000
AXNT20 KNHC 151142
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1115 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST OF SIERRA 
LEONE. THE ITCZ EXTENDS FROM THE COAST OF SIERRA LEONE NEAR 
8N13W ALONG 5N23W 4N36W 3N46W TO SOUTH AMERICA NEAR 2N51W. 
SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 75 NM OF LINE 
FROM 4N38W TO 6N43W. CLUSTERS OF SCATTERED MODERATE/ISOLATED 
STRONG CONVECTION ARE FROM 2N-6N BETWEEN 18W-36W AND FROM 1N-7N 
BETWEEN 38W-46W. 
 
...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 FAR E CONUS 
ACROSS THE FLORIDA PANHANDLE NEAR PENSACOLA. A SURFACE RIDGE 
COVERS THE GULF ANCHORED BY A PAIR 1025 MB HIGHS OVER SOUTH 
CAROLINA AND PENNSYLVANIA. COLD AIR STRATOCUMULUS CLOUDS REMAINS 
OVER THE NE GULF WITH ISOLATED SHOWERS OVER THE SE GULF S OF 27N 
BETWEEN 82W-85W. A MIXTURE OF CLOUDS WITH POSSIBLE ISOLATED 
SHOWERS ARE OVER THE NW GULF N OF 25N W OF 91W. SOUTHERLY RETURN 
FLOW WILL INCREASE W OF 95W TONIGHT INTO SUN AHEAD OF COLD FRONT 
THAT WILL ENTER THE NW GULF LATE MON.

CARIBBEAN SEA...
BROAD UPPER TROUGH DOMINATES MOST OF THE CARIBBEAN WITH NE FLOW 
OVER THE SW CARIBBEAN S OF 12W W OF 79W. STRONG SUBSIDENCE WITH 
DRY STABLE AIR ALOFT DOMINATES THE CARIBBEAN. HOWEVER...A WEAK 
SURFACE TROUGH IS OVER THE CENTRAL CARIBBEAN EXTENDING FROM 
HISPANIOLA NEAR 18N70W TO THE COAST OF VENEZUELA NEAR 12N69W 
WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 14N TO OVER 
HISPANIOLA BETWEEN 68W-74W 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 12N W OF 75W 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 32N57W ALONG 27N63W TO 
25N68W WHERE IT BECOMES A STATIONARY TO JUST E OF THE CENTRAL 
BAHAMA ISLANDS NEAR 24N75W. ISOLATED SHOWERS ARE WITHIN 60 NM E 
OF THE COLD FRONT. A WEAK SURFACE TROUGH EXTENDS FROM 31N81W 
JUST OFF THE COAST OF FLORIDA TO 27N80W WITH ISOLATED SHOWERS W 
OF THE TROUGH TO INLAND OVER GEORGIA AND FLORIDA. A SURFACE 
RIDGE CONTINUES TO BUILD IN BEHIND THE ABOVE FRONT COVERING THE 
W ATLC INTO THE GULF OF MEXICO ANCHORED BY A PAIR OF 1025 MB 
HIGHS OVER SOUTH CAROLINA AND PENNSYLVANIA. A WEAKENING UPPER 
LOW IS IN THE CENTRAL ATLC NEAR 24N46W SUPPORTING A SURFACE 
TROUGH THAT EXTENDS FROM 24N50W ALONG 22N52W THROUGH A 1009 MB 
LOW NEAR 20N52W CONTINUING ALONG 18N53W TO 16N55W. AN UPPER 
RIDGE IS TO THE E PROVIDING DIFFLUENCE ALOFT TO GENERATE 
SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 
200/250 NM OF LINE FROM 8N45W 20N41W TO 32N42W. A SURFACE RIDGE 
DOMINATES THE E ATLC N OF 18N E OF 40W ANCHORED BY A 1025 MB 
HIGH NEAR 29N21W. W ATLC COLD FRONT WILL DISSIPATE TODAY. A 
STRONGER COLD FRONT WILL MOVE OFF THE COAST OF N FLORIDA TUE.  

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

$$
PAW