000
AXNT20 KNHC 120551
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST FRI DEC 12 2008

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0515 UTC.

...THE ITCZ...
THE ITCZ IS CENTERED ALONG 8N14W 4N30W 8N50W 9N56W 8N60W. A 
SURFACE TROUGH REMAINS EMBEDDED WITHIN THE ITCZ ALONG 57W S OF 
13N. SCATTERED MODERATE CONVECTION IS FROM 7N-14N BETWEEN 
39W-50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 
4N-8N BETWEEN 54W-58W.  
 
...DISCUSSION...

GULF OF MEXICO...
AN EXTRATROPICAL CYCLONE CONSISTING OF TWO SEPARATE LOW CENTERS 
IS OVER NORTH CAROLINA AND CONTINUES TO PRODUCE A WIDE VARIETY 
OF PRECIPITATION OVER THE ERN CONUS AS IT MOVES OFF TO THE NE. A 
COLD FRONT EXTENDS FROM THE WRN MOST LOW ACROSS GEORGIA AND THE 
FLORIDA PANHANDLE INTO THE CENTRAL GULF NEAR 24N90W. A DEEP 
LAYERED TROUGH IS ACROSS THE ERN CONUS WITH THE BASE DIPPING TO 
NEAR 24N AND SUPPORTING THIS FRONT. BANDS OF ISOLATED SHOWERS 
EMBEDDED WITHIN BROKEN TO OVERCAST STRATOCUMULUS CLOUDS COVER 
MUCH OF THE GULF E OF 94W DUE TO COLD AIR ADVECTION OVER THE 
WARMER GULF WATERS. THICK LOW LEVEL CLOUDS ARE BANKED UP AGAINST 
THE MOUNTAINS IN SE MEXICO AND ALSO COVER THE BAY OF CAMPECHE S 
OF 20N. A SURFACE RIDGE CENTERED ON A 1025 MB HIGH LOCATED OVER 
NRN MEXICO IS BUILDING IN OVER THE WRN GULF. THE TIGHT PRESSURE 
GRADIENT BETWEEN THIS SURFACE RIDGE AND THE SURFACE LOWS OVER N 
CAROLINA IS RESULTING IN GALE FORCE WINDS ACROSS THE NE GULF.

CARIBBEAN SEA...
A COLD FRONT EXTENDS FROM THE W ATLC ACROSS CENTRAL CUBA AND THE 
W CARIBBEAN ALONG 22N81W INTO NRN HONDURAS NEAR 15N85W. 
SCATTERED SHOWERS ARE WITHIN 120 NM E OF THE FRONT WITH BROKEN 
TO OVERCAST LOW TO MIDDLE LEVEL CLOUDS LINGERING BEHIND THE 
FRONT OVER THE NW CARIBBEAN AND PORTIONS OF NRN CENTRAL AMERICA. 
THE REMAINDER OF THE CARIBBEAN SEA REMAINS ON THE SW SIDE OF A 
STRONG 1040 MB HIGH PRESSURE SYSTEM ANCHORED W OF THE AZORES. 
PATCHES OF LOW LEVEL MOISTURE USHERED IN ON MODERATE TO FRESH 
TRADE WINDS CONTINUE TO MOVE EWD ACROSS THE CENTRAL AND ERN 
CARIBBEAN. SATELLITE IMAGERY REVEALS BANDS OF BROKEN SHALLOW  
SHOWERS FROM 14N-18N BETWEEN THE LEEWARD ISLANDS AND JAMAICA. 
THE UPPER LEVELS HOWEVER REMAIN RELATIVELY DRY WITH THE 
STRONGEST SUBSIDENCE LOCATED OVER THE SE CARIBBEAN. SCATTERED 
MODERATE CONVECTION IS OVER PANAMA AND COSTA RICA IN THE 
VICINITY OF A 1007 MB SURFACE LOW LOCATED NEAR 10N75W. UPPER 
DIFFLUENCE ASSOCIATED WITH AN UPPER RIDGE OVER WRN COLOMBIA IS 
ENHANCING THIS ACTIVITY.

ATLANTIC OCEAN...
A STRONG SURFACE LOW COMPLEX IS SPINNING OVER THE ERN US 
SEABOARD AND SUPPORTS A COLD FRONT THAT ENTERS THE FORECAST AREA 
NEAR 32N78W THEN CONTINUES S ACROSS GRAND BAHAMA ISLAND TO 
CENTRAL CUBA AND INTO THE CARIBBEAN SEA. SCATTERED SHOWERS AND 
TSTMS ARE WITHIN 200 NM E OF THE FRONT OVER THE W ATLC. 
SUBSIDENCE AROUND A STRONG 1040 MB SURFACE HIGH PRESSURE 
CENTERED W OF THE AZORES IS GENERALLY SUPPORTING FAIR WEATHER 
CONDITIONS ACROSS MUCH OF THE CENTRAL AND E ATLC. HOWEVER...AN 
UPPER LOW CENTERED NEAR 28N52W IS PRODUCING SCATTERED SHOWERS 
FROM 21N-28N BETWEEN 46W-54W. THIS SURFACE HIGH IS ALSO 
GENERATING A WIDE SWATH OF MODERATE TO STRONG ELY WINDS ACROSS 
THE OCEAN PARTICULARLY FROM 20N-32N BETWEEN 30W-60W. ACROSS THE 
DEEP TROPICS...A MAINLY WESTERLY FLOW ALOFT IS PRESENT WITH A 
SMALL CORE OF 70-90KT JET-STREAM WINDS CROSSING N OF THE CAPE 
VERDE ISLANDS ALONG 20N E OF 25W.

$$
HUFFMAN