000 AXNT20 KNHC 160546 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST FRI DEC 16 2011 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ/MONSOON TROUGH... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 11N15W TO 05N30W TO 05N41W. ISOLATED MODERATE CONVECTION IS FROM 06N-12N BETWEEN 20W-26W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE REMAINS ANCHORED IN THE WESTERN CARIBBEAN SEA AND EXTENDS NORTHWARD CONTINUING TO IMPACT THE GULF AND FLORIDA PENINSULA THIS EVENING. THE RIDGE AXIS IS ALONG 80W WITH WATER VAPOR IMAGERY INDICATING A DRY AND STABLE AIRMASS UNDER MOSTLY SOUTHWESTERLY FLOW ALOFT. THIS UPPER LEVEL FEATURE IS SUPPORTIVE OF A SURFACE RIDGE ANCHORED BY A 1024 MB HIGH CENTERED OVER THE SW NORTH ATLC NEAR 32N74W WHICH EXTENDS A RIDGE AXIS SOUTHWESTWARD ACROSS THE FLORIDA PENINSULA TO THE WESTERN GULF WATERS NEAR 23N95W. MOSTLY E TO SE WINDS IN THE RANGE OF 10 TO 15 KT ARE EXPECTED THROUGH THE OVERNIGHT HOURS. ALSO ON WATER VAPOR IMAGERY...AN UPPER LEVEL SHORTWAVE TROUGH IS PROGRESSING NE ACROSS WEST TEXAS CURRENTLY AND IS EXPECTED TO PUSH A WEAK FRONTAL BOUNDARY INTO THE NW WATERS BY SUNRISE. NORTHERLY WINDS ARE FORECAST TO INCREASE TO 20 KT BEHIND THE FRONT AND PERSIST THROUGHOUT THE DAY ON FRIDAY AS THE FRONT BECOMES DIFFUSE LATE AS THE UPPER LEVEL SHORTWAVE MOVES TO THE NE. SURFACE HIGH PRESSURE WILL THEN BUILD ACROSS THE GULF THROUGH THE WEEKEND WITH NORTHEASTERLY WINDS PERSISTING THROUGH SUNDAY NIGHT. CARIBBEAN SEA... AN UPPER LEVEL RIDGE INFLUENCES MUCH OF THE WESTERN CARIBBEAN WITH AN AXIS EXTENDING FROM OVER NORTHERN COLOMBIA NEAR 12N74W NORTHWESTWARD TO OVER THE YUCATAN CHANNEL NEAR 22N87W. SOUTHWEST OF THIS RIDGE AXIS...SOUTHERLY DIFFLUENT FLOW ALOFT CONTINUES TO ENHANCE WIDELY SCATTERED SHOWERS AND TSTMS S OF 13N BETWEEN 73W-85W...INCLUDING PORTIONS OF PANAMA...COSTA RICA...AND SOUTHERN NICARAGUA. MOST OF THIS CONVECTIVE ACTIVITY IS FOCUSED IN THE VICINITY OF THE MONSOON TROUGH AXIS WHICH EXTENDS FROM THE E PACIFIC ALONG 10N TO NORTHERN COLOMBIA. OTHERWISE THE REMAINDER OF THE WESTERN CARIBBEAN W OF 70W IS UNDER STRONG NE TRADES DUE TO AN INCREASED PRESSURE GRADIENT FROM BUILDING HIGH PRESSURE OVER THE SW NORTH ATLC. FARTHER EAST...NORTHWESTERLY FLOW ALOFT DOMINATES ON THE SOUTHWESTERN PERIPHERY OF AN UPPER LEVEL TROUGH ACROSS THE CENTRAL ATLC. A DIFFUSE AND DISSIPATING COLD FRONT EXTENDS INTO THE EASTERN CARIBBEAN THROUGH THE GUADELOUPE PASSAGE NEAR 16N62W THEN WESTWARD ALONG 15N66W TO 16N71W. ISOLATED SHOWERS ARE OCCURRING WITHIN 75 NM EITHER SIDE OF THE FRONT AS IT CONTINUES TO DRIFT SOUTHWARD. A RECENT ASCAT PASS AROUND 16/0132 UTC INDICATED STRONG NE WINDS NORTH OF THE FRONT IN THE RANGE OF 20 TO 25 KT. HIGH PRESSURE IS FORECAST TO REMAIN ANCHORED NE OF THE BAHAMAS THROUGH THE REMAINDER OF THE WEEKEND MAINTAINING AN AREA OF INCREASED E-NE TRADES. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE CONTINUES TO SLIDE EASTWARD OVER THE SW NORTH ATLC WITH AXIS ALONG 80W. A MOSTLY DRY AND STABLE AIRMASS IS ASSOCIATED WITH THIS UPPER LEVEL FEATURE AND THIS CONTINUES TO SUPPORT A 1024 MB SURFACE HIGH CENTERED NEAR 32N74W. MOSTLY NE TO E WINDS ARE OBSERVED W OF 60W WITH A FEW FAST-MOVING ISOLATED SHOWERS EXPECTED THROUGH THE OVERNIGHT ACROSS THE BAHAMAS...TURKS AND CAICOS...AND N OF 25N W OF 78W TO THE FLORIDA PENINSULA COAST. FARTHER EAST...A SHARP UPPER LEVEL TROUGH WITH AXIS ALONG 55W CONTINUES TO SUPPORT A COLD FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N48W EXTENDING SOUTH THEN SOUTHWESTWARD ALONG 26N50W TO 20N55W TO THE GUADELOUPE PASSAGE NEAR 16N62W AND INTO THE EASTERN CARIBBEAN SEA. A PRE-FRONTAL TROUGH IS LOCATED SE OF THE FRONT ALONG 13N53W TO 20N50W TO 27N47W. LOW-LEVEL CONVERGENCE NEAR THE SURFACE TROUGH AND FRONTAL BOUNDARIES ALONG WITH STRONG MIDDLE TO UPPER LEVEL DIFFLUENCE IS GENERATING A BROAD AREA OF SCATTERED SHOWERS AND ISOLATED TSTMS FROM 12N-32N BETWEEN 42W-51W. A FEW ISOLATED SHOWERS ARE ALSO OCCURRING WEST OF THE COLD FRONT FROM 24N-30N BETWEEN 52W-57W IN ASSOCIATED WITH THE MIDDLE TO UPPER LEVEL LOW CENTERED NEAR 27N55W. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1034 MB HIGH CENTERED SW OF THE IBERIAN PENINSULA NEAR 35N16W. THE RIDGE AXIS EXTENDS SW FROM THE HIGH TO 32N24W TO 15N40W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN