[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141143
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED DEC 14 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 INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N12W TO
05N25W TO 07N37W TO 04N52W. ISOLATED MODERATE CONVECTION IS FROM
05N-11N BETWEEN 26W-36W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE REMAINS IN CONTROL OVER THE ENTIRE GULF
BASIN THIS MORNING WITH WATER VAPOR IMAGERY INDICATING MOSTLY
DRY AND STABLE CONDITIONS ALOFT. AT THE SURFACE...A RIDGE AXIS
EXTENDS FROM THE EASTERN CONUS SOUTHWARD INTO THE GULF FROM THE
FLORIDA PANHANDLE NEAR 30N85W TO THE SW GULF NEAR 20N97W. EAST
TO SOUTHEASTERLY WINDS IN THE RANGE OF 15 TO 20 KT ARE NOTED ON
RECENT SHIP...BUOY...AND OFFSHORE OIL PLATFORMS...AS WELL AS
EARLIER ASCAT PASSES AROUND 14/0218 UTC AND 14/0356 UTC. THE
RIDGE IS FORECAST TO GRADUALLY SHIFT EASTWARD AS A VIGOROUS
UPPER LEVEL TROUGH CURRENTLY ACROSS THE SW CONUS MOVES SLOWLY
EASTWARD. PROGRESSIVE SHORTWAVE ENERGY EJECTED FROM THE TROUGH
IS EXPECTED TO MOVE NE ACROSS THE SOUTHERN PLAINS AND INTRODUCE
A WEAK FRONTAL BOUNDARY TO THE NW GULF LATE THURSDAY INTO EARLY
FRIDAY. THE FRONT IS FORECAST TO STALL OVER THE NORTHERN GULF
WATERS AND DISSIPATE OVER THE WEEKEND.

CARIBBEAN SEA...
AN UPPER LEVEL RIDGE INFLUENCES MUCH OF THE CARIBBEAN THIS
MORNING WITH AN AXIS EXTENDING FROM OVER VENEZUELA NEAR 07N63W
NORTHWESTWARD TO OVER THE YUCATAN CHANNEL NEAR 21N86W. ON THE
WESTERN PERIPHERY OF THE RIDGE W OF 70W...SOUTHERLY DIFFLUENT
FLOW ALOFT CONTINUES TO PROVIDE ENHANCEMENT TO ISOLATED SHOWERS
AND TSTMS S OF 14N BETWEEN 76W-86W...INCLUDING PORTIONS OF
PANAMA...COSTA RICA...AND NICARAGUA. MOST OF THIS CONVECTIVE
ACTIVITY IS FOCUSED IN THE VICINITY OF THE MONSOON TROUGH AXIS
WHICH EXTENDS FROM THE E PACIFIC ALONG 09N TO NORTHERN COLOMBIA.
OTHERWISE...NE TRADES ARE EXPECTED TO REMAIN STRONGEST OVER THE
WESTERN CARIBBEAN...NORTHWEST OF A SHEAR LINE ANALYZED FROM THE
WINDWARD PASSAGE SW TO 16N80W...THROUGH THURSDAY AND SPREAD
EASTWARD AS STRONGER SURFACE HIGH PRESSURE BUILDS IN ACROSS THE
SW NORTH ATLC WATERS FRIDAY REMAINING NEARLY STATIONARY OVER THE
WEEKEND.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY ACROSS THE
WESTERN NORTH ATLC WITH AXIS EXTENDING INTO THE DISCUSSION AREA
ALONG 32N62W TO 23N71W. THIS UPPER LEVEL FEATURE SUPPORTS A COLD
FRONT ANALYZED FROM 32N58W TO 25N64W TO 22N70W WHICH BECOMES A
SHEAR LINE TO THE WINDWARD PASSAGE NEAR 20N74W. WHILE THE FRONT
LACKS ANY SIGNIFICANT CONVECTION IN ITS VICINITY...A PRE-FRONTAL
TROUGH EXTENDS FROM NEAR 31N58W TO 24N60W TO THE LEEWARD ISLANDS
NEAR 17N62W WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING
FROM 20N-32N BETWEEN 51W-58W...AND ISOLATED SHOWERS OCCURRING
FARTHER SOUTH FROM 11N-20N BETWEEN 43W-58W. THE REMAINDER OF THE
SW NORTH ATLC IS UNDER THE INFLUENCE OF NW FLOW ALOFT AND
RELATIVELY STABLE CONDITIONS NW OF THE COLD FRONT. MOSTLY BRISK
N-NE WINDS ARE NOTED ON AN EARLIER ASCAT PASS AND FAST MOVING
ISOLATED SHOWERS ARE POSSIBLE THROUGHOUT THE DAY WEDNESDAY.
ELSEWHERE EAST OF 50W...A SURFACE RIDGE REMAINS IN PLACE
ANCHORED BY A 1030 MB HIGH CENTERED NEAR 33N27W.

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

$$
HUFFMAN




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