000 AXNT20 KNHC 212336 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT DEC 21 2013 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 2315 UTC. ...SPECIAL FEATURES... GALE FORCE SOUTHERLY WINDS ARE OCCURRING OVER THE NW GULF OF MEXICO IN ADVANCE OF A COLD FRONT N OF 26N AND W OF 91W...UNTIL 22/0000 UTC. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. GALE FORCE WINDS ARE OCCURRING ACROSS PORTIONS OF THE SW CARIBBEAN SEA...NORTH OF THE COAST OF COLOMBIA...FROM 11N-13N BETWEEN 74W-78W...UNTIL 22/1800 UTC. THE WINDS ARE DUE TO A STRONG PRESSURE GRADIENT BETWEEN A 1033 MB HIGH CENTERED NE OF BERMUDA NEAR 35N54W AND A 1003 MB LOW CENTERED OVER NORTH COLOMBIA NEAR 6N74W. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE AFRICAN COAST NEAR 5N10W TO 4N20W TO 4N40W TO THE COAST OF SOUTH AMERICA NEAR 3N51W. ISOLATED MODERATE CONVECTION IS FROM 3N-7N BETWEEN 17W-40W. ...DISCUSSION... GULF OF MEXICO... AS OF 2100 UTC...A COLD FRONT EXTENDS FROM N LOUISIANA TO HOUSTON TEXAS TO JUST N OF BROWNSVILLE TEXAS. GALE FORCE WINDS ARE E OF THE FRONT. SEE ABOVE. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE FRONT. SE TO S RETURN FLOW IS OVER THE GULF E OF THE FRONT WITH THE TIGHTEST SURFACE PRESSURE GRADIENT OVER THE NW GULF. FAIR WEATHER IS OVER THE REMAINDER OF THE GULF E OF FRONT. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE IS PRODUCING SW FLOW WITH UPPER LEVEL MOISTURE OVER LOUISIANA AND THE NW GULF N OF 21N W OF 92W. STRONG SUBSIDENCE IS OVER THE REMAINDER OF THE GULF. EXPECT IN 24 HOURS FOR THE COLD FRONT TO EXTEND FROM THE FLORIDA PANHANDLE TO TAMPICO MEXICO WITH CONVECTION. CARIBBEAN SEA... GALE FORCE WINDS ARE OCCURRING ACROSS PORTIONS OF THE SW CARIBBEAN SEA...NORTH OF THE COAST OF COLOMBIA. SEE ABOVE. 15-30 KT TRADEWINDS ARE OVER THE REMAINDER OF THE CARIBBEAN SEA. SCATTERED SHOWERS ARE OVER THE GULF OF HONDURAS...BELIZE... GUATEMALA...HONDURAS...NICARAGUA...AND COSTA RICA. MORE SCATTERED SHOWERS ARE OVER E CUBA...JAMAICA...HISPANIOLA... PUERTO RICO...THE LEEWARD ISLANDS...AND THE WINDWARD ISLANDS ...ALL MOVING W WITH THE TRADEWINDS. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE IS OVER THE W CARIBBEAN SEA W OF 70W. AN UPPER LEVEL TROUGH IS OVER THE E CARIBBEAN. STRONG SUBSIDENCE IS OVER ALL OF CENTRAL AMERICA...THE CARIBBEAN SEA...AND THE NORTHERN PORTION OF SOUTH AMERICA N OF 3N. EXPECT OVER THE NEXT 24 HOURS FOR ADDITIONAL SHOWERS TO BE OVER THE W CARIBBEAN AND CENTRAL AMERICA. ...HISPANIOLA... PRESENTLY SCATTERED SHOWERS ARE OVER THE HIGHER ELEVATIONS OF HISPANIOLA MOVING W WITH THE TRADEWINDS. IN THE UPPER LEVELS... VERY STRONG SUBSIDENCE IS SUPPRESSING THUNDERSTORM ACTIVITY. EXPECT SIMILAR SHOWERS OVER HISPANIOLA FOR THE NEXT 24 HOURS. ATLANTIC OCEAN... A 1033 MB HIGH IS CENTERED NE OF BERMUDA NEAR 35N54W PRODUCING FAIR WEATHER OVER THE BAHAMAS AND W ATLANTIC. THE TAIL END OF A STATIONARY FRONT IS OVER THE CENTRAL ATLANTIC FROM 36N30W TO 31N46W. ANOTHER 1033 MB HIGH IS CENTERED OVER THE E ATLANTIC NEAR 35N18W. A SURFACE TROUGH IS OVER THE CENTRAL ATLANTIC FROM 30N37W TO 22N40W. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE TROUGH. ANOTHER SURFACE TROUGH IS OVER THE TROPICAL ATLANTIC FROM 20N48W TO 10N45W MOVING W. SCATTERED SHOWERS ARE WITHIN 180 NM OF THE TROUGH AXIS. OF NOTE IN THE UPPER LEVELS...A LARGE UPPER LEVEL LOW IS CENTERED OVER THE E ATLANTIC NEAR 28N31W. SCATTERED SHOWERS ARE FROM 18N-33N BETWEEN 16W-26W TO INCLUDE THE CANARY ISLANDS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORMOSA