000 AXNT20 KNHC 210558 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST TUE DEC 21 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURE... A 1009 MB LOW PRESSURE CENTER IS NEAR 12N56W...ABOUT 200 NM TO THE EAST-SOUTHEAST OF BARBADOS. A SURFACE TROUGH EXTENDS FROM 13N54W TO THE LOW CENTER TO 7N60W IN NORTHERN GUYANA. ISOLATED MODERATE RAINSHOWERS COVER THE WATERS FROM 8N TO 14N BETWEEN 48W AND 60W. IT IS POSSIBLE THAT THIS SYSTEM MAY BECOME A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. THIS SYSTEM WILL BRING LOCALLY HEAVY RAINFALL AND GUSTY WINDS TO MUCH OF THE LESSER ANTILLES DURING THE NEXT DAY OR SO EVEN IF IT NEVER DEVELOPS INTO A TROPICAL CYCLONE. ...THE ITCZ... FROM THE LIBERIA COAST NEAR 5N9W TO 3N16W 4N27W 2N40W TO THE EQUATOR ALONG 50W NEAR NORTHEASTERN COASTAL BRAZIL. NUMEROUS STRONG RAINSHOWERS AND THUNDERSTORMS ARE FROM 4N TO 6N BETWEEN 6W AND 11W...IN THE SOUTHWESTERN CORNER OF THE IVORY COAST AND IN SOUTHERN LIBERIA. DISORGANIZED ISOLATED MODERATE RAINSHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE ELSEWHERE TO THE SOUTH OF 9N TO THE EAST OF 51W. UPPER LEVEL SOUTHWESTERLY WINDS ARE WITHIN ABOUT 500 NM TO THE SOUTHEAST OF THE LINE THAT GOES FROM 17N36W TO 24N20W BEYOND 26N15W ACROSS THE WESTERN SAHARA. A BROAD SURFACE-TO-LOW LEVEL TROUGH APPEARS TO CONNECT LOOSELY THE 1009 MB 12N53W LOW PRESSURE CENTER TO 12N45W TO 14N37W. ISOLATED MODERATE RAINSHOWERS ARE FROM 10N TO 15N BETWEEN 33W AND 45W. ...DISCUSSION... THE GULF OF MEXICO... BROAD UPPER LEVEL ANTICYCLONIC FLOW SPANS THE AREA BETWEEN 80W AND 113W IN THE EASTERN PACIFIC OCEAN. A SURFACE RIDGE EXTENDS FROM A 1022 MB HIGH PRESSURE CENTER THAT IS NEAR 30N84W IN NORTH CENTRAL FLORIDA TO 27N89W 23N93W AND THE ISTHMUS OF TEHUANTEPEC OF MEXICO. FROM THE ATLANTIC OCEAN TO THE WEST OF 50W...AND THEN INTO THE CENTRAL CARIBBEAN SEA... BROAD CYCLONIC FLOW ON WATER VAPOR IMAGERY THAT COVERS THE ATLANTIC OCEAN BETWEEN 50W AND 80W IS ASSOCIATED WITH THE LONGWAVE TROUGH THAT PASSES THROUGH 32N63W TO 27N64W TO TO THE TURKS AND CAICOS ISLANDS. THE TROUGH SUPPORTS THE COLD FRONT THAT PASSES THROUGH 32N55W TO 25N57W...THROUGH 20N61W TO THE VIRGIN ISLANDS AND 18N66W IN THE CARIBBEAN SEA. A SURFACE TROUGH CURVES FROM 18N66W TO 16N69W TO COASTAL VENEZUELA NEAR 12N70W. ISOLATED MODERATE RAINSHOWERS ARE WITHIN 30 NM ON EITHER SIDE THE LINE THAT PASSES THROUGH 32N52W 27N53W 21N57W 19N61W 18N64W 15N70W 12N70W. GALE FORCE WINDS ARE TO THE NORTH OF 27N WITHIN 240 NM TO THE EAST OF THE FRONT...WITH SEA HEIGHTS RANGING FROM 9 FEET TO 14 FEET. GALE FORCE WINDS ALSO ARE TO THE NORTH OF 28N BETWEEN THE FRONT AND 73W...WITH SEA HEIGHTS RANGING FROM 16 FEET TO 21 FEET. THE REST OF THE CARIBBEAN SEA... MIDDLE LEVEL TO UPPER LEVEL NORTHWESTERLY WIND FLOW IS MOVING ACROSS THE NORTHWESTERN CORNER OF THE AREA. MIDDLE LEVEL SOUTHWESTERLY WIND FLOW IS ABOUT 240 NM TO THE SOUTHEAST OF THE LINE THAT GOES FROM EASTERN HONDURAS BEYOND HISPANIOLA. NORTHERLY SURFACE-TO-LOW LEVEL WINDS COVER THE AREA THAT IS TO THE WEST OF 70W. A SURFACE-TO-LOW LEVEL TROUGH IS ALONG 17N63W TO 15N65W TO 13N67W. RAINSHOWERS ARE POSSIBLE FROM 12N TO 16N BETWEEN 61W AND 68W. THE REST OF THE ATLANTIC OCEAN... A LONGWAVE TROUGH ON WATER VAPOR IMAGERY PASSES THROUGH 34N22W TO 28N22W TO 24N23W. A SURFACE TROUGH GOES FROM 31N9W IN MOROCCO TO 25N14W IN THE COASTAL WESTERN SAHARA. SURFACE ANTICYCLONIC WIND FLOW COVERS THE AREA TO THE NORTH OF 10N BETWEEN 19W AND 50W. THE ANTICYCLONIC FLOW MOVES AROUND A RIDGE THAT GOES FROM 21N19W TO 22N31W...TO A 1020 MB HIGH PRESSURE CENTER THAT IS NEAR 25N40W...BEYOND 32N42W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT