000 AXNT20 KNHC 070557 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST WED DEC 07 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 A PORTION OF AFRICA WITH THE ITCZ AXIS ENTERING THE E TROPICAL ATLC NEAR 9N14W CONTINUING ALONG 5N23W 5N35W TO 6N47W. CLUSTERS OF SCATTERED MODERATE/ ISOLATED STRONG CONVECTION ARE FROM 2N-10N BETWEEN 32W-48W. CLUSTERS OF SCATTERED MODERATE CONVECTION DOT THE AREA WITHIN 90 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 15N-32W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH COVERS THE E CONUS FROM THE PLAIN STATES ACROSS THE MISSISSIPPI VALLEY AND OVER THE NW GULF SUPPORTING A COLD FRONT ENTERING THE GULF AT 07/0300 UTC OVER FORT WALTON BEACH FLORIDA ALONG 28N88W TO 24N92W WHERE IT BECOMES STATIONARY TO THE COAST OF S MEXICO NEAR 18N94W. BROKEN/OVERCAST LOW/MID CLOUDS WITH SCATTERED SHOWERS COVER THE AREA W OF THE FRONT WITH SKIES BEGINNING TO CLEAR ALONG THE TEXAS COAST. A SURFACE RIDGE CONTINUES TO BUILD W OF THE FRONT WITH A 1031 MB HIGH OVER NE MEXICO. SOUTHERLY FLOW IS E OF THE FRONT WITH ISOLATED SHOWERS WITHIN 120 NM E OF THE FRONT N OF 27N AND WITHIN 75 NM E OF THE FRONT BETWEEN 20N-26N. THE REMAINDER OF GULF IS DOMINATED BY AN UPPER RIDGE ANCHORED OVER THE N YUCATAN PENINSULA EXTENDING AND AXIS NE ACROSS EXTREME S FLORIDA INTO THE W ATLC. STRONG SUBSIDENCE AND DRY STABLE AIR ARE COVER THE GULF SE OF A LINE FROM APALACHICOLA BAY FLORIDA TO TUXPAN MEXICO WITH ACCOMPANYING CLEAR SKIES. SLOW MOVING COLD FRONT WILL REACH FROM FLORIDA BIG BEND TO E BAY OF CAMPECHE WED THEN MOVE SE OF THE AREA WED NIGHT. GALE FORCE WINDS ARE EXPECTED BEHIND THE FRONT IN THE SW GULF WED. SURFACE RIDGE WILL CONTINUE TO BUILD E ACROSS THE N GULF THU. CARIBBEAN SEA... A NARROW UPPER TROUGH AXIS EXTENDS FROM AN UPPER LOW N OF PUERTO RICO ALONG 16N68W THEN W TO NICARAGUA NEAR 13N83W. STRONG SUBSIDENCE AND DRY STABLE AIR COVERS ALL BUT THE FAR SE CARIBBEAN WHERE MOIST TROPICAL AIR IS SE OF LINE FROM THE LEEWARD ISLANDS NEAR 17N62W TO VENEZUELA NEAR 11N68W. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA NEAR 9N75W ALONG 10N80W INTO THE E PACIFIC REGION OVER PANAMA/COSTA RICA NEAR 9N83W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 45/60 NM ALONG THE COAST OF COLOMBIA AND E PANAMA. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE IN THE MOIST SECTOR OF THE SE CARIBBEAN WHILE THE REMAINDER OF THE CARIBBEAN IS UNDER MOSTLY FAIR CONDITIONS AGAIN TONIGHT. A COLD FRONT WILL MOVE INTO THE YUCATAN CHANNEL WED NIGHT THEN WILL STALL AND DISSIPATE OVER THE W CARIBBEAN THROUGH FRI. ATLANTIC OCEAN... THE UPPER RIDGE FROM THE GULF OF MEXICO EXTENDS AN AXIS ACROSS EXTREME S FLORIDA INTO THE W ATLC TO BEYOND 32N70W COVERING THE W ATLC W OF 70W. A SURFACE RIDGE REMAINS OVER THE W ATLC S OF 30N W OF 60W AND N OF 30N W OF 55W AND ANCHORED BY A 1025 MB HIGH 200 NM N OF BERMUDA. AN UPPER LOW IS IN THE W/CENTRAL ATLC CENTERED N OF PUERTO RICO NEAR 21N65W COVERING THE AREA BETWEEN 58W-70W AND EXTENDING A TROUGH AXIS S INTO THE CARIBBEAN WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 19N-25N BETWEEN 63W-68W. 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 SURFACE TROUGH IS ANALYZED TO THE E EXTENDING FROM 29N48W ALONG 24N50W THROUGH A 1008 MB LOW NEAR 10N55W CONTINUING S TO E OF BARBADOS NEAR 13N58W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 20N-24N BETWEEN 50W-56W. A BROAD LOW AMPLITUDE UPPER RIDGE IS TO THE E OF THE UPPER TROUGH ALONG 43W FROM 10N-30N ENHANCING THE ACTIVITY ASSOCIATED WITH THE ABOVE SURFACE TROUGH/LOW AS WELL AS CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 9N-13N BETWEEN 45W-58W. A SURFACE RIDGE DOMINATES THE E ATLC ANCHORED BY A 1035 MB HIGH JUST N OF THE AZORES AND A 1034 MB HIGH FURTHER E. SURFACE RIDGE OVER THE NW ATLC WILL WEAKEN AND MOVE SE. A COLD FRONT WILL MOVE OFF THE FLORIDA COAST WED NIGHT THEN FROM NEAR BERMUDA TO E CUBA THU NIGHT BEFORE STALLING AND WEAKENING TO A TROUGH FRI. THIS TROUGH WILL MOVE W FRI THROUGH SUN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW