[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011741
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU DEC 01 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
1735 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH REMAINS INLAND ACROSS AFRICA. THE ITCZ
EXTENDS ALONG THE COASTS OF GHANA AND COTE D'IVOIRE...ENTERING
THE E TROPICAL ATLC ACROSS LIBERIA NEAR 6N10W CONTINUING
WESTWARD ALONG 7N20W 8N40W 7N50W ENDING AT 9N55W. CLUSTERS OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 100-150
NM ON EITHER SIDE OF THE ITCZ.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER TROUGH IS DIGGING S ACROSS THE FAR ERN GULF AND FLORIDA
PENINSULA E OF 84W. BEHIND THIS UPPER LEVEL FEATURE...ZONAL
WESTERLY FLOW ALOFT PREVAILS ACROSS THE REMAINDER OF THE AREA.
THIS DRY STABLE AIRMASS COMBINED WITH STRONG SUBSIDENCE
CONTINUES TO DOMINATE THE GULF WITH A FEW AREAS OF STRATOCUMULUS
CLOUDS OVER ERN HALF OF THE GULF AND MOSTLY CLEAR SKIES OVER THE
REMAINDER OF THE GULF. FAIR WEATHER CONDITIONS WILL CONTINUE
THROUGH SATURDAY. A COLD FRONT WILL MOVE INTO THE NW GULF LATE
SUNDAY WITH GALE CONDITIONS EXPECTED IN THE WRN BAY OF CAMPECHE
W OF THE FRONT LATE MONDAY.

CARIBBEAN SEA...
A WEAK STATIONARY FRONT IS ANALYZED ACROSS ERN CUBA INTO THE
CARIBBEAN AS A SHEAR LINE AXIS EXTENDING FROM NEAR 20N77W TO THE
SW CARIBBEAN NEAR 11N81W. ISOLATED SHOWERS ARE POSSIBLE OVER THE
NW CARIBBEAN W OF THE SHEAR LINE...ESPECIALLY WITHIN 60 NM OFF
THE COAST OF WRN PANAMA AND COSTA RICA. WATER VAPOR IMAGERY
SHOWS AN UPPER LEVEL ANTICYCLONIC CIRCULATION OVER CENTRAL
AMERICA WHILE A NARROW UPPER TROUGH MOVING ACROSS THE FAR ERN
CARIBBEAN. THESE TWO FEATURES ARE PROVIDING DRY STABLE AIR ALOFT
AND STRONG SUBSIDENCE TO ALMOST THE ENTIRE DISCUSSION AREA. THE
MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA TO
ACROSS COSTA RICA ALONG 10N...AND IS POSSIBLY GENERATING
ISOLATED SHOWERS WITHIN 75 NM ALONG THE COAST OF COLOMBIA. A
SLOW MOVING SURFACE TROUGH IS JUST A FEW MILES E OF THE LESSER
ANTILLES GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
E OF 65W S OF 15N. THE SHEAR LINE WILL DISSIPATE LATE TONIGHT
WHILE THE SURFACE TROUGH LINGERS OVER THE LESSER ANTILLES
THROUGH MONDAY.

ATLANTIC OCEAN...
AN UPPER TROUGH IS MOVING OFF THE ERN CONUS SEABOARD INTO THE W
ATLC N OF 24N W OF 72W WITH A RE-INFORCING SHOT OF COLD AIR OVER
THIS AREA. A WEAKENING STATIONARY FRONT REMAINS UNSUPPORTED OVER
THE W ATLC GENERATING ISOLATED SHOWERS WITHIN 20 NM ON EITHER
SIDE OF THE FRONT ANALYZED FROM 29N70W CONTINUING SW ACROSS THE
S BAHAMA ISLANDS NEAR 23N74W INTO ERN CUBA ALONG 20N77W. A
NARROWING UPPER LEVEL TROUGH IS IN THE W/CENTRAL ATLC SUPPORTS A
WEAK COLD FRONT EXTENDING FROM A 1006 MB SURFACE LOW NEAR 36N61W
TO 30N60W TO 22N61W. NO CONVECTION IS ASSOCIATED WITH THIS
FRONT. A SURFACE TROUGH IS JUST E OF THE LESSER ANTILLES
ANALYZED FROM 19N58W TO W OF TRINIDAD AND TOBAGO NEAR 10N62W
WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 120/150
NM EITHER SIDE OF THE TROUGH AXIS. AN UPPER TROUGH COVERS THE
ERN ATLC N OF 25N E OF 40W SUPPORTING A COLD FRONT THAT ENTERS
THE REGION NEAR 32N22W TO 27N30W. SCATTERED SHOWERS ARE WITHIN
30 NM SE OF THE FRONT. THE REMAINDER OF THE ATLC IS DOMINATED BY
A NARROW HIGH AMPLITUDE UPPER RIDGE CENTERED OVER 40N36W.

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

$$

GARCIA




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