000 AXNT20 KNHC 050003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST WED DEC 04 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE WEST AFRICAN COAST NEAR 07N12W TO 06N21W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N22W TO 06N32W TO 07N43W. SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 01N-09N BETWEEN 13W-23W. ISOLATED MODERATE CONVECTION AND TSTMS ARE FROM 05N-13N BETWEEN 25W- 40W. ...DISCUSSION... GULF OF MEXICO... WESTERLY TO NORTHWESTERLY MIDDLE TO UPPER LEVEL WIND FLOW IS NOTED ON WATER VAPOR IMAGERY ASSOCIATED WITH AN ANTICYCLONIC CIRCULATION CENTERED OVER THE SOUTHERN GULF NEAR 19N91W. MOSTLY DRY AIR AND UPPER-LEVEL STABILITY SUPPORT FAIR WEATHER CONDITIONS. AT THE SURFACE...SOUTHERLY RETURN FLOW IN THE RANGE OF 10 TO 15 KT DOMINATES. OVER THE NORTHERN GULF...MOISTURE ADVECTION FROM THE E PACIFIC BY THE ANTICYCLONE ALOFT AS WELL AS UPPER-LEVEL DIFFLUENCE SUPPORT RAINSHOWERS N OF 28 BETWEEN 85W- 89W. ISOLATED SHOWERS ARE ALSO IN THE NW GULF N OF 27N W OF 94W. A COLD FRONT CURRENTLY ANALYZED OVER THE SOUTHERN PLAINS IS FORECAST TO MOVE SOUTHEASTWARD THROUGH LATE THURSDAY AND EMERGE OFF THE TEXAS AND LOUISIANA COASTS BY EARLY TO MID-DAY FRIDAY INTO SATURDAY. CARIBBEAN SEA... NORTH-NORTHWESTERLY DRY AND STABLE WIND FLOW IN THE MIDDLE LEVELS IS NOTED W OF 70W ON WATER VAPOR IMAGERY WHICH CONTINUE TO SUPPORT CLEAR SKIES AND FAIR WEATHER ACROSS THIS REGION OF THE BASIN. OVER THE SW BASIN WITHIN 70 NM OF THE PANAMA CANAL BETWEEN 78W-82W...SCATTERED SHOWERS ARE BEING ENHANCED BY THE MONSOON TROUGH AXIS WHICH EXTENDS ACROSS NORTHERN PANAMA TO NORTHERN COLOMBIA NEAR 06N74W. A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM NOVA SCOTIA SOUTHWARD TO THE EASTERN CARIBBEAN AND SUPPORTS A SURFACE PRE-FRONTAL TROUGH CURRENTLY BEING ANALYZED FROM 23N61W TO NE PUERTO RICO NEAR 18N65W TO S OF DOMINICAN REPUBLIC NEAR 16N70W. AN ELONGATED MIDDLE TO UPPER LEVEL RIDGE EXTENDS FROM THE CENTRAL ATLC TO THE LESSER ANTILLES TO GENERATE DIFFLUENCE ALOFT AND SUPPORT RAINSHOWERS ACROSS DOMINICAN REPUBLIC...MONA PASSAGE...PUERTO RICO...THE VIRGIN ISLANDS AND NORTHERN LEEWARD ISLANDS. A WEAK PRESSURE GRADIENT ACROSS THE BASIN IS FORECAST TO PROVIDE WITH TRADEWINDS IN THE RANGE OF 10- 15 KT THROUGHOUT THU MORNING. AFTERWARDS...A TIGHTER PRESSURE GRADIENT IS EXPECTED TO DEVELOP SUPPORTING EASTERLY WINDS UP TO 20 KT ACROSS THE CENTRAL BASIN THROUGHOUT FRI NIGHT. ...HISPANIOLA... A SURFACE TROUGH IS BEING ANALYZED FROM 23N61W IN THE ATLC TO NE PUERTO RICO NEAR 18N65W TO S OF DOMINICAN REPUBLIC NEAR 16N70W. THIS AREA OF LOW PRESSURE IS SUPPORTING RAINSHOWERS ACROSS DOMINICAN REPUBLIC AND SOUTHERN ADJACENT WATERS TO 14N AS WELL AS THE MONA PASSAGE. THE BOUNDARY IS FORECAST TO REMAIN RELATIVELY STATIONARY OVER THE NEXT 24 HOURS AND GRADUALLY DISSIPATE. HOWEVER RAINSHOWERS AND TSTMS ARE FORECAST TO PERSIST ACROSS EASTERN PORTIONS OF THE ISLAND THROUGHOUT FRI NIGHT. ATLANTIC OCEAN... A BROAD MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM NOVA SCOTIA SOUTHWARD TO THE EASTERN CARIBBEAN AND SUPPORTS A COLD FRONT ANALYZED FROM 30N54W TO 25N60W TO 23N65W AS WELL AS A PRE- FRONTAL TROUGH FROM 23N61W TO NE PUERTO RICO NEAR 18N65W TO S OF DOMINICAN REPUBLIC NEAR 16N70W. AN ELONGATED MIDDLE TO UPPER LEVEL RIDGE EXTENDS FROM THE CENTRAL ATLC TO THE LESSER ANTILLES TO GENERATE DIFFLUENCE ALOFT AND SUPPORT SCATTERED MODERATE CONVECTION/ISOLATED TSTMS N OF 24N BETWEEN 47W-60W AND WITHIN 260 NM E OF THE TROUGH AXIS FROM 18N-23N. THE REMAINDER OF THE SW NORTH ATLC WEST OF THE COLD FRONT IS UNDER THE INFLUENCE OF RELATIVELY DRY AND STABLE NORTHWESTERLY FLOW ALOFT AND A SURFACE RIDGE ANCHORED BY A 1021 MB HIGH CENTERED OFF THE COAST OF THE CAROLINAS NEAR 34N70W. A DEEP LAYERED LOW IS CENTERED OVER THE EASTERN ATLC NEAR 31N28W WITH THE SURFACE LOW ANALYZED AT 996 MB. THE OCCLUDED LOW HAS A TRIPLE POINT IN THE VICINITY OF THE MADEIRA ISLANDS NEAR 34N18W WITH A WARM FRONT STRETCHING SE TO 31N14W AND A DISSIPATING COLD FRONT EXTENDING SW FROM THE TRIPLE POINT TO 21N28W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING MAINLY WITHIN 240 NM OF THE LOW CENTER. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS