000 AXNT20 KNHC 161145 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SUN DEC 16 2012 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS MOST OF AFRICA TO THE COAST OF SIERRA LEONE. THE ITCZ EXTENDS ACROSS THE E TROPICAL ATLC STARTING AT THE COAST NEAR 8N13W ALONG 4N24W 5N39W TO SOUTH AMERICA NEAR THE EQUATOR AND 40W. NUMEROUS/SCATTERED STRONG CONVECTION IS WITHIN 90 NM S OF THE ITCZ BETWEEN 30W-34W. SCATTERED MODERATE/STRONG CONVECTION COVERS THE REMAINDER OF THE AREA FROM 2N-6N BETWEEN 28W-34W...FROM 1N-8N BETWEEN 34W-40W... AND FROM THE EQUATOR TO ITCZ BETWEEN 40W-45W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 30 NM OF 6N BETWEEN 14W-19W AND FROM THE ITCZ TO 7N BETWEEN 40W-45W. A SURFACE TROUGH IS JUST N OF THE ITCZ EXTENDING FROM 13N50W TO 3N49W WITH CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 3N-9N BETWEEN 48W-53W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER RIDGE DOMINATES THE GULF ANCHORED IN THE E PACIFIC REGION AND EXTENDING A RIDGE AXIS ACROSS S MEXICO/E BAY OF CAMPECHE THROUGH THE GULF OF MEXICO ACROSS NE FLORIDA. A SURFACE RIDGE COVERS THE E GULF INTO THE W ATLC ANCHORED WELL N OF THE DISCUSSION AREA. EASTERLY SURFACE FLOW IS GENERATING ISOLATED SHOWERS OVER THE STRAITS OF FLORIDA FROM THE FLORIDA KEYS TO THE N COAST OF CUBA BETWEEN 80W-84W. SOUTHERLY RETURN FLOW OVER THE NW GULF IS GENERATING ISOLATED SHOWERS N OF 25N W OF 95W LEAVING THE REMAINDER OF THE GULF WITH TRANQUIL WEATHER THIS MORNING. LIGHT TO MODERATE SOUTHERLY RETURN FLOW IS INCREASING OVER THE NW GULF AS THE SURFACE RIDGE SLIDES E OF AREA. A COLD FRONT WILL ENTER THE NW GULF LATE TONIGHT. FRONT REACH FROM SE LOUISIANA TO SW GULF OF MEXICO MON FROM TAMPA TO EA BAY OF CAMPECHE TUE AND MOVE SE OF GULF WED. A STRONGER COLD FRONT WILL MOVE RAPIDLY ACROSS THE GULF THU. CARIBBEAN SEA... AN UPPER TROUGH COVERS THE CARIBBEAN WITH THE AXIS EXTENDING FROM THE W/CENTRAL ATLC THROUGH THE MONA PASSAGE TO THE SW CARIBBEAN. STRONG SUBSIDENCE WITH DRY STABLE AIR ALOFT CONTINUES TO DOMINATE THE CARIBBEAN. HOWEVER...A WEAK SURFACE TROUGH IS OVER THE CENTRAL CARIBBEAN EXTENDING FROM S OF HAITI NEAR 17N74W TO THE COAST OF COLOMBIA NEAR 12N75W WITH ISOLATED SHOWERS WITHIN 180 NM E OF THE TROUGH. NE TRADE WINDS ARE BANKING CLUSTERS OF SCATTERED SHOWERS INLAND AND WITHIN 90 NM ALONG THE COAST OF PANAMA TO NICARAGUA S OF 14N W OF 80W LEAVING THE REMAINDER OF THE CARIBBEAN WITH TRANQUIL WEATHER THIS MORNING. LIGHT TO MODERATE TRADE WINDS WILL PREVAIL ACROSS THE BASIN THROUGH EARLY WED THEN INCREASE OVER THE CENTRAL CARIBBEAN WED AND THU AS A STRONG SURFACE RIDGE BUILDS ACROSS THE W ATLC. ATLANTIC OCEAN... THE UPPER RIDGE OVER THE GULF OF MEXICO EXTENDS ACROSS FLORIDA INTO THE W ATLC W OF 70W. AN UPPER TROUGH COVERS THE REMAINDER OF THE W ATLC EXTENDING A TROUGH AXIS THROUGH 32N53W INTO THE CARIBBEAN THROUGH THE MONA PASSAGE AND SUPPORTING A WEAKENING SURFACE TROUGH THAT EXTENDS FROM 31N51W ALONG 25N59W TO 22N66W. A SURFACE RIDGE IS SHIFTING E OVER THE W ATLC IN W OF THE ABOVE SURFACE TROUGH AND ANCHORED WELL N OF THE DISCUSSION AREA. A SECOND SURFACE TROUGH IS IN THE E/CENTRAL ATLC EXTENDING FROM 30N44W ALONG 26N49W THROUGH A 1012 MB LOW NEAR 21N51W CONTINUING ALONG 17N51W TO 15N55W. SCATTERED SHOWERS ARE WITHIN 120 NM OF A LINE FROM 22N45W TO BEYOND 32N39W. A SURFACE RIDGE DOMINATES THE E ATLC N OF 15N E OF 40W ANCHORED BY A 1027 MB HIGH NEAR 32N20W. W ATLC SURFACE TROUGH WILL DISSIPATE LATER TODAY. A STRONG COLD FRONT WILL MOVE OFF NE FLORIDA COAST MON NIGHT AND REACH FROM 32N73W TO N BAHAMAS TUE AND INTO THE CENTRAL ATLC WED. SURFACE RIDGE WILL BUILD ACROSS THE AREA BEHIND THE FRONT TUE AND WED. ANOTHER STRONG COLD FRONT WILL MOVE OFF THE FLORIDA COAST LATE THU. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW