000 AXNT20 KNHC 172345 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT DEC 17 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 2330 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH REMAINS INLAND ACROSS AFRICA. THE ITCZ EXTENDS WESTWARD FROM THE COAST OF SIERRA LEONE NEAR 7N13W ALONG 6N20W 7N30W 6N40W TO 6N46W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 130 NM ON EITHER SIDE OF THE AXIS BETWEEN 30W-46W. ...DISCUSSION... GULF OF MEXICO... A FRONTAL BOUNDARY CONTINUES TO SLOWLY SHIFT SE ACROSS THE NRN GULF EXTENDING FROM NRN FLORIDA AS A COLD FRONT NEAR 28N82W CONTINUING WSW ALONG 26N87W TO 26N92W...BECOMING STATIONARY AND TURNING SWD ALONG 26N95W AND MOVING INLAND INTO MEXICO S OF TAMPICO NEAR 21N97W. OVERCAST SKIES WITH LOW VISIBILITIES AND ISOLATED SHOWERS ARE WITHIN 110 NM N AND W OF THE FRONTAL BOUNDARY ALONG WITH NORTHERLY WINDS GUSTING TO 20 KTS. THE FRONT LACKS ANY STRONG UPPER LEVEL SUPPORT DUE TO DRY WESTERLY FLOW ALOFT COVERING MUCH OF THE BASIN THIS EVENING. MOSTLY FAIR CONDITIONS ARE ELSEWHERE ACROSS THE GULF WITH A FEW PATCHES OF CLOUDS AND POSSIBLE ISOLATED SHOWERS. DUE TO THE LACK OF UPPER LEVEL SUPPORT...THE FRONT IS EXPECTED TO STALL AND DISSIPATE OVER THE NEXT DAY OR SO AS HIGH PRESSURE BUILDS OVER THE REGION. CARIBBEAN SEA... SCATTERED SHOWERS AND THUNDERSTORMS ARE OVER THE SW CARIBBEAN DUE TO MONSOONAL FLOW AROUND THE AXIS ANALYZED ACROSS WRN PANAMA INTO NRN COLOMBIA. A 1010 MB LOW IS EMBEDDED IN THE MONSOONAL GYRE NEAR 10N80W. THE ACTIVITY IS AFFECTING MOSTLY THE COASTAL WATERS OF PANAMA...COSTA RICA...AND NICARAGUA WITHIN 130 NM. AN UPPER LEVEL ANTICYCLONE IS NOTICED IN THE THE UPPER LEVEL CLOUD FIELD W OF 72W...PROVIDING DIFFLUENCE ALOFT OVER THE SW CARIBBEAN HELPING PRODUCE THE CONVECTION AROUND THE MONSOON TROF. ACROSS THE S-ERN CARIBBEAN...A SHEAR LINE EXTENDS ACROSS THE FAR SE CARIBBEAN ALONG 11N62W T0 12N71W DEPICTING A WEAKENING DELINEATION BETWEEN NE AND ELY WINDS0 KTS. ISOLATED SHOWERS ARE WITHIN 70 NM N OF THE AXIS. OTHERWISE...FAIR WEATHER CONDITIONS ARE ELSEWHERE ACROSS THE DISCUSSION AREA THIS EVENING. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS WITH MOISTURE REMAINING OVER THE SW CARIBBEAN AND GENTLE TO MODERATE NE WINDS OVER THE CENTRAL AND ERN CARIBBEAN. ATLANTIC OCEAN... WEAK UPPER LEVEL RIDGING CONTINUES TO COVER THE WRN ATLC SUPPORTING A 1021 MB HIGH NEAR 27N67W...PROVIDING MOSTLY FAIR WEATHER ASIDE A FEW AREAS OF STRATOCUMULUS CLOUDS THAT MAY SOURCE A FEW ISOLATED SHOWERS W OF 58W. AN UPPER LEVEL LOW IS TO THE E NEAR 27N50W REFLECTING A SURFACE 1009 MB LOW. TWO FRONTAL BOUNDARIES ACCOMPANY THE LOW. THE MAIN FRONT IS NOW BECOMING STATIONARY WITH AN OCCLUDED PORTION ALONG 27N52W TO 29N46W THEN TURNING STATIONARY ALONG 23N45W TO 17N48W. A WEAK SURFACE TROUGH CONTINUES FARTHER TO THE SW TO 12N51W. A SECONDARY COLD FRONT EXTENDS FROM THE LOW CENTER ALONG 24N48W TO 21N51W. THE STRONGEST ACTIVITY IS E OF THE MAIN FRONT N OF 17N WITHIN 70-140 NM. SCATTERED SHOWERS AND THUNDERSTORMS ARE ALSO NEAR THE LOW CENTER FROM 24N-28N BETWEEN 47W-50W. THE REMAINDER OF THE ERN ATLC IS EXPERIENCING MOSTLY FAIR WEATHER DUE TO SURFACE RIDGING AROUND A 1034 MB HIGH S OF THE AZORES NEAR 35N25W. EXPECT THE LOW PRESSURE SYSTEM IN THE CENTRAL ATLC TO REMAIN SOMEWHAT STATIONARY WITH CONVECTION OVER THE NEXT DAY OR SO. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA