000 AXNT20 KNHC 060538 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST TUE DEC 06 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST. THE ITCZ AXIS ENTERS THE E TROPICAL ATLC NEAR 11N15W CONTINUING ALONG 5N25W 6N39W TO 8N50W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 45 NM OF 3N BETWEEN 12W-14W AND WITHIN 180 NM N OF THE ITCZ BETWEEN 35W-41W. CLUSTERS OF SIMILAR CONVECTION ARE WITHIN 150 NM N OF THE ITCZ BETWEEN 31W-35W AND WITHIN 150 NM S OF THE ITCZ BETWEEN 38W-43W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH IS MOVING FROM THE CENTRAL PLAIN STATES ACROSS THE MISSISSIPPI VALLEY AND INTO THE NW GULF WATERS SUPPORTING A COLD FRONT ENTERING THE GULF AT 06/0300 UTC FROM A 1015 MB LOW OVER LAKE PONTCHARTRAIN LOUISIANA ALONG 27N92W 24N94W TO INLAND OVER MEXICO JUST S OF TUXPAN WHERE IT CONTINUES NW AS A STATIONARY FRONT ALONG THE E SLOPES OF THE SIERRA MADRE MOUNTAINS. BROKEN/OVERCAST LOW/MID CLOUDS WITH SCATTERED SHOWERS COVERS THE GULF W OF THE FRONT. A SURFACE RIDGE IS BUILDING W OF THE FRONT ANCHORED BY 1036 MB HIGH OVER CENTRAL PLAIN STATES. A SURFACE RIDGE ANCHORED IN THE W ATLC EXTENDS AN AXIS ACROSS FLORIDA NEAR TAMPA INTO THE E GULF TO 25N90W GIVING THE E GULF SOUTHERLY RETURN FLOW WITH ISOLATED SHOWERS WITHIN 90 NM OF LINE FROM 24N85W TO OVER THE N GULF COAST NEAR FORT WALTON BEACH FLORIDA. THE REMAINDER OF THE UPPER LEVELS ARE DOMINATED BY AN UPPER RIDGE WITH AN AXIS EXTENDING FROM THE YUCATAN PENINSULA TO ACROSS S FLORIDA COVERING INTO THE W ATLC. COLD FRONT WILL REACH FROM N FLORIDA TO E BAY OF CAMPECHE WED EVENING THEN MOVE SE OF THE GULF LATE THU. CARIBBEAN SEA... A NARROW UPPER TROUGH AXIS EXTENDS FROM THE CENTRAL ATLC THROUGH THE MONA PASSAGE ALONG 13N74W TO COSTA RICA NEAR 10N83W. VERY STRONG SUBSIDENCE AND DRY STABLE AIR ARE W OF A LINE FROM THE N LEEWARD ISLANDS NEAR 17N63W TO COLOMBIA NEAR 12N71W WHILE MOIST TROPICAL AIR IS TO THE E OF THIS LINE. SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS ARE IN THE MOIST SECTOR OF THE CARIBBEAN WHILE THE REMAINDER OF THE CARIBBEAN IS UNDER MOSTLY FAIR CONDITIONS AGAIN TONIGHT. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 10N75W INTO THE E PACIFIC REGION OVER COSTA RICA NEAR 11N84W WITH ISOLATED SHOWERS/THUNDERSTORMS WITHIN 30 NM ALONG THE COAST OF COLOMBIA AND E PANAMA. RAINS CONTINUE TO TRAIN ACROSS THE LEEWARD ISLANDS CONTINUING THE POTENTIAL FOR FLOODING ESPECIALLY IN MOUNTAINOUS REGIONS. SHOWERS/THUNDERSTORMS OVER THE E CARIBBEAN WILL PERSIST TONIGHT. ATLANTIC OCEAN... THE UPPER RIDGE FROM THE GULF OF MEXICO EXTENDS AN AXIS ACROSS S FLORIDA INTO THE W ATLC TO BEYOND 32N72W COVERING THE W ATLC W OF 70W. A SURFACE RIDGE REMAINS OVER THE W ATLC S OF 30N W OF 65W AND N OF 30N W OF 56W WITH THE AXIS EXTENDING THROUGH 32N76W TO ACROSS FLORIDA NEAR DAYTONA BEACH. A NARROW UPPER TROUGH IN THE CENTRAL ATLC EXTENDS FROM AN ILL-DEFINED UPPER LOW NEAR 27N62W INTO THE CENTRAL CARIBBEAN THROUGH THE MONA PASSAGE SUPPORTING A SURFACE TROUGH EXTENDING FROM 27N64W TO 21N63W WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 22N-27N BETWEEN 60W-66W. MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR COVERS THE REMAINDER OF THE W ATLC W OF 60W GIVING THE AREA FAIR WEATHER AGAIN TONIGHT. A BROAD UPPER RIDGE IS TO THE E OF THE UPPER TROUGH EXTENDING FROM NEAR 12N49W TO 30N50W. A SURFACE TROUGH IS EMBEDDED BENEATH THIS UPPER RIDGE ANALYZED FROM 28N54W 23N54W TO JUST E OF THE LESSER ANTILLES NEAR 14N60W. THE UPPER RIDGE IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 16N-27N BETWEEN 44W-60W AND FROM 14N-20N BETWEEN 60W-63W. A SURFACE RIDGE DOMINATES THE E ATLC ANCHORED BY A 1034 MB HIGH OVER THE AZORES. SURFACE RIDGE OVER THE NW ATLC WILL WEAKEN AND SHIFT SE THROUGH WED. A COLD FRONT WILL MOVE OFF THE SE COAST THU THEN WEAKEN INTO TROUGH OVER THE W ATLC FRI. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW