000
AXNT20 KNHC 071755
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST FRI DEC 07 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1730 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF 
SIERRA LEONE. THE ITCZ BEGINS AT THE COAST NEAR 7N13W AND 
CONTINUES ALONG 5N25W 8N36W ENDING NEAR 6N47W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-8N BETWEEN 
38W-47W. SCATTERED MODERATE CONVECTION IS FROM 1N-3N BETWEEN 
19W-26W. ISOLATED MODERATE CONVECTION ASSOCIATED WITH A SURFACE 
TROUGH N OF THE ITCZ EXTENDING ALONG 47W DOT THE AREA FROM 
10N-14N BETWEEN 44W-50W. 

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE EXTENDS FROM ACROSS MEXICO TO OVER THE 
MISSISSIPPI VALLEY COUPLED WITH A MIDDLE TO UPPER LEVEL TROUGH 
THAT EXTENDS JUST E OF THE FLORIDA PENINSULA PROVIDING MOSTLY NW 
FLOW ALOFT IN THE GULF. THE MIDDLE TO UPPER LEVEL TROUGH IS 
SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 25N83W NW TO 
28N89W AND ANOTHER SURFACE TROUGH THAT EXTENDS ALONG THE FLORIDA 
PENINSULA NEAR 81W. IN 24 HOURS...THE SURFACE TROUGH WILL 
DISSIPATE AND HIGH PRESSURE WILL BUILD ACROSS THE GULF.

CARIBBEAN SEA...
IN THE MIDDLE TO UPPER LEVEL...A RIDGE IS OVER W TROPICAL ATLC 
AND CENTRAL CARIBBEAN WITH AXIS NEAR 68W. THIS RIDGE IS 
PROVIDING THE REGION SW TO W FLOW ALOFT. A SURFACE TROUGH IS IN 
THE WESTERN CARIBBEAN S OF CUBA EXTENDING FROM 14N79W TO 21N80W. 
THE WATER VAPOR IMAGERY SHOWS A REGION OF MOISTURE S OF PUERTO 
RICO AND HISPANIOLA THAT IS PRODUCING SCATTERED 
MODERATE/ISOLATED STRONG SHOWERS FROM 15N TO 19N BETWEEN 64W AND 
75W. THE REMAINDER OF THE CARIBBEAN IS UNDER MODERATE DRY AIR 
SUBSIDENCE THAT IS PROVIDING FAIR WEATHER CONDITIONS. IN THE 
NEXT 24 HOURS...TRADE WINDS OF 10-20 KT WILL DOMINATE THE 
CENTRAL AND EASTERN CARIBBEAN.
 
ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL SHORT WAVE TROUGH EXTENDS FROM SOUTH 
CAROLINA TO E OF THE FLORIDA PENINSULA NEAR 21N87W. THIS 
FEATURE IS GENERATING A REGION OF SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION FROM 20N-34N BETWEEN 75W-80W. SCATTERED 
SHOWERS ARE OVER THE BAHAMAS DUE TO WIND CONFLUENCE FROM THE 
UPPER LEVEL SHORT WAVE AND THE RIDGE THAT POSITIONS OVER THE 
CENTRAL CARIBBEAN. IN THE CENTRAL ATLC...AN UPPER LEVEL TROUGH N 
OF 30N WITH AXIS NEAR 50W IS SUPPORTING A STATIONARY FRONT THAT 
EXTENDS FROM A COLD FRONT NEAR 31N54W AND THEN WESTWARD TO 
29N64W 30N71W 32N78W AND E OF GEORGIA COAST NEAR 31N80W. THE 
UPPER LEVEL TROUGH ALSO SUPPORTS A COLD FRONT THAT EXTENDS FROM 
30N33W 21N37W 15N45W. THE FRONT IS DISSIPATING FROM 15N46W 
13N51W TO 13N57W. A SURFACE TROUGH EXTENDING ALONG 47W S OF THE 
DISSIPATING COLD FRONT IS PRODUCING ISOLATED MODERATE CONVECTION 
FROM 10N TO 14N BETWEEN 44W AND 50W. IN THE E ATLC...A SURFACE 
HIGH OF 1028 MB IS ANCHORED NEAR 28N15W WITH RIDGE EXTENDING SW 
TO N OF 17N AND E OF 32W.  

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

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NAR/MT