000
AXNT20 KNHC 041743
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST TUE DEC 04 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 
1652 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE FAR E 
TROPICAL ATLC NEAR 7N13W. THE ITCZ BEGINS NEAR 7N14W AND 
CONTINUES ALONG 6N30W 7N46W TO SOUTH AMERICA NEAR 9N61W. A 
SURFACE TROUGH EXTENDS FROM 19N50W TO 14N52W. CLUSTERS OF 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 2N-9N 
BETWEEN 27W-45W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE 
FROM 6N-14N BETWEEN 55W-61W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE RIDGE CONTINUES TO DOMINATE THE GULF THIS MORNING 
ANCHORED BY A 1027 MB HIGH OFF THE COAST OF SOUTH CAROLINA. AN 
UPPER RIDGE IS OVER THE GULF ALONG 90W IN RESPONSE TO AN UPPER 
TROUGH DIGGING S FROM THE PLAIN STATES ACROSS TEXAS INTO N 
MEXICO. ALOFT AND OVER CENTRAL AND EASTERN GULF DRY AIR 
DOMINATES PROVIDING FAIR WEATHER TO THESE PORTIONS OF THE GULF. 
MOISTURE ASSOCIATED TO THE UPPER LEVEL TROUGH COMBINED WITH 
SOUTHERLY RETURN FLOW OVER THE NW GULF CONTINUES TO PRODUCE 
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF 28N 
TO INLAND OVER THE N GULF COAST AND S OF LOUISIANA. FRESH 
EASTERLY WINDS IN THE SE GULF WILL DIMINISH AS THE SURFACE RIDGE 
WEAKENS TODAY. A WEAK FRONT IS EXPECTED TO MOVE INTO THE NW GULF 
LATE TONIGHT STALLING OVER THE CENTRAL GULF WED AND DISSIPATING 
THU. 

CARIBBEAN SEA...
A BROAD UPPER RIDGE IN THE TROPICAL ATLC IS GIVING THE CARIBBEAN 
MAINLY SW TO W FLOW ALOFT. MODERATE TO STRONG SUBSIDENCE WITH 
DRY STABLE AIR ALOFT CONTINUES TO DOMINATE THE CARIBBEAN 
PROVIDING FAIR WEATHER CONDITIONS TO MOST OF THE REGION. REMNANT 
LOW LEVEL MOISTURE IS GENERATING SCATTERED SHOWERS ABOUT 70 NM S 
OF PUERTO RICO AS INDICATED BY THE RADAR. THE SURFACE RIDGE IN 
THE W ATLC WILL MAINTAIN LIGHT TO MODERATE NE TRADE WINDS ACROSS 
MOST OF CARIBBEAN WITH PERIODS OF FRESH TO STRONG WINDS IN THE 
NW CARIBBEAN AND ATLC PASSAGES THROUGH WED.  

ATLANTIC OCEAN...
A SURFACE RIDGE DOMINATES MOST OF THE W ATLC ANCHORED BY A 1027 
MB HIGH OFF THE COAST OF SOUTH CAROLINA. AN UPPER TROUGH 
CONTINUES TO DIG S INTO THE W/CENTRAL ATLC REINFORCING A 
SHORTWAVE UPPER TROUGH THAT IS SUPPORTING A SURFACE TROUGH THAT 
EXTENDS FROM 26N51W THROUGH A 1011 MB LOW NEAR 23N53W TO 17N60W. 
SCATTERED MODERATE SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS 
ARE OBSERVED NW OF THE SURFACE FROM 24N-32N BETWEEN 35W-52W. 
THIS CONVECTION IS ALSO ASSOCIATED TO A SURFACE TROUGH ALONG 
31N36W TO 25N46W THAT IS A EXTENSION OF THE COLD FRONT THAT 
EXTENDS TO 31N35W.  A SURFACE RIDGE DOMINATES THE 
REMAINDER OF THE E ATLC N OF 18N E OF 34W ANCHORED BY A 1034 MB 
HIGH NEAR 35N17W. 


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

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NAR/CAB