000 AXNT20 KNHC 131140 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SAT DEC 13 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...THE ITCZ... THE ITCZ IS CENTERED ALONG 8N10W 4N24W 4N45W 2N52W. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 2N-6N BETWEEN 26W-34. ...DISCUSSION... GULF OF MEXICO... THE TAIL END OF A COLD FRONT EXTENDING FROM THE W ATLC IS ACROSS THE FLORIDA STRAITS TO NEAR 24N83W WITH POSSIBLE ISOLATED SHOWERS ACROSS THE FLORIDA STRAITS THIS MORNING. ELSEWHERE OVER THE REST OF THE GULF...BROKEN TO OVERCAST STRATOCUMULUS CLOUDS COVER THE WRN AND S/CENTRAL PORTIONS OF THE GULF...INCLUDING THE BAY OF CAMPECHE AND THE YUCATAN PENINSULA. THE LOW CLOUDS W OF 90W ARE ALREADY SHOWING SIGNS OF RETURN SOUTHERLY FLOW THAT IS IN STORE FOR THE GULF OVER THE NEXT FEW DAYS AHEAD OF THE NEXT DEVELOPING LOW PRESSURE AREA OVER THE CENTRAL U.S. PLAINS THROUGH LATE SUNDAY. IN THE MEANTIME...MODERATE TO STRONG SUBSIDENCE IN STRONG W-NW FLOW ALOFT IS INHIBITING ANY DEEP CONVECTION ACROSS THE GULF REGION WITH A SURFACE RIDGE EXTENDING ACROSS THE GULF WHICH IS ANCHORED BY A 1028 MB SURFACE HIGH OVER CENTRAL ALABAMA. CARIBBEAN SEA... A COLD FRONT OVER THE W ATLC ENTERS THE CARIBBEAN SEA THROUGH ERN CUBA THEN CONTINUES S AS A STATIONARY FRONT THROUGH 19N80W TO COASTAL NICARAGUA NEAR 12N83W. SCATTERED SHOWERS ARE ALONG AND WITHIN 90 NM ON EITHER SIDE OF THIS FRONT. BEHIND THE FRONT BROKEN TO OVERCAST CLOUDINESS WITH EMBEDDED ISOLATED SHOWERS ARE OBSERVED S OF 21N. THE REMAINDER OF THE CARIBBEAN SEA IS UNDER THE INFLUENCE OF A STRONG 1039 MB HIGH PRESSURE SYSTEM CENTERED W OF THE AZORES IN THE CENTRAL ATLC. PATCHES OF LOW LEVEL MOISTURE STREAM WWD ACROSS THE BASIN ON MODERATE TO FRESH TRADE WINDS. SATELLITE IMAGERY REVEALS LARGEST SWATH OF LOW TOPPED SHOWERS FROM 11N-16N W OF 71W. ELSEWHERE ISOLATED AREAS OF SHOWERS ARE ACROSS THE LEEWARD ISLANDS AND PUERTO RICO THIS MORNING. ALOFT...UPPER LEVEL ANTICYCLONIC FLOW RESIDES WITH A RIDGE EXTENDING FROM N COLOMBIA TO THE NW CARIBBEAN NEAR 18N83W. ATLANTIC OCEAN... A DEEP LAYERED TROUGH OVER THE ERN U.S. SEABOARD SUPPORTS A PAIR OF COLD FRONTS OVER THE W ATLC. THE MAIN FRONT ENTERS THE FORECAST AREA NEAR 32N68W AND CONTINUES SW OVER THE CENTRAL BAHAMAS TO ERN CUBA NEAR 21N77W. THE SECONDARY FRONT CONTINUES TO WEAKEN AND EXTENDS FROM 31N74W ACROSS THE NW BAHAMAS AND INTO THE STRAITS OF FLORIDA. SCATTERED SHOWERS ARE WITHIN 200 NM E OF THE MAIN FRONT N OF 26N AND WITHIN 90 NM OF THE FRONT ELSEWHERE. THE REMAINDER OF THE ATLC IS UNDER THE INFLUENCE OF A STRONG 1039 MB SURFACE HIGH CENTERED W OF THE AZORES NEAR 37N37W. SUBSIDENCE AROUND THIS HIGH IS GENERALLY SUPPORTING FAIR WEATHER CONDITIONS ACROSS MUCH OF THE ERN ATLC. HOWEVER...AN UPPER-LEVEL TROUGH WITH AXIS ALONG 32N54W 23N50W TO 18N47W AND A SURFACE TROUGH WHICH EXTENDS FROM 27N55W TO 20N50W ARE GENERATING SCATTERED SHOWERS AND TSTMS FROM 20N-28N BETWEEN 41W-53W E OF THE TROUGH. UPPER DIFFLUENCE TO THE SE OF THE UPPER TROUGH IS ALSO GENERATING SCATTERED SHOWERS FROM 8N-19N BETWEEN 33W-40W. ANOTHER SURFACE TROUGH EXTENDS ALONG 14N54W TO 9N56W WITH CYCLONIC CURVATURE NOTED IN THE LOW CLOUD FIELD. BY EARLY NEXT WEEK...COMPUTER MODELS ARE ANTICIPATING THE FORMATION OF A LOW PRESSURE SYSTEM OVER THE TROPICAL CENTRAL ATLC AS THE UPPER LEVEL DEEP LAYERED TROUGH CURRENTLY OVER THE ERN SEABOARD MOVES EWD. $$ HUFFMAN