000 AXNT20 KNHC 251139 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SAT DEC 25 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 1130 UTC. ...THE ITCZ... ITCZ AXIS IS ANALYZED FROM THE COAST OF LIBERIA NEAR 7N11W WESTWARD ALONG 3N20W 3N30W 4N40W TO THE COAST OF BRAZIL NEAR 2N50W. SCATTERED MODERATE CONVECTION IS WITHIN 30 NM ON EITHER SIDE OF THE AXIS BETWEEN 11W AND 43W. ...DISCUSSION... GULF OF MEXICO... A STRONG UPPER LEVEL SHORTWAVE QUICKLY MOVES ACROSS THE NW GULF SUPPORTING A 1014 MB LOW OFF THE COAST OF LOUISIANA NEAR 30N92W. A COLD FRONT EXTENDS SW FROM THE LOW CENTER TO VERACRUZ MEXICO. A PRE-FRONTAL SURFACE TROUGH IS STARTING TO DEVELOP SOUTH OF THE LOW CENTER NEAR 28N91W EXTENDING S TO NEAR 23N92W. MOSAIC DOPPLER RADAR IMAGERY INDICATED A LINE OF HEAVY SHOWERS AND THUNDERSTORMS N OF 23N WITHIN 40 NM EAST OF THE FRONT AND PRE-FRONTAL TROUGH. STRONG SUBSIDENCE ALOFT IS NOTED BEHIND THE FRONT ON WATER VAPOR IMAGERY. THIS SYSTEM WILL CONTINUE TO TRACK EASTWARD ACROSS THE NORTHERN GULF WITH MODERATE TO STRONG CONVECTION AFFECTING THE COASTAL WATERS OF LOUISIANA... MISSISSIPPI...ALABAMA...AND THE FLORIDA PANHANDLE OVER THE NEXT 18 HOURS. FAIR WEATHER CONDITIONS ARE ELSEWHERE AT THE MOMENT. CARIBBEAN SEA... DRY AIR AND SUBSIDENCE ALOFT IS NOTED ON WATER VAPOR IMAGERY OVER THE NW CARIBBEAN WITH MOSTLY ZONAL FLOW ALOFT ACROSS THIS AREA. HOWEVER...THE FLOW TURNS MORE SOUTHWESTERLY ELSEWHERE ACROSS THE REGION...AROUND AN UPPER LEVEL HIGH CENTERED OVER THE EASTERN TROPICAL ATLC. THIS IS BRINGING DEEP MOISTURE FROM NORTHERN SOUTH AMERICA TO MUCH OF THE SOUTHERN HALF OF THE CARIBBEAN...AS WELL AS ENHANCING CONVECTION FOCUSED ALONG A SHEAR AXIS EXTENDING ACROSS THE SOUTHERN CARIBBEAN ALONG 14N61W 13N70W 10N80W. NNE FLOW N OF THE BOUNDARY AND TRADE WINDS S OF THE BOUNDARY ARE CONVERGING ALONG THE AXIS TO GENERATE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 60 NM EITHER SIDE OF THE LINE. COMPUTER MODELS SUGGEST THE CONVECTION WILL LINGER OVER THE AREA FOR THE NEXT FEW DAYS. SCATTERED SHOWERS ARE ALSO OVER PUERTO RICO AND HISPANIOLA N OF 16N BETWEEN 65W AND 75W DUE TO A WEAKENING COLD FRONT MAKING ITS WAY IN FORM THE ATLC. THESE SHOWERS ARE EXPECTED TO LINGER OVER THE NEXT 24 HOURS AS THE COLD FRONT LOOSES MOMENTUM AND BECOMES NEAR STATIONARY IN THIS REGION. ATLANTIC OCEAN... AN UPPER RIDGE THAT COVERS THE FAR W ATLC W OF 60W PROVIDING RELATIVELY FAIR WEATHER CONDITIONS ACROSS THE AREA. HOWEVER...A LARGE AND BROAD DEEP LAYER TROUGH IS OVER THE NORTH CENTRAL ATLC BY A 966 MB LOW CENTERED E OF NEWFOUNDLAND NEAR 48N47W THAT CONTINUES TO EXTEND INFLUENCE OVER MUCH OF THE CENTRAL ATLC. THIS SYSTEM SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N39W AND EXTENDS SW ALONG 24N50W TO THE DOMINICAN REPUBLIC NEAR 18N69W. ISOLATED SHOWERS ARE WITHIN 30 NM E OF THE FRONT WITH DENSE LOW LEVEL CLOUDS AND POSSIBLE ISOLATED SHOWERS WITHIN 60 NM W OF THE FRONT WITH WINDS UP TO 30 KT. COLD AIR STRATOCUMULUS CLOUDS COVER THE REMAINDER OF THE ATLC W OF THE FRONT. TO THE SW OF THIS FRONT INTO THE WEST TROPICAL ATLC...A PRE-FRONTAL TROUGH IS ANALYZED FROM 23N47W TO 18N53W TO 12N56W SUPPORTING ISOLATED SHOWERS AND THUNDERSTORMS WITHIN 60 NM EAST OF THE AXIS N OF 18N. A SHEAR AXIS IS WEST OF THE SURFACE TROUGH FROM 15N57W WSW INTO THE CARIBBEAN SEA WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 30 NM EITHER SIDE OF THE LINE. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1020 MB HIGH CENTERED NEAR 28N23W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA