000 AXNT20 KNHC 091755 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST THU DEC 08 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ... ITCZ AXIS IS ALONG 10N14W 07N20W 05N40W 01N50W. ISOLATED MODERATE CONVECTION IS FROM 02N-08N BETWEEN 08W-15W...WITHIN 120 NM NORTH OF THE AXIS BETWEEN 20W-29W...AND FROM 04N-07N BETWEEN 39W-49W. ...DISCUSSION... GULF OF MEXICO... AS OF 09/1500 UTC...WATER VAPOR IMAGERY INDICATES A SHARP UPPER LEVEL IS LOCATED OVER THE EASTERN GULF THAT SUPPORTS A 1015 MB LOW IS CENTERED ALONG THE NW COAST OF CUBA NEAR 23N84W. A COLD FRONT TRAILS SOUTHWEST FROM THE LOW ALONG 20N88W TO INLAND OVER THE YUCATAN PENINSULA AND SE MEXICO TO NEAR 17N94W AND A WARM FRONT ALSO EXTENDS SOUTHEAST FROM THE LOW ANALYZED OVER WESTERN CUBA INTO THE THE NW CARIBBEAN SEA TO NEAR 21N79W. REGIONAL MOSAIC DOPPLER RADAR IMAGERY FROM ACROSS SOUTHERN FLORIDA AND CUBA INDICATE NUMEROUS SHOWERS OCCURRING N OF 23N WITHIN 240 NM EAST OF THE UPPER LEVEL TROUGH AXIS WHICH IS ALONG 32N81W TO 20N90W LINE. MOST OF THE SHOWER ACTIVITY IS ENHANCED DUE TO MIDDLE TO UPPER LEVEL DIFFLUENCE AS WELL AS LOW-LEVEL CONVERGENCE FOCUSED ALONG A SURFACE TROUGH ANALYZED FROM THE LOW CENTER TO BEYOND 25N80W. THE SURFACE LOW IS FORECAST TO DRIFT SE WHILE GRADUALLY WEAKENING OVER THE NEXT 24 HOURS AND TRANSITION TO SURFACE TROUGHING OVER THE WESTERN CARIBBEAN SEA BY EARLY FRIDAY. WHILE THE COLD FRONT LACKS ANY SIGNIFICANT CONVECTION... STRONG N TO NE WINDS CONTINUE OVER THE SE GULF S OF 25N E OF 90W. A SURFACE RIDGE IS GRADUALLY BUILDING OVER THE NW GULF... WITH WINDS ALREADY HINTING AT SOUTHEASTERLY RETURN FLOW ALONG THE TEXAS GULF COAST. THESE SE WINDS WILL INCREASE AHEAD OF THE NEXT COLD FRONT FORECAST TO ENTER THE NW GULF WATERS EARLY SUNDAY. CARIBBEAN SEA... WATER VAPOR IMAGERY INDICATES VERY DRY SOUTHWESTERLY FLOW ALOFT IS LOCATED OVER THE NW CARIBBEAN EAST OF AN UPPER LEVEL TROUGH SWEEPING ACROSS THE EASTERN GULF OF MEXICO. A COLD FRONT EXTENDS SW FROM A 1015 MB LOW CENTERED NEAR 23N84W AND WILL INTRODUCE NW WINDS TO THE NW CARIBBEAN THROUGH THE EVENING HOURS. FARTHER EAST...A SURFACE TROUGH IS ANALYZED THROUGH THE WINDWARD PASSAGE AND TRANSITIONS TO A SHEARLINE THAT MEANDERS FROM THE APPROACH TO THE WINDWARD PASSAGE NEAR 19N75W INTO A 1009 MB LOW CENTERED NEAR 10N78W. STRONGER N-NE WINDS AND EASTERLY TRADES CONVERGE ALONG THE AXIS OF THE SHEAR LINE AND INTO THE LOW PRESSURE CENTER PROVIDING FOCUS FOR SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 120 NM WEST OF AND 240 NM EAST OF THE BOUNDARY. THIS AREA OF CONVECTIVE ACTIVITY LIES ON THE WESTERN PERIPHERY OF AN UPPER LEVEL ANTICYCLONE CENTERED IN THE TROPICAL NORTH ATLC NEAR 10N60W. EAST OF THE SHEAR LINE...LOW-LEVEL MOISTURE CONTINUES TO STREAM FROM THE CENTRAL ATLC OVER THE EASTERN CARIBBEAN AND PROVIDE THE LESSER ANTILLES...PUERTO RICO...AND US/UK VIRGIN ISLANDS WITH ISOLATED SHOWERS THROUGH THE REMAINDER OF THE AFTERNOON AND EVENING HOURS. ATLANTIC OCEAN... A SHARP UPPER LEVEL TROUGH IS ALONG THE EASTERN U.S. SEABOARD WITH AXIS EXTENDING ACROSS NORTHERN FLORIDA AND INTO THE EASTERN GULF OF MEXICO. THIS UPPER LEVEL FEATURE SUPPORTS A COLD FRONT ANALYZED FROM 32N69W TO 30N74W THEN BECOMES STATIONARY TO 27N79W AND A SURFACE TROUGH ALONG THE SE COAST OF FLORIDA AND FLORIDA STRAITS. NUMEROUS SHOWERS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE BOUNDARIES. FARTHER SE...A SURFACE TROUGH IS ANALYZED FROM 28N68W TO THE WINDWARD PASSAGE NEAR 20N74W. THIS TROUGH FALLS WITHIN A WEAKNESS OF THE SUBTROPICAL RIDGE THAT IS GENERALLY PROVIDING FAIR CONDITIONS OVER MUCH OF THE CENTRAL ATLC BETWEEN 28W-62W. HOWEVER...LOW-LEVEL CONVERGENCE IN THE VICINITY OF THE SURFACE TROUGH IS PROVIDING FOCUS FOR SCATTERED SHOWERS AND ISOLATED TSTMS COVERING THE AREA FROM 18N-26N BETWEEN 62W-74W. THIS AREA OF CONVECTIVE ACTIVITY FALLS UNDER AN UPPER LEVEL DIFFLUENT ENVIRONMENT DUE TO A BROAD UPPER LEVEL RIDGE WITH AXIS ALONG 58W. OVER THE EASTERN ATLC...AN UPPER LEVEL LOW IS CENTERED NORTH OF THE AREA NEAR 36N24W THAT DIPS TROUGHING TO 05N. THESE UPPER LEVEL FEATURES SUPPORT A 1002 MB LOW CENTERED NEARBY THE MADEIRA ISLANDS NEAR 34N19W WITH A DISSIPATING COLD FRONT ANALYZED ALONG 32N14W 25N17W TO 19N28W. ISOLATED SHOWERS...MORE CLOSELY ASSOCIATED WITH THE UPPER LEVEL LOW FEATURE...ARE OCCURRING N OF 29N BETWEEN 19W-24W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN