[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 120004
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST WED JAN 11 2012

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH IS ANALYZED ACROSS AFRICA ENTERING THE E
TROPICAL ATLC NEAR 10N13W TO 9N16W. THE ITCZ CONTINUES FROM
9N16W ALONG 3N32W 1N39W ACROSS THE EQUATOR INTO SOUTH AMERICA
NEAR 50W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM
1N-3N BETWEEN 25W-33W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LOW IS MOVING NE OVER THE MOUNTAINS OF TENNESSEE WITH
THE UPPER TROUGH EXTENDING OVER THE GULF N OF 25N SUPPORTING A
COLD FRONT THAT AT 11/2100 UTC EXTENDS ACROSS THE FLORIDA
PENINSULA BETWEEN ST. AUGUSTINE AND FORT MYERS THEN THROUGH THE
YUCATAN CHANNEL INTO THE NW CARIBBEAN NEAR 22N86W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE E OF THE FRONT S OF 23N TO
OVER S FLORIDA AND W CUBA. WATER VAPOR IMAGERY INDICATES STRONG
SUBSIDENCE AND DRY STABLE AIR IS MOVING OVER THE GULF W OF THE
FRONT WITH CLEARING SKIES AND A WEAK 1013 MB HIGH OVER THE SE
GULF NEAR 23N93W. THE COLD FRONT WILL REACH THE FAR SE WATERS
EARLY TONIGHT WHERE IT WILL STALL AND WEAKEN INTO THU EVENING. A
SECOND STRONGER COLD FRONT WILL MOVE INTO THE NW GULF LATE
TONIGHT/EARLY THU AND MOVE QUICKLY ACROSS THE GULF EXITING BY
LATE FRI. HIGH PRESSURE WILL THEN BUILD ACROSS THE GULF THROUGH
SUN AND SHIFTING EASTWARD LATE SUN AND MON.

CARIBBEAN SEA...
THE FRONT OVER THE SE GULF OF MEXICO EXTENDS OVER THE NW
CARIBBEAN AT 11/2100 UTC THROUGH THE YUCATAN CHANNEL NEAR 22N86W
TO INLAND OVER THE YUCATAN PENINSULA NEAR 20N87W CONTINUING W TO
OVER S MEXICO. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE
WITHIN 45 NM E OF THE FRONT OVER THE CARIBBEAN WATERS. A BROAD
UPPER RIDGE COVERS THE CARIBBEAN WITH THE AXIS ALONG EXTENDING
FROM THE E VENEZUELA OVER THE LESSER ANTILLES INTO THE W ATLC.
WATER VAPOR IMAGERY INDICATES MOSTLY DRY STABLE AIR ACROSS THE
REGION. HOWEVER...LOW LEVEL MOISTURE IS GENERATING ISOLATED
SHOWERS WITHIN 90 NM OF LINE FROM E CUBA NEAR 20N76W TO OVER E
HONDURAS NEAR 15N84W INCLUDING JAMAICA. THE REMAINDER OF THE
CARIBBEAN IS EXPERIENCING FAIR WEATHER CONDITIONS AGAIN THIS
EVENING. THE COLD FRONT WILL WEAKEN AS IS MOVES ACROSS THE NW
CARIBBEAN TONIGHT AND SLOWLY DISSIPATE THROUGH FRI. WEAK HIGH
PRESSURE N OF THE AREA WILL SHIFT EASTWARD TONIGHT. A STRONGER
COLD FRONT WILL ENTER THE NW CARIBBEAN SAT FOLLOWED BY BUILDING
HIGH PRESSURE.

ATLANTIC OCEAN...
THE UPPER TROUGH OVER THE GULF OF MEXICO EXTENDS INTO THE W ATLC
N OF 26N W OF 76W SUPPORTING THE COLD FRONT THAT AT 11/2100 UTC
ENTERS THE ATLC OFF THE GEORGIA COAST NEAR SAVANNAH TO ACROSS
THE FLORIDA PENINSULA NEAR ST. AUGUSTINE CONTINUING INTO THE
GULF OF MEXICO AND NW CARIBBEAN. SHOWERS/THUNDERSTORMS ARE N OF
THE DISCUSSION AREA WITH ISOLATED SHOWERS WITHIN 75 NM OF LINE
FROM 29N77W TO ACROSS S FLORIDA AND THE STRAITS OF FLORIDA NEAR
FORT LAUDERDALE INCLUDING THE N BAHAMA ISLANDS. THE BROAD UPPER
RIDGE THAT COVERS THE CARIBBEAN COVERS THE W ATLC INTO THE
CENTRAL ATLC W OF 50W WITH MOSTLY FAIR CONDITIONS AND A 1018 MB
HIGH NEAR 26N66W. HOWEVER...LOW LEVEL MOISTURE TO THE W OF THE
SURFACE HIGH IS GENERATING ISOLATED SHOWERS WITHIN 90 NM OF LINE
FROM 28N70W TO ACROSS E CUBA NEAR 20N76W. A BROAD UPPER TROUGH
DIPS S INTO THE CENTRAL ATLC AND E ATLC TO 20N BETWEEN 25W-50W
SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N50W
EXTENDING ALONG 26N62W THEN NW OUT OF THE REGION NEAR 32N70W. A
SURFACE TROUGH EXTENDS FROM 29N54W TO 20N56W. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS ARE WITHIN 60 NM OF LINE FROM 27N50W TO
BEYOND 32N46W. THIS UPPER TROUGH IS ALSO SUPPORTING A STATIONARY
FRONT THAT EXTENDS TO 32N36W WHERE A SURFACE TROUGH CONTINUES
ALONG 27N36W TO 21N38W WITH SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 25N-29N BETWEEN 32W-35W. A WEAK SURFACE RIDGE
COVERS THE REMAINDER OF THE E ATLC. THE COLD FRONT MOVING OFF
THE GEORGIA COAST WILL REACH FROM 31N75W TO W CUBA THU THEN
BEGIN TO WEAKEN AS IT REACHES FROM 31N71W TO CENTRAL CUBA THU
NIGHT. A STRONGER COLD FRONT WILL MOVE OFF THE SE U.S. COAST THU
NIGHT AND REACH FROM 31N72W TO W CUBA FRI AND FROM BERMUDA TO E
CUBA SAT THEN WEAKEN AND STALL ON SUN.

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

$$
PAW





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