE TO MOSTLY DRY AIR IN SWLY FLOW ALOFT...LITTLE SHOWER
ACTIVITY ACCOMPANIES THE FRONT BESIDES ISOLATED SHOWERS WITHIN
45 NM EITHER SIDE OF THE AXIS. HOWEVER...OVERCAST SKIES COVER
THE AREA NW OF THE FRONT. A SMALL AREA OF SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS IS S OF THE FRONT IN THE CENTRAL
GULF FROM 24N-26N BETWEEN 87W-90W. THE REMAINDER OF THE SRN HALF
OF THE BASIN IS UNDER MOSTLY CLEAR SKIES AND FAIR CONDITIONS.
DUE TO THE LACK OF UPPER LEVEL SUPPORT...THE FRONT IS EXPECTED
TO REMAIN STATIONARY THROUGH TOMORROW UNTIL A REINFORCING FRONT
MOVES OFF THE TEXAS COAST LATE SATURDAY/EARLY SUNDAY.

CARIBBEAN SEA...
WINDY CONDITIONS REMAIN ACROSS THE CARIBBEAN TODAY WITH MAINLY
NE-E TRADEWIND FLOW OF 20-25 KTS REACHING 30 KTS IN THE CENTRAL
CARIBBEAN AND GALE FORCE NEAR THE COAST OF COLOMBIA FROM 11N TO
15N BETWEEN 73W AND 78W WHICH ARE EXPECTED TO LAST ANOTHER 6
HOURS. ISOLATED SHOWERS ARE EMBEDDED WITHIN THE TRADEWIND FLOW
MAINLY BETWEEN 13N-16N WITH SOME STRONGER ACTIVITY WITH
THUNDERSTORMS ALONG THE COAST OF PANAMA...COSTA RICA...AND
NICARAGUA LIKELY DUE TO WIND SPEED CONVERGENCE ALONG THE
COASTLINE. SOME STRONG SHOWERS/THUNDERSTORMS ARE ALSO OVER
HONDURAS FROM 14N-17N BETWEEN 83W-88W. THIS ACTIVITY IS RELATED
TO UPPER LEVEL DIFFLUENCE BETWEEN AN INVERTED UPPER TROUGH OVER
THE E PACIFIC WITH AXIS ALONG 92W...AND SE-S UPPER LEVEL FLOW
ACROSS THE CARIBBEAN AROUND AN UPPER LEVEL RIDGE IN THE W ATLC.
SURFACE HIGH PRESSURE OVER THE W ATLC CONTINUES TO SUPPORT A
STRONG PRESSURE GRADIENT AND THUS HIGH WINDS...BUT IS EXPECTED
TO BEGIN TO WEAKEN IN THE NEXT 24 HOURS.

ATLANTIC OCEAN...
SURFACE RIDGING AROUND A 1029 MB HIGH NEAR 32N58W IS PROVIDING
MOSTLY FAIR WEATHER ACROSS THE WRN ATLC. THE RIDGE IS SUPPORTED
BY AN UPPER LEVEL RIDGE WITH AXIS EXTENDING FROM THE SE BAHAMAS
TO THE NE NEAR 46N47W. AN UPPER LEVEL TROUGH TO THE E ALONG 43W
CONTINUES TO SUPPORT A STATIONARY FRONTAL BOUNDARY WHICH IS NOW
N OF THE AREA. THE SRN PORTION IN WITHIN THE DISCUSSION AREA HAS
WEAKENED INTO A SURFACE TROUGH WHICH HAS BEGUN TO MOVE WWD AND
CURRENTLY LIES ALONG 31N42W TO 23N45W. SCATTERED SHOWERS ARE
MAINLY E OF THE FRONT N OF 21N BETWEEN 36W-43W UNDER THE AREA OF
STRONGEST DIFFLUENCE ALOFT. THE REMAINDER OF THE BASIN IS
INFLUENCED BY SURFACE RIDGING AROUND A 1037 MB HIGH E OF THE
AZORES ISLANDS NEAR 37N20W PROVIDING GENERALLY FAIR WEATHER
ACROSS THE ERN ATLC. ALOFT...AN UPPER LEVEL RIDGE COVERS THE FAR
E ATLC. THE UPPER TROUGH OVER THE CENTRAL ATLC IS ALSO HELPING
SUPPORT SOME UPPER LEVEL CLOUDS N OF THE ITCZ REGION.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
WALTON




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