000 AXNT20 KNHC 162348 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2300 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE ITCZ EXTENDS ACROSS FAR WRN AFRICA TO THE COAST OF LIBERIA NEAR 7N11W CONTINUING W ALONG 6N25W 7N43W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 45 NM EITHER SIDE OF THE AXIS BETWEEN 27W-39W. ...DISCUSSION... THE GULF OF MEXICO... A COLD FRONT IS SLOWLY MAKING ITS WAY ACROSS THE NW GULF OF MEXICO FROM THE CENTRAL LOUISIANA COAST NEAR 29N92W ALONG 27N95W TO THE MEXICAN COAST NEAR 22N98W WHERE IT CONTINUES AS A STATIONARY FRONT TO THE NW. SCATTERED SHOWERS ARE WITHIN 75 NM BEHIND NW OF THE FRONT ALONG WITH N-NE WINDS UP TO 20 KTS. THE REMAINDER OF THE BASIN IS EXPERIENCING MOSTLY FAIR WEATHER WITH A FEW PATCHES OF LOW CLOUDS AND POSSIBLE ISOLATED SHOWERS ESPECIALLY IN THE SW CORNER IN THE BAY OF CAMPECHE. ALOFT...SWLY FLOW COVERS THE AREA AROUND AN UPPER LEVEL RIDGE EXTENDING FROM THE WRN CARIBBEAN INTO THE W ATLC. THE FRONT IS EXPECTED TO STALL OVERNIGHT AND DISSIPATE OVER THE NEXT COUPLE OF DAYS AS A SURFACE RIDGE BUILDS ACROSS THE BASIN. THE CARIBBEAN SEA... MUCH OF THE NRN CARIBBEAN IS EXPERIENCING MOSTLY FAIR WEATHER DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE EXTENDING FROM NRN COLOMBIA TO CENTRAL CUBA. THIS PATTERN IS ALSO PROVIDING DIFFLUENCE ALOFT OVER THE SW CARIBBEAN...WHICH COMBINED WITH SURFACE CONVERGENCE NEAR THE MONSOON TROUGH EXTENDING ACROSS COSTA RICA AND PANAMA TO NRN COLOMBIA IS HELPING PRODUCE SCATTERED SHOWERS/THUNDERSTORMS S OF 14N BETWEEN 75W-85W. ACROSS THE ERN CARIBBEAN...A SHEAR LINE EXTENDS FROM MARTINIQUE NEAR 15N61W TO N OF COLOMBIA ALONG 13N67W 13N75W PRODUCING ISOLATED SHOWERS WITHIN 45 NM TO EITHER SIDE. NELY WINDS OF 20-25 KTS ARE TO THE N OF THE AXIS IN THE CENTRAL CARIBBEAN...WITH 15 KT WINDS ACROSS THE ERN. A FORMING COLD FRONT IS ALSO APPROACHING THE NRN LEEWARD ISLANDS WHICH IS ALREADY PRODUCING ISOLATED SHOWERS AHEAD OF IT WHICH WILL LIKELY IMPACT THE ISLANDS SHORTLY. ALSO EXPECT SHOWER/THUNDERSTORM ACTIVITY TO CONTINUE OVER THE SW CARIBBEAN FOR THE NEXT SEVERAL DAYS. THE ATLANTIC OCEAN... UPPER LEVEL RIDGING COVERS THE WRN ATLC SUPPORTING A 1024 MB HIGH NEAR 30N72W PROVIDING MOSTLY FAIR WEATHER ACROSS THE WRN ATLC. A NARROW UPPER LEVEL TROUGH IS ALONG 53W NOW APPEARS TO BE BECOMING A CUT-OFF UPPER LEVEL LOW NEAR 28N53W. THE UPPER LOW/TROUGH IS SUPPORTING A 1006 MB SURFACE LOW NEAR 24N52W. A DISSIPATING FRONT IS AROUND THE LOW CENTER ALONG 26N52W 23N49W 19N53W TO THE LESSER ANTILLES NEAR 15N61W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE MAINLY NE OF THE LOW CENTER FROM 23N-30N BETWEEN 47W-54W. ISOLATED SHOWERS ARE WITHIN 150 NM S OF THE FRONTAL BOUNDARY. A SECONDARY FORMING COLD FRONT IS NW OF THE DISSIPATING FRONT EXTENDING FROM THE LOW CENTER AT 24N52W ALONG 22N51W 19N58W 19N68W. ISOLATED SHOWERS ARE WITHIN 45 NM AHEAD OF THE FRONT BETWEEN 60W-68W. THE UPPER TROUGH IS ALSO SUPPORTING A SECOND 1005 MB SURFACE LOW FARTHER E NEAR 27N46W. A SURFACE TROUGH EXTENDS SWD FROM THE LOW CENTER ALONG 19N47W 11N51W 8N55W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE E OF THE TROUGH FROM 10N-31N BETWEEN 39W-46W UNDER THE AREA OF STRONGEST DIFFLUENCE ALOFT. THE ERN ATLC IS UNDER THE INFLUENCE OF SURFACE RIDGING ANCHORED BY A 1034 MB HIGH BETWEEN THE AZORES AND MADEIRA ISLANDS NEAR 36N20W PROVIDING MOSTLY FAIR WEATHER. ALOFT...AN UPPER LEVEL RIDGE COVERS MUCH OF THE ERN ATLC WITH AXIS ALONG 38W. HOWEVER...AN UPPER LEVEL LOW DISRUPTS THE UPPER RIDGE NEAR 22N27W...BUT IS CAUSING LITTLE SIGNIFICANT WEATHER BESIDES A FEW UPPER LEVEL CLOUDS E OF THE CAPE VERDE ISLANDS. EXPECT THE FRONTAL SYSTEM IN THE CENTRAL ATLC TO LIFT N AND GRADUALLY SHIFT E BEFORE BEING SWEPT UP BY THE NEXT FRONTAL SYSTEM EARLY NEXT WEEK. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON