[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110543
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST TUE DEC 11 2012

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 MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO
07N19W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
07N19W TO 04N24W TO 04N36W. SCATTERED MODERATE CONVECTION IS
FROM 06N-12N BETWEEN 38W-51W.

...DISCUSSION...

GULF OF MEXICO...
BROAD MIDDLE TO UPPER LEVEL TROUGHING IS OVER THE CONUS WHICH IS
PROVIDING MUCH OF THE GULF WITH SOUTHWESTERLY FLOW ALOFT. THE
TROUGHING SUPPORTS A COLD FRONT ANALYZED INTO THE GULF REGION
ACROSS THE FLORIDA PANHANDLE ALONG 30N87W TO 27N90W TO THE
MEXICO COAST NEAR 20N97W. ISOLATED SHOWERS ARE OCCURRING WITHIN
30 NM EITHER SIDE OF THE FRONT E OF 90W...AND ACROSS MUCH OF THE
WESTERN GULF W OF 90W. ANOTHER IMPACT WITH THE FRONT IS GALE
FORCE NORTHERLY WINDS FOLLOW IN WAKE OF THE FRONT S OF 26N.
WINDS ARE FORECAST TO DIMINISH BELOW GALE FORCE THROUGH THE
OVERNIGHT HOURS...BUT REMAIN IN THE RANGE OF 20 TO 30 KT.
OTHERWISE...THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF
WEAK PRE-FRONTAL TROUGHING WITH ISOLATED SHOWERS AND TSTMS
OCCURRING FROM 23N-28N E OF 87W...INCLUDING PORTIONS OF THE
CENTRAL AND SOUTHWESTERN FLORIDA PENINSULA. THE COLD FRONT IS
EXPECTED TO CONTINUE MOVING EASTWARD INTO THE SW NORTH ATLC AND
NW CARIBBEAN BY THURSDAY AS HIGH PRESSURE BUILDS IN ACROSS THE
GULF WITH PERSISTENT N-NE WINDS.

CARIBBEAN SEA...
MUCH OF THE BASIN THIS EVENING IS UNDER TRANQUIL CONDITIONS AS
WATER VAPOR IMAGERY INDICATES AN UPPER LEVEL RIDGE WITH AXIS
ALONG 73W IS PROVIDING A RELATIVELY DRY AND STABLE ATMOSPHERE. A
FEW ISOLATED SHOWERS AND TSTMS ARE HOWEVER OCCURRING OVER
PORTIONS OF THE SW CARIBBEAN S OF 11N DUE TO CLOSE PROXIMITY OF
THE MONSOON TROUGH AXIS WHICH EXTENDS FROM THE EASTERN PACIFIC
REGION ALONG 09N TO NORTHERN COLOMBIA NEAR 09N77W. OTHERWISE...A
FEW PASSING LOW-TOPPED ISOLATED SHOWERS ARE NOTED ON SATELLITE
IMAGERY ACROSS WESTERN HISPANIOLA...THE ADJACENT COASTAL WATERS
SURROUNDING PUERTO RICO...AND THE SE CARIBBEAN S OF 15N E OF
66W. WHILE CONDITIONS ARE CONVECTIVELY QUIET...THE EXISTING
PRESSURE GRADIENT BETWEEN A STRONG CENTRAL ATLC RIDGE AND LOWER
PRESSURE ACROSS NORTHERN SOUTH AMERICA IS PROVIDING FOR ENHANCED
EASTERLY TRADE WIND FLOW IN THE RANGE OF 20 TO 30 KT. THESE
TRADES ARE EXPECTED TO PERSIST THROUGH LATE THURSDAY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL RIDGE IS OVER THE SW NORTH ATLC WITH
AXIS EXTENDING NORTHWARD ALONG 74W FROM THE WESTERN CARIBBEAN
SEA. WATER VAPOR IMAGERY INDICATES FAIR DRY AIR REMAINS S OF
27N...HOWEVER WITH THE APPROACH OF A FRONTAL TROUGH CURRENTLY
OVER THE SE CONUS AND EASTERN GULF OF MEXICO...SCATTERED SHOWERS
AND TSTMS ARE OCCURRING ACROSS PORTIONS OF THE FLORIDA
PENINSULA...AND SW NORTH ATLC WATERS N OF 28N BETWEEN 74W-80W.
OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC AND CENTRAL ATLC
ARE UNDER THE INFLUENCE OF A 1027 MB HIGH CENTERED NEAR 31N50W.
A SURFACE RIDGE AXIS EXTENDS W-SW FROM THE HIGH TO THE BAHAMAS
AND CUBA. FARTHER EAST...AN UPPER LEVEL TROUGH IS NOTED ON WATER
VAPOR IMAGERY IN THE VICINITY OF 28N48W THAT CONTINUES TO
SUPPORT A STATIONARY FRONT ANALYZED FROM 32N25W TO 23N31W THAT
BECOMES A SHEAR LINE SW TO 10N60W. ISOLATED SHOWERS AND TSTMS
ARE OCCURRING WITHIN 90 NM EITHER SIDE OF THE STATIONARY FRONT.
AS FOR THE SHEAR LINE...RECENT SCATTEROMETER PASSES INDICATE THE
PRESENCE OF THE AXIS WITH STRONGER WINDS TO THE NORTH AND WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING WITHIN 240 NM
EITHER SIDE OF THE SHEAR LINE AXIS.

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

$$
HUFFMAN




This weather bulletin was brought to you by:
www.nashvilleweather.net