[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 021148
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST FRI DEC 02 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 12N16W TO 9N19W. THE ITCZ EXTENDS FROM 9N19W ALONG
4N27W 9N41W TO SOUTH AMERICA NEAR 5N56W. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 4N-9N BETWEEN
17W-26W AND FROM 5N-13N BETWEEN 32W-47W.

...DISCUSSION...

GULF OF MEXICO...
NEAR ZONAL WESTERLY FLOW ALOFT PREVAILS ACROSS THE ENTIRE GULF.
DRY STABLE AIR AND STRONG SUBSIDENCE CONTINUES TO DOMINATE THE
GULF E OF 94W. ISOLATED SHOWERS ARE INLAND AND WITHIN 45 NM
ALONG THE COAST OF CUBA BETWEEN 81W-83W. SCATTERED COLD AIR
CLOUDS DOT THE GULF BUT MOSTLY FAIR WEATHER PREVAILS THIS
MORNING. A SURFACE RIDGE COVERS THE GULF AND THE SE CONUS
ANCHORED BY A 1029 MB HIGH OVER E MISSISSIPPI AND A SECOND 1029
MB HIGH OVER SOUTH CAROLINA. SURFACE RIDGE WILL SHIFT E THROUGH
SUN IN ADVANCE OF A COLD FRONT EXPECTED TO MOVE INTO THE NW GULF
SUN EVENING. THE FRONT WILL REACH FROM THE FLORIDA PANHANDLE TO
THE BAY OF CAMPECHE TUE.

CARIBBEAN SEA...
THE SHEAR LINE THAT WAS OVER THE W CARIBBEAN HAS DISSIPATED. A
BROAD UPPER RIDGE DOMINATES THE CARIBBEAN W OF A NARROW UPPER
TROUGH THAT EXTENDS FROM THE N LEEWARD ISLANDS NEAR 18N62W TO
BONAIRE IN THE ABC ISLANDS. DRY STABLE AIR ALOFT AND STRONG
SUBSIDENCE COVERS THE CARIBBEAN W OF THE UPPER TROUGH WITH MOIST
AIR ALOFT TO THE SE. A SURFACE TROUGH IS OVER THE LESSER
ANTILLES EXTENDING FROM 20N58W ACROSS MARTINIQUE INTO THE SE
CARIBBEAN JUST W OF THE WINDWARD ISLANDS TO THE COAST OF
VENEZUELA NEAR 11N62W GENERATING SCATTERED SHOWERS AND POSSIBLE
ISOLATED THUNDERSTORMS E OF THE UPPER TROUGH AXIS ACROSS THE
LESSER ANTILLES AND WITHIN 150/180 NM E OF THE SURFACE TROUGH
INTO THE W TROPICAL ATLC. ISOLATED SHOWERS REMAIN POSSIBLE
ACROSS THE REMAINDER OF THE CARIBBEAN. THE MONSOON TROUGH IS
ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 11N75W INTO THE E
PACIFIC OVER PANAMA/COSTA RICA NEAR 9N83W. STRONG SURFACE RIDGE
OVER THE SE CONUS WILL SHIFT E AND BUILD THROUGH SUN THEN SHIFT
NE WHILE WEAKENING EARLY NEXT WEEK. SURFACE TROUGH OVER THE
LESSER ANTILLES WILL SLOWLY MOVE W ACROSS THE E CARIBBEAN
THROUGH MON.

ATLANTIC OCEAN...
A SURFACE RIDGE CONTINUES TO BUILD OVER THE W ATLC FROM THE SE
CONUS AND GULF OF MEXICO. BROAD UPPER TROUGH COVERS THE W ATLC N
OF 22N W OF 55W WITH A SURFACE TROUGH EMBEDDED ALONG 29N67W
ACROSS THE TURKS AND CAICOS TO 20N73W. ISOLATED SHOWERS ARE N OF
26N BETWEEN 64W-71W. A COLD FRONT REMAINS IN THE CENTRAL ATLC
SUPPORTED BY AN UPPER TROUGH WELL N OF THE DISCUSSION AREA
ENTERING THE REGION NEAR 32N55W TO 24N56W. DRY STABLE AIR AND
STRONG SUBSIDENCE COVERS THE W ATLC W OF 56W WITH THE EXCEPTION
OF N OF 26N BETWEEN 64W-71W. A NARROW HIGH AMPLITUDE UPPER RIDGE
IS IN THE CENTRAL ATLC EXTENDING AN AXIS FROM 20N52W TO BEYOND
32N51W PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS
AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE FROM
20N54W TO BEYOND 32N55W. AN UPPER TROUGH COVERS THE E ATLC N OF
20N E OF 40W WITH AN UPPER LOW NEAR 30N32W AND SUPPORTING A 1018
MB LOW NEAR 31N27W WITH A SURFACE TROUGH EXTENDING S FROM THE
LOW ALONG 27N29W THEN W TO 24N36W. SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE N OF 27N BETWEEN 25N-33W. A SURFACE RIDGE
COVERS THE REMAINDER OF THE CENTRAL/E ATLC N OF 20N E OF 50W
WITH A WEAKNESS IN THE VICINITY OF THE ABOVE LOW/TROUGH AND
ANCHORED BY A 1037 MB HIGH N OF THE AZORES. W ATLC SURFACE RIDGE
WILL CONTINUE TO BUILD E ACROSS THE W ATLC THROUGH WEEKEND THEN
SHIFT NE AND WEAKEN EARLY NEXT WEEK.

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

$$
PAW






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