000
AXNT20 KNHC 151142
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST THU DEC 15 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 07N13W TO 
03N28W TO 07N49W TO 06N57W. SCATTERED MODERATE CONVECTION IS 
FROM 04N-10N BETWEEN 21W-35W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE REMAINS IN CONTROL OVER THE ENTIRE GULF 
BASIN WITH WATER VAPOR IMAGERY INDICATING MOSTLY DRY AND STABLE 
CONDITIONS ALOFT. AT THE SURFACE...A RIDGE AXIS EXTENDS ALONG 
THE EASTERN SEABOARD SOUTHWESTWARD ACROSS NORTHERN FLORIDA AND 
INTO THE GULF ALONG 30N82W TO THE SW GULF AND YUCATAN PENINSULA 
NEAR 19N91W. SURFACE WINDS CONTINUE TO VEER SOUTHEAST TO SOUTH 
ON THE WESTERN PERIPHERY OF THE RIDGE IN THE RANGE OF 15 TO 20 
KT AS NOTED ON RECENT SHIP...BUOY...AND SEVERAL OFFSHORE OIL 
PLATFORMS...AS WELL AS AN EARLIER ASCAT PASS AROUND 15/0336 UTC. 
THE RIDGE IS FORECAST TO GRADUALLY SHIFT EASTWARD AS AN UPPER 
LEVEL TROUGH CURRENTLY ACROSS THE SW CONUS AND NW MEXICO MOVES 
SLOWLY EASTWARD. ENERGY FROM THE UPPER LEVEL TROUGH IS EXPECTED 
TO MOVE E-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 NORTHERN COLOMBIA NEAR 
11N74W NORTHWESTWARD TO OVER WESTERN CUBA NEAR 22N85W. WITHIN 
THE WESTERN PERIPHERY OF THE RIDGE W OF 75W...SOUTH- 
SOUTHWESTERLY DIFFLUENT FLOW ALOFT CONTINUES TO ENHANCE WIDELY 
SCATTERED SHOWERS AND TSTMS S OF 13N BETWEEN 75W-85W...INCLUDING 
PORTIONS OF PANAMA...COSTA RICA...AND SOUTHERN 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 NW AND NORTH-CENTRAL CARIBBEAN 
THROUGHOUT THURSDAY AND SPREAD EASTWARD OVER THE REMAINDER 
OF THE BASIN AS STRONGER SURFACE HIGH PRESSURE BUILDS IN ACROSS 
THE SW NORTH ATLC WATERS THROUGH FRIDAY. THE HIGH IS EXPECTED TO 
REMAIN ANCHORED NE OF THE BAHAMAS THROUGH THE REMAINDER OF THE 
WEEKEND MAINTAINING THE AREA OF INCREASED E-NE TRADES.

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 32N58W TO 21N58W. THIS UPPER LEVEL FEATURE SUPPORTS A COLD 
FRONT ANALYZED FROM 32N51W TO 20N60W TO NORTHEASTERN PUERTO RICO 
NEAR 18N66W. A PRE-FRONTAL TROUGH EXTENDS FROM THE FRONT NEAR 
26N54W TO 13N56W WITH SCATTERED SHOWERS AND TSTMS OCCURRING 
WITHIN 300 NM EAST OF THE FRONT AND SURFACE TROUGH N OF 14N. 
ISOLATED SHOWERS ARE OCCURRING ELSEWHERE WITHIN 75 NM EITHER 
SIDE OF THE FRONT W OF 55W. THE REMAINDER OF THE SW NORTH ATLC 
IS UNDER THE INFLUENCE OF NW FLOW ALOFT AND RELATIVELY STABLE 
CONDITIONS WEST OF THE COLD FRONT. MOSTLY N-NE WINDS IN THE 
RANGE OF 20 TO 30 KT ARE NOTED ON AN EARLIER ASCAT PASS AROUND 
15/0154 UTC WITH FAST MOVING ISOLATED SHOWERS POSSIBLE 
THROUGHOUT THE DAY ON THURSDAY ACROSS MUCH OF THE REGION W OF 
60W...INCLUDING THE BAHAMAS...TURKS AND CAICOS...AND PORTIONS OF 
THE SOUTHERN FLORIDA PENINSULA. ELSEWHERE EAST OF 45W...A 
SURFACE RIDGE REMAINS IN PLACE ANCHORED BY A 1032 MB HIGH 
CENTERED NEAR 36N16W.

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

$$
HUFFMAN