000 AXNT20 KNHC 191745 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST THU DEC 19 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ/MONSOON TROUGH... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS ALONG 04N13W TO 04N24W TO 06N34W TO THE EQUATOR NEAR 49W. WHILE NO SIGNIFICANT CONVECTION IS NOTED ALONG THE ITCZ AXIS...A SURFACE TROUGH ANALYZED FROM 07N34W TO 16N31W REMAINS EMBEDDED WITHIN THE ITCZ AXIS AND IS LARGELY A SURFACE REFLECTION OF A VIGOROUS MIDDLE TO UPPER LEVEL LOW CENTERED NEAR 19N35W. LOW-LEVEL MOISTURE CONVERGENCE ALONG THE SURFACE TROUGH IN TANDEM WITH MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE IS GENERATING A LARGE AREA OF CLOUDINESS AND ISOLATED MODERATE CONVECTION FROM 08N-24N BETWEEN 20W-35W. ...DISCUSSION... GULF OF MEXICO... WEAK UPPER LEVEL RIDGING IS NOTED ALOFT OVER THE GULF THIS AFTERNOON THAT IS FURTHER SUPPORTING THE SURFACE RIDGE CURRENTLY ANALYZED ACROSS THE BASIN. A 1028 MB HIGH IS CENTERED OFF THE COAST OF THE CAROLINAS NEAR 34N78W THAT EXTENDS A RIDGE AXIS SW TO 25N90W TO A 1022 MB HIGH CENTERED INLAND ACROSS EAST-CENTRAL MEXICO NEAR 20N98W. SOUTH-SOUTHEAST WINDS PREVAIL ACROSS MOST OF THE BASIN IN THE RANGE OF 10 TO 20 KT WITH THE POSSIBILITY OF 15 TO 25 KT OVER FAR NORTHWESTERN PORTIONS N OF 24N W OF 95W. OTHERWISE...GENERALLY CLEAR SKIES DOMINATE WITH ONLY A FEW ISOLATED SHOWERS ADVECTING NORTHWARD ACROSS THE NW GULF THIS AFTERNOON. THE SOUTHERLY RETURN FLOW IS FORECAST TO INCREASE BY EARLY SATURDAY AS A COMPLEX AREA OF LOW PRESSURE DEVELOPS ACROSS THE SOUTHERN PLAINS AND LOWER MISSISSIPPI RIVER VALLEY. THE NEXT COLD FRONT IS EXPECTED TO EMERGE OFF THE TEXAS AND LOUISIANA COASTS EARLY SUNDAY. CARIBBEAN SEA... WATER VAPOR IMAGERY INDICATES A BROAD MIDDLE TO UPPER LEVEL RIDGE OVER THE CARIBBEAN WITH THE AIRMASS REMAINING RELATIVELY MORE MOIST ALOFT W OF 72W. OVERALL STABILITY FILTERS DOWN TO THE SURFACE WHERE ONLY A FEW PASSING ISOLATED LOW-TOPPED SHOWERS ARE NOTED ON SATELLITE IMAGERY OCCURRING ACROSS THE SE CARIBBEAN... IN THE VICINITY OF THE MONA PASSAGE...AND ALONG THE CENTRAL AMERICA COASTLINE. SLIGHTLY DEEPER CONVECTION IS OCCURRING S OF 11N IN THE SW CARIBBEAN DUE TO THE CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS. OTHERWISE...TRADES ARE EXPECTED TO PERSIST IN THE RANGE OF 15 TO 25 KT THROUGH EARLY SATURDAY AND GRADUALLY INCREASE OVER THE WEEKEND DUE TO A STRENGTHENED PRESSURE GRADIENT BETWEEN HIGH PRESSURE ACROSS THE SW NORTH ATLC AND LOWER PRESSURE ACROSS NORTHERN SOUTH AMERICA. ...HISPANIOLA... CURRENTLY RELATIVELY DRY AIR AND STABLE CONDITIONS ALOFT PREVAIL WITH SATELLITE IMAGERY INDICATING ONLY LOWER LEVEL CLOUDINESS AND POSSIBLE ISOLATED SHOWERS OCCURRING TO THE WEST OF THE ISLAND. THE OVERALL STABILITY WILL LIKELY LIMIT ANY SIGNIFICANT CONVECTION...HOWEVER AN ISOLATED SHOWER CANNOT BE RULED OUT DURING THE LATE AFTERNOON AND EARLY EVENING HOURS WITH PEAK DAYTIME HEATING AND INSTABILITY OCCURRING NEAR THE SURFACE. LOOKING AHEAD...A MOSTLY NORMAL PATTERN OF WINTER TIME TRADES IS EXPECTED TO CONTINUE ACROSS THE ISLAND WITH WINDS INCREASING SLIGHTLY INTO FRIDAY DUE TO A STRENGTHENING PRESSURE GRADIENT ACROSS THE REGION. THE STRONG TRADES WILL PERSIST DURING THE UPCOMING WEEKEND. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS OVER THE WESTERN NORTH ATLC AND SUPPORTS A COLD FRONT INTO THE DISCUSSION AREA NEAR 32N57W SW TO THE NW BAHAMAS NEAR 25N78W. AN OLDER REMNANT FRONTAL BOUNDARY...NOW ANALYZED AS A SURFACE TROUGH IS NOTED SE OF THE COLD FRONT FROM 30N58W SW TO THE CENTRAL BAHAMAS NEAR 23N76W. MOST OF THE LOWER LEVEL MOISTURE IS ASSOCIATED WITH THE SURFACE TROUGH WITH ISOLATED SHOWERS OCCURRING WITHIN 120 NM EITHER SIDE OF THE BOUNDARY. OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC NW OF THE COLD FRONT IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1028 MB HIGH CENTERED OFF THE CAROLINA COAST NEAR 34N78W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS ALSO UNDER THE INFLUENCE OF A BROAD SURFACE RIDGE ANCHORED BY A 1036 MB HIGH CENTERED IN THE VICINITY OF THE AZORES NEAR 38N26W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN