000
AXNT20 KNHC 050538
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST WED DEC 05 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 ACROSS W AFRICA INTO THE FAR E 
TROPICAL ATLC NEAR 8N13W TO 8N15W WHERE THE ITCZ BEGINS AND 
CONTINUES ALONG 6N29W 7429W 9N54W TO SOUTH AMERICA NEAR 8N60W. 
NUMEROUS TO SCATTERED STRONG CONVECTION IS FROM 4N-7N BETWEEN 
25W-31W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 30 NM OF 
LINE FROM THE COAST OF LIBERIA NEAR 5.5N10W TO 4N16W...WITHIN 60 
NM N OF THE ITCZ BETWEEN 19W-25W AND WITHIN 90 NM N OF THE ITCZ 
BETWEEN 31W-33W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION 
IS FROM 6N-10N BETWEEN 37W-41W. 

...DISCUSSION...

GULF OF MEXICO...
A SHARP NARROW UPPER TROUGH EXTENDS INTO THE GULF OVER E TEXAS 
TO NEAR 22N95W SUPPORTING A COLD FRONT THAT AT 05/0300 UTC 
EXTENDS INLAND ALONG THE COASTAL PLAINS OF TEXAS. SCATTERED 
SHOWERS/THUNDERSTORMS ARE OVER THE NW GULF N OF 26N W OF 93W TO 
INLAND OVER FAR E TEXAS. AN UPPER RIDGE EXTENDS FROM THE E GULF 
OVER THE FLORIDA PENINSULA INTO THE W ATLC. THE SURFACE RIDGE IS 
SHIFTING E AHEAD OF THE FRONT ANCHORED BY A 1026 MB HIGH ABOUT 
250 NM OFF THE COAST OF SOUTH CAROLINA. SOUTHERLY RETURN FLOW 
OVER THE NW GULF IS GENERATING SCATTERED SHOWERS/ISOLATED 
THUNDERSTORMS N OF 25N TO INLAND OVER LOUISIANA BETWEEN 89W-93W. 
ISOLATED SHOWERS ARE OVER S FLORIDA AND THE STRAITS OF FLORIDA S 
OF 25N E OF 85W. THE FRONT OVER TEXAS WILL MOVE INTO THE GULF 
WATERS OVERNIGHT THEN STALL OVER THE CENTRAL GULF WED AND 
DISSIPATE THROUGH THU. HIGH PRESSURE WILL BUILD ACROSS THE 
REGION FRI WITH FRESH SE FLOW EXPECTED W GULF THIS WEEKEND. 

CARIBBEAN SEA...
A BROAD UPPER RIDGE IN THE TROPICAL ATLC EXTENDS A RIDGE AXIS 
ALONG THE N COAST OF SOUTH AMERICA TO OVER COSTA RICA NEAR 
10N84W GIVING THE CARIBBEAN MAINLY SW TO W FLOW ALOFT. MODERATE 
TO STRONG SUBSIDENCE WITH DRY STABLE AIR ALOFT DOMINATES MOST OF 
THE CARIBBEAN TONIGHT. LIGHT TO MODERATE NE TO E TRADE WINDS 
ACROSS THE CARIBBEAN CONTINUE TO BANK SCATTERED SHOWERS AND 
POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120/150 NM ALONG THE 
COAST OF HONDURAS...NICARAGUA...AND COSTA RICA BETWEEN 81W-85W. 
A SHEAR LINE IS ANALYZED FROM THE CENTRAL ATLC BETWEEN THE 
LEEWARD AND WINDWARD ISLANDS NEAR 16N61W TO 14N71W GENERATING 
SCATTERED SHOWERS WITHIN 150 NM N OF THE SHEAR LINE. THE 
REMAINDER OF THE CARIBBEAN IS UNDER MOSTLY CLEAR SKIES TONIGHT. 
BROAD SURFACE RIDGE OVER THE W ATLC WILL MAINTAIN THE TRADE 
WINDS ACROSS MOST OF THE REGION EXCEPT FRESH TO STRONG WINDS ARE 
EXPECTED OVER THE NW CARIBBEAN AND ATLC PASSAGES THROUGH WED. 

ATLANTIC OCEAN...
AN UPPER RIDGE COVERS THE FAR E GULF INTO THE FAR W ATLC W OF 
75W. A SURFACE RIDGE DOMINATES THE W ATLC ANCHORED BY A 1026 MB 
HIGH ABOUT 250 NM OFF THE COAST OF SOUTH CAROLINA. THE EASTERLY 
SURFACE FLOW OVER THE FAR W ATLC IS GENERATING SCATTERED SHOWERS 
FROM 24N-29N W OF 77W TO OVER FLORIDA. AN UPPER TROUGH EXTENDS 
INTO THE CENTRAL ATLC THROUGH 32N53W TO 25N57W SUPPORTING A 
SURFACE TROUGH THAT EXTENDS FROM 31N38W ALONG 27N46W THROUGH A 
1010 MB LOW NEAR 24N51W TO 17N58W WHERE A SHEAR LINE CONTINUES 
INTO THE CARIBBEAN NEAR 16N61W. AN UPPER RIDGE IS TO THE E 
EXTENDING FROM 20N40W TO BEYOND 32N28W PROVIDING DIFFLUENCE 
ALOFT TO GENERATE DENSE CLOUD COVER WITH SCATTERED SHOWERS/ 
ISOLATED THUNDERSTORMS FROM 20N TO BEYOND 32N BETWEEN 36W-50W. 
AN UPPER TROUGH IS WELL N OF THE DISCUSSION AREA SUPPORTING A 
COLD FRONT THAT EXTENDS TO 31N37W. A SURFACE RIDGE DOMINATES THE 
REMAINDER OF THE E ATLC N OF 14N E OF 34W ANCHORED BY A 1030 MB 
HIGH NE OF MADEIRA ISLANDS. A WEAK COLD FRONT WILL MOVE OVER THE 
N PORTION OF THE W ATLC WED THROUGH THU. A TROUGH WILL DEVELOP N 
OF THE BAHAMAS THU AND DRIFT IN NW INTO FLORIDA THROUGH FRI. 
STRONG HIGH PRESSURE WILL BUILD NE OF THE AREA THU NIGHT THROUGH 
SUN. 

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

$$
PAW