000 AXNT20 KNHC 121140 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SUN DEC 12 2010 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 1100 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED FROM LIBERIA NEAR 6N9W ALONG 5N20W 7N33W 6N45W 4N54W. A SURFACE TROUGH EXTENDS FROM S OF THE CAPE VERDE ISLANDS NEAR 13N20W TO 6N30W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 3N-8N BETWEEN 29W-35W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM 3N-8N BETWEEN 38W-45W. ...DISCUSSION... GULF OF MEXICO... AS OF 0900 UTC...A COLD FRONT PUSHES ACROSS THE CENTRAL GULF FROM THE FLORIDA PANHANDLE NEAR FORT WALTON BEACH AT 31N86W CONTINUING ALONG 26N92W 23N98W. A SQUALL LINE WITH ASSOCIATED STRONG SHOWERS/THUNDERSTORMS IS AHEAD OF THE FRONT FROM THE SW CORNER OF GEORGIA TO PANAMA CITY FLORIDA. SCATTERED SHOWERS ARE ALSO WITHIN 90 NM AHEAD OF THE FRONT. THE SYSTEM IS SUPPORTED BY A LONGWAVE UPPER LEVEL TROUGH EXTENDING FROM THE UPPER MIDWEST OVER THE NW GULF AND ACROSS CENTRAL MEXICO. NLY WINDS UP TO 30 KT ARE NOTED BEHIND THE FRONT. AS THE FRONT PUSHES FARTHER SE...GALE FORCE WINDS ARE EXPECTED BEHIND IT WITHIN 6 HRS. THE REMAINDER OF THE BASIN IS EXPERIENCING MOSTLY FAIR WEATHER UNDER DRY AIR IN MAINLY ZONAL WLY FLOW ALOFT. EXPECT THE FRONT TO CONTINUE TO RACE ACROSS THE GULF AND REACH S FLORIDA LATE TONIGHT. CARIBBEAN SEA... DRY AIR AND SUBSIDENCE AROUND AN UPPER LEVEL RIDGE CENTERED OVER NW COLOMBIA IS KEEPING MUCH OF THE CARIBBEAN UNDER FAIR CONDITIONS THIS MORNING. A SHEARLINE EXTENDS FROM THE SW TIP OF HAITI NEAR 18N75W TO THE PANAMA COAST ALONG 15N79W 9N80W. THE AXIS DEPICTS A LINE OF SURFACE CONVERGENCE BETWEEN N-NE WINDS ACROSS THE NW CARIBBEAN AND NE-E TRADE WINDS ACROSS THE REMAINDER OF THE BASIN. THE SURFACE CONVERGENCE IS SUPPORTING ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS WITHIN 60 NM EITHER SIDE OF THE AXIS. SOME SHOWERS ARE ALSO ACROSS THE MONA PASSAGE ATTRIBUTED TO A SURFACE TROUGH IN THE W ATLC THAT REACHES THROUGH THE PASSAGE AND WRAPS AROUND THE SRN SHORE OF HISPANIOLA. EXPECT A LINE OF SHOWERS TO CONTINUE IN THE CENTRAL CARIBBEAN AS NLY WINDS INCREASE IN THE NW PORTION OF THE AREA AHEAD OF THE COLD FRONT THAT IS MOVING ACROSS THE GULF OF MEXICO. THE FRONT SHOULD REACH THE NW CARIBBEAN EARLY MONDAY. ATLANTIC OCEAN... MAINLY ZONAL FLOW ALOFT COVERS THE W AND CENTRAL ATLC. DESPITE THE LACK OF UPPER LEVEL SUPPORT...A SURFACE TROUGH EXTENDS ALONG 32N55W 28N60W 26N64W CONTINUING AS A SHEARLINE ALONG 27N71W 26N76W. ISOLATED SHOWERS ARE WITHIN 45 NM OF THE TROUGH AND SHEAR AXIS. A SECOND SURFACE TROUGH IS TO THE SOUTH ALONG 25N58W 22N64W TO THE MONA PASSAGE AT 18N68W WITH ISOLATED SHOWERS WITHIN 30 NM OF THE AXIS. TO THE E OF THIS BOUNDARY...STRONGER SHOWERS/POSSIBLE THUNDERSTORMS ARE FROM 22N-26N BETWEEN 46W-57W ASSOCIATED WITH AN UPPER LEVEL JET IN THE ZONAL WLY FLOW ALOFT. THE REMAINDER OF THE E ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1018 MB HIGH NEAR 26N42W. THE RIDGE IS SUPPORTED BY A BROAD UPPER LEVEL RIDGE WITH AXIS FROM NRN S AMERICA TO THE AZORES ISLANDS. A COLD FRONT CLIPS THE DISCUSSION AREA N OF THE RIDGE ALONG 32N34W 30N42W 31N49W. SCATTERED SHOWERS ARE WITHIN 75 NM EITHER SIDE OF THE AXIS. AN UPPER LEVEL TROUGH COVERS THE FAR E ATLC EXTENDING FROM THE CANARY ISLANDS TO THE CAPE VERDE ISLANDS. THIS UPPER LEVEL TROUGH IS ENHANCING CONVECTION ALONG THE ITCZ AND THE SURFACE TROUGH EMBEDDED WITHIN THE AXIS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON