000 AXNT20 KNHC 271137 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST FRI DEC 27 2013 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO 07N17W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N17W TO 02N30W TO 02N40W TO THE EQUATOR NEAR 46W. ISOLATED MODERATE CONVECTION IS FROM 02N-05N BETWEEN 25W-37W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES SOUTHWESTERLY FLOW ALOFT OVER THE GULF THIS MORNING EAST OF A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDING FROM WEST TEXAS NEAR 32N103W SOUTHWARD TO A BASE NEAR 23N106W. PRIMARILY MIDDLE TO UPPER LEVEL DIFFLUENT FLOW EAST OF THE TROUGHING IS ADVECTING PLENTY OF MOISTURE NORTHEASTWARD FROM OVER MEXICO TO OVER THE GULF...SE CONUS...AND FLORIDA PENINSULA. SATELLITE IMAGERY AND MOSAIC DOPPLER RADAR IMAGERY ARE INDICATING SCATTERED SHOWERS AND A FEW ISOLATED TSTMS OCCURRING ACROSS THE GULF WITH THE EXCEPTION OF THE FAR SE GULF WATERS AND YUCATAN CHANNEL. THIS AREA IS LARGELY UNDER THE INFLUENCE OF WEAK RIDGING AT THE SURFACE...HOWEVER THE MIDDLE TO UPPER LEVEL DYNAMICS REMAIN STRONG ENOUGH TO GENERATE THE ONGOING SHOWERS AND CONVECTION. A WEAK SURFACE TROUGH ANALYZED ACROSS THE SW GULF WITH A WEAK 1016 MB LOW CENTERED NEAR 19N94W IS ALSO PROVIDING FOCUS FOR ISOLATED SHOWER AND TSTM ACTIVITY THIS MORNING. ACROSS THE SE GULF...ANOTHER SURFACE TROUGH IS ANALYZED FROM 24N88W TO 27N85W. LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE BOUNDARY IS GENERATING ISOLATED SHOWERS AND TSTMS FROM 24N-28N BETWEEN 83W-87W. OTHERWISE...DURING THE NEXT 24 TO 36 HOURS...GENERALLY E-NE WINDS WILL PERSIST IN THE RANGE OF 15 TO 25 KT. AS THE UPPER LEVEL TROUGHING STRENGTHENS OVER THE SOUTHERN PLAINS AND THEN EJECTS NORTHEASTWARD EARLY SATURDAY THROUGH SUNDAY...GLOBAL MODELS SUGGEST CYCLOGENESIS TO TAKE PLACE OVER THE WEEKEND ACROSS THE CENTRAL AND NORTH-CENTRAL PORTIONS OF THE GULF WITH THE ASSOCIATED SURFACE LOW AND FRONT QUICKLY MOVING NORTHEAST ACROSS THE SE CONUS INTO THE MID-ATLC WATERS BY LATE SUNDAY. CARIBBEAN SEA... THE WESTERN CARIBBEAN IS UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE WHICH IS PROVIDING DRY AIR AND STRONG SUBSIDENCE ALOFT W OF 65W. SKIES REMAIN MOSTLY FAIR THIS MORNING WITH THE EXCEPTION OF A FEW LOW-TOPPED ISOLATED SHOWERS AND POSSIBLE TSTMS OCCURRING ACROSS THE NW CARIBBEAN. OTHERWISE...THE MAIN FEATURE IMPACTING THE EASTERN CARIBBEAN IS A MIDDLE TO UPPER LEVEL TROUGH WITH AXIS EXTENDING FROM 20N65W SE TO A BASE NEAR 09N58W. THIS UPPER LEVEL TROUGH IS ADVECTING PLENTY OF MOISTURE NORTH- NORTHEASTWARD OVER THE WINDWARD ISLANDS AND AREAS TO THE EAST OF THE LEEWARD ISLANDS E OF 60W...GENERATING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS PORTIONS OF THE WINDWARD ISLANDS THIS MORNING AND FROM 09N-19N BETWEEN 48W-62W. TRADES ARE EXPECTED TO REMAIN IN THE 10 TO 20 KT RANGE TODAY AS A BROAD AND RELATIVELY WEAK SURFACE PRESSURE GRADIENT REMAINS IN PLACE ACROSS THE BASIN AND TO THE NORTH ACROSS THE SW NORTH ATLC. THE GRADIENT IS EXPECTED TO INCREASE SOMEWHAT BETWEEN 68W-80W EARLY SATURDAY THROUGH EARLY NEXT WEEK AS THE PRESSURE GRADIENT STRENGTHENS DUE TO THE PRESENCE OF A RE-ESTABLISHED BERMUDA HIGH. ...HISPANIOLA... CURRENTLY CONDITIONS REMAIN MOSTLY DRY AND STABLE DUE TO NORTHWESTERLY WINDS ALOFT AND OVERALL LIGHT E-SE TRADES ACROSS THE REGION. CONDITIONS SHOULD REMAIN TRANQUIL OVER THE UPCOMING WEEKEND. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY OFF THE NEW ENGLAND COAST NEAR 46N61W THAT SUPPORTS A COLD FRONT ANALYZED FROM 32N76W TO 30N80W. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED TO THE E-SE OF THE FRONT FROM THE NW BAHAMAS NEAR 25N78W TO 32N74W. SOUTHWESTERLY FLOW ALOFT OVER THE NORTHWESTERN PORTION OF THE SW NORTH ATLC...ALONG WITH THE SURFACE FRONT IS PROVIDING FOCUS FOR WIDELY SCATTERED SHOWERS AND A FEW ISOLATED TSTMS OCCURRING N OF 28N W OF 71W. THIS AREA REMAINS WITHIN A WEAKNESS OF THE SUBTROPICAL RIDGE ACROSS THE SW NORTH ATLC. FARTHER EAST...AN UPPER LEVEL TROUGH LOCATED OVER THE NORTHEASTERN NORTH ATLC EXTENDS A COLD FRONT INTO THE DISCUSSION AREA NEAR 32N35W TO 31N41W AND BECOMES STATIONARY WESTWARD TO 30N52W THEN AS A SURFACE TROUGH SW TO 27N63W. ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE BOUNDARY. OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1027 MB HIGH CENTERED NEAR 28N39W. THE ONLY PRECIPITATION NOTED WITHIN THE INFLUENCE OF THE RIDGE IS ASSOCIATED WITH AN UPPER LEVEL TROUGH EXTENDING FROM 20N65W TO 08N58W. MIDDLE TO UPPER LEVEL DIFFLUENCE IS MAXIMIZED EAST OF THE TROUGH AXIS GENERATING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS FROM 09N-19N BETWEEN 48W-62W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN