000 AXNT20 KNHC 301743 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI DEC 30 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 04N08W TO 04N13W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 04N13W TO 05N16W TO 01N29W TO 02N39W TO THE EQUATOR NEAR 50W. ISOLATED MODERATE CONVECTION IS WITHIN 90 NM EITHER SIDE OF A LINE FROM 08N13N TO 04N24W...AND FROM 03N-05N BETWEEN 33W-39W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES MOSTLY WEST-SOUTHWESTERLY UPPER LEVEL FLOW OVER THE GULF THIS AFTERNOON AS AN UPPER LEVEL SHORTWAVE TROUGH APPROACHES FROM THE NW WITH AXIS FROM THE ARKLATEX REGION NEAR 33N94W TO NORTHERN MEXICO NEAR 27N105W. THIS UPPER LEVEL FEATURE IS FORECAST WEAKEN SLIGHTLY AND SKIRT TO THE NORTH OF THE GULF BASIN AS A SURFACE RIDGE...ANCHORED BY A 1022 MB HIGH CENTERED NEAR 29N77W...EXTENDS FROM THE SW NORTH ATLC ACROSS THE CENTRAL FLORIDA PENINSULA TO THE WESTERN GULF NEAR 23N98W AND WILL REMAIN IN PLACE THROUGH LATE SATURDAY. THE NEXT COLD FRONT IS EXPECTED TO ENTER THE NW GULF WATERS BY EARLY SUNDAY INTRODUCING STRONG NORTH-NORTHEASTERLY WINDS BASIN-WIDE INTO EARLY NEXT WEEK. CARIBBEAN SEA... BROAD UPPER LEVEL RIDGING IS ACROSS THE CARIBBEAN WITH WATER VAPOR IMAGERY INDICATING DRY AIR AND SUBSIDENCE EXTENDING BETWEEN THE TROPICAL NORTH ATLC ALONG 50W TO CENTRAL AMERICA AND SOUTHERN MEXICO ALONG 92W. WITH A STABLE ATMOSPHERE ALOFT...THE BASIN REMAINS TRANQUIL CONVECTIVELY...HOWEVER...AT THE SURFACE...A STRONG PRESSURE GRADIENT BETWEEN A SURFACE RIDGE OVER THE CENTRAL ATLC AND LOWER PRESSURE OVER NORTHERN SOUTH AMERICA IS PRODUCING STRONG E-NE TRADES IN THE RANGE OF 20 TO 30 KT. THESE CONDITIONS ARE EXPECTED TO PERSIST THROUGH EARLY MONDAY OF NEXT WEEK AS A COLD FRONT AND FRONTAL TROUGH ENTER THE SW NORTH ATLC RELAXING THE PRESSURE GRADIENT. ATLANTIC OCEAN... WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL SHORTWAVE TROUGH PROGRESSING NE OF THE DISCUSSION AREA OVER THE SW NORTH ATLC WITH AXIS FROM 34N64W TO 29N72W THAT SUPPORTS A STATIONARY FRONT FROM 32N64W TO 31N69W WHERE IT BEGINS DISSIPATING ALONG 28N71W TO THE CENTRAL BAHAMAS NEAR 25N76W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING N OF 29N BETWEEN 61W-68W WITH ISOLATED SHOWERS OCCURRING ELSEWHERE S OF 29N WITHIN 150 NM EITHER SIDE OF THE DISSIPATING PORTION OF THE FRONT. TO THE NW OF THE FRONT...A 1022 MB HIGH IS CENTERED NEAR 29N77W AND IS MAINTAINING GENERALLY LIGHT ANTICYCLONIC FLOW W OF 75W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF AN EXPANSIVE AND RELATIVELY STRONG 1042 MB HIGH CENTERED EAST OF THE AZORES NEAR 38N20W. THE INFLUENCE OF THE RIDGE EXPANDS SOUTHWARD TO 10N AND EXHIBITS AN AXIS EXTENDING FROM THE HIGH SW ALONG 32N36W TO 25N65W. WITH SUCH A STRONG HIGH PRESSURE SYSTEM IN PLACE...A STRONG PRESSURE GRADIENT EXISTS WITH GENERALLY MODERATE TO STRONG E-NE TRADES. EARLY MORNING ASCAT PASSES FROM 30/1050 UTC AND 30/1230 UTC INDICATED THESE STRONG TRADES WITH METEO-FRANCE METAREA II HIGH SEAS FORECASTS INDICATING POSSIBLE INTERMEDIATE GALE FORCE NE WINDS IN THE AREAS OF CAPE VERDE... CAP BLANC...AND CAP TIMIRIS LOCATED OFF THE W AFRICAN COAST FROM 15N-25N E OF 22W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN