[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 150548
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...

THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 05N20W TO
04N30W TO 07N49W. SCATTERED MODERATE CONVECTION IS FROM 05N-07N
BETWEEN 20W-31W.

...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 30N83W TO THE SW GULF NEAR 19N97W. 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 AN
EARLIER ASCAT PASS AROUND 15/0218 UTC. THE RIDGE IS FORECAST TO
GRADUALLY SHIFT EASTWARD AS AN UPPER LEVEL TROUGH CURRENTLY
ACROSS THE SW CONUS MOVES SLOWLY EASTWARD. PROGRESSIVE SHORTWAVE
ENERGY EJECTED FROM THE 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
EVENING WITH AN AXIS EXTENDING FROM OVER NORTHERN COLOMBIA NEAR
10N74W NORTHWESTWARD TO OVER WESTERN CUBA NEAR 22N82W. WITHIN
THE WESTERN PERIPHERY OF THE RIDGE W OF 75W...SOUTH-
SOUTHWESTERLY DIFFLUENT FLOW ALOFT CONTINUES TO PROVIDE
ENHANCEMENT TO ISOLATED SHOWERS AND TSTMS S OF 13N 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 NW AND NORTH-CENTRAL
CARIBBEAN THROUGH THE OVERNIGHT HOURS 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 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 32N60W TO 20N57W. THIS UPPER LEVEL FEATURE SUPPORTS A COLD
FRONT ANALYZED FROM 32N52W TO 23N60W TO HISPANIOLA NEAR 19N70W.
A PRE-FRONTAL TROUGH EXTENDS FROM THE FRONT NEAR 27N54W TO
14N55W 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 THROUGH THE OVERNIGHT HOURS
ACROSS MUCH OF THE REGION W OF 60W...INCLUDING THE BAHAMAS...
TURKS AND CAICOS...AND PORTIONS OF THE SOUTHERN FLORIDA
PENINSULA AND FLORIDA STRAITS. ELSEWHERE EAST OF 45W...A SURFACE
RIDGE REMAINS IN PLACE ANCHORED BY A 1032 MB HIGH CENTERED NEAR
36N19W.

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

$$
HUFFMAN



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