000
AXNT20 KNHC 150554
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT DEC 15 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 MOST OF AFRICA. THE ITCZ 
EXTENDS FROM OVER GUINEA AND SIERRA LEONE INTO THE E TROPICAL 
ATLC NEAR 7N12W ALONG 5N25W 6N36W TO 10N50W. SCATTERED MODERATE/ 
STRONG CONVECTION IS WITHIN 90 NM S AND 60 NM N OF THE ITCZ 
BETWEEN 23W-26W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG 
CONVECTION ARE WITHIN 45 NM ALONG THE COAST OF LIBERIA S OF 
6N...FROM 2N-6N BETWEEN 14W-19W...AND FROM 2N-6N BETWEEN 
29W-37W. 
 
...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE DOMINATES THE GULF ANCHORED IN THE E PACIFIC 
REGION EXTENDING A RIDGE AXIS ACROSS S MEXICO AND THE BAY OF 
CAMPECHE THROUGH THE GULF OF MEXICO TO OVER THE E CONUS NEAR THE 
ALABAMA/MISSISSIPPI BORDER. A SURFACE RIDGE COVERS THE GULF 
ANCHORED BY A 1025 MB HIGH OVER SOUTH CAROLINA AND A 1026 MB 
HIGH OVER PENNSYLVANIA. COLD AIR STRATOCUMULUS CLOUDS REMAIN 
OVER THE E GULF WITH WITH ISOLATED SHOWERS OVER THE SE GULF S OF 
24N BETWEEN 81W-83W. A MIX OF LOW LEVEL CLOUDS AND CIRRUS CLOUDS 
WITH POSSIBLE ISOLATED SHOWERS ARE OVER THE W GULF WITHIN 90 NM 
ALONG THE COAST FROM VERA CRUZ MEXICO TO THE LOUISIANA/TEXAS 
BORDER. SOUTHERLY RETURN FLOW WILL INCREASE IN THE W GULF SAT 
NIGHT AND SUN AHEAD OF A COLD FRONT THAT WILL MOVE ACROSS THE 
GULF MON AND TUE.  

CARIBBEAN SEA...
BROAD UPPER TROUGH DIPS S FROM THE W ATLC OVER THE CARIBBEAN N 
OF 14N. S OF 14N...NE FLOW COVERS THE CARIBBEAN W OF 80W WHILE 
SW FLOW COVERS THE AREA E OF 80W. STRONG SUBSIDENCE WITH DRY 
STABLE AIR ALOFT DOMINATES THE CARIBBEAN. HOWEVER...AN AREA OF 
LOW LEVEL SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 14N 
TO OVER HISPANIOLA BETWEEN 67W-73W INCLUDING THE MONA PASSAGE. 
NE TRADE WINDS ARE GENERATING SCATTERED LOW LEVEL SHOWERS AND 
POSSIBLE ISOLATED THUNDERSTORMS INLAND AND WITHIN 75 NM ALONG 
THE COAST OF PANAMA TO NICARAGUA S OF 13N W OF 77W LEAVING THE 
REMAINDER OF THE CARIBBEAN WITH TRANQUIL WEATHER. LIGHT TO 
MODERATE TRADE WINDS WILL PREVAIL ACROSS THE REGION THROUGH 
EARLY WED. 

ATLANTIC OCEAN...
A BROAD UPPER TROUGH COVERS THE W ATLC W OF 55W SUPPORTING A 
WEAK COLD FRONT THAT EXTENDS THROUGH 32N59W ALONG 27N66W TO JUST 
E OF THE CENTRAL BAHAMA ISLANDS NEAR 24N72W. ISOLATED SHOWERS 
ARE WITHIN 60 NM E OF THE FRONT N OF 25N. A SURFACE RIDGE IS 
BUILDING IN BEHIND THE ABOVE FRONT COVERING THE W ATLC INTO THE 
GULF OF MEXICO ANCHORED BY A 1025 MB HIGH OVER SOUTH CAROLINA 
AND A 1026 MB HIGH OVER PENNSYLVANIA. AN UPPER LOW IS IN THE 
CENTRAL ATLC NEAR 25N48W SUPPORTING A SURFACE TROUGH THAT 
EXTENDS FROM 24N51W ALONG 22N54W THROUGH A 1009 MB LOW NEAR 
20N54W CONTINUING ALONG 18N53W TO 16N54W. SCATTERED SHOWERS/ 
ISOLATED THUNDERSTORMS ARE ASSOCIATED WITH THE UPPER LOW 
COVERING THE AREA FROM 21N-26N BETWEEN 44W-47W. AN UPPER RIDGE 
IS TO THE E PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED 
SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 8N-19N BETWEEN 
40W-47W. A SURFACE RIDGE DOMINATES THE E ATLC N OF 15N E OF 45W 
ANCHORED BY A 1025 MB HIGH NEAR 28N27W. W ATLC COLD FRONT WILL 
DISSIPATE THROUGH SAT. A STRONGER COLD FRONT WILL MOVE OFF THE 
COAST OF N FLORIDA TUE.  

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

$$
PAW