000 AXNT20 KNHC 211206 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURES... GALE FORCE WINDS ARE OCCURRING ACROSS PORTIONS OF THE SW CARIBBEAN SEA...NORTH OF THE COAST OF COLOMBIA...DUE TO STRONG PRESSURE GRADIENT BETWEEN A 1032 MB HIGH CENTERED NE OF BERMUDA NEAR 34N56W AND A 1007 MB LOW CENTERED OVER NORTH COLOMBIA NEAR 9N75W. AN EARLIER 0248 UTC ASCAT PASS SHOWED A SOLID AREA OF 25- 30 KT WINDS AND GIVEN THE LOW BIAS OF ASCAT...THERE ARE LIKELY ISOLATED AREAS OF GALE FORCE WINDS OCCURRING. GALE FORCE WINDS IN THE AREA ARE EXPECTED TO PERSIST UNTIL SUN MORNING. 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 7N12W TO 3N25W TO 3N40W TO THE COAST OF SOUTH AMERICA NEAR 1N50W. SCATTERED MODERATE CONVECTION IS WITHIN 30-45 NM OF A LINE FROM 5N20W TO 5N25W. ...DISCUSSION... GULF OF MEXICO... A 1032 MB HIGH CENTERED NE OF BERMUDA AND AN ASSOCIATED RIDGE AXIS EXTENDING WESTWARD ALONG 30N/31N IS PRODUCING 10-20 KT SE RETURN FLOW OVER THE GULF OF MEXICO. THE FLOW OF WARM AND VERY MOIST AIR OVER THE COOLER SHELF WATERS OF THE GULF OF MEXICO IS RESULTING IN AREAS OF LOW CEILINGS AND FOG MAINLY N OF 25N AND W OF 90W. ADDITIONAL PATCHES OF LOW CLOUDS WERE NOTED OVER THE NE GULF NEAR THE FLORIDA BIG BEND. OTHERWISE MOSTLY CLEAR SKIES PREVAIL. IN THE UPPER LEVELS...RIDGE AXIS EXTENDS FROM AN ANTICYCLONE OVER COLOMBIA NORTHWARD ALONG 80W. SOUTHWESTERLY FLOW ON THE BACKSIDE OF THE RIDGE AND WELL E OF A SHARP UPPER LEVEL TROUGH OVER WESTERN NEW MEXICO IS ADVECTING MID TO UPPER LEVEL MOISTURE OVER TEXAS AND THE NW GULF N OF 27N W OF 90W. STRONG SUBSIDENCE IS OVER THE REMAINDER OF THE GULF. A COLD FRONT IS FORECAST TO MOVE OFF THE TEXAS COAST LATER THIS AFTERNOON WITH A WIND SHIFT...WITH A REINFORCING SURGE SLATED TO MOVE OFF LATE SUN ACCOMPANIED BY INCREASING NORTHERLY WINDS. CARIBBEAN SEA... GALE FORCE WINDS ARE OCCURRING ACROSS PORTIONS OF THE SW CARIBBEAN SEA...NORTH OF THE COAST OF COLOMBIA. SEE SPECIAL FEATURES SECTION ABOVE. LATEST SURFACE OBSERVATIONS INDICATED 15- 20 KT TRADEWINDS OVER THE REMAINDER OF THE CARIBBEAN SEA E OF 80W...WITH LIGHTER WINDS NOTED W OF 80W. SCATTERED LOW TOPPED SHOWERS ARE OVER THE GULF OF HONDURAS...BELIZE... HONDURAS...AND NICARAGUA. MORE SCATTERED SHOWERS ARE OVER E CUBA...HISPANIOLA PUERTO RICO...AND THE LEEWARD ISLANDS. WSR-88D IMAGERY FROM SAN JUAN CONTINUED TO INDICATE SCATTERED SHOWERS SWEEPING ACROSS THE ISLAND WITH CONCENTRATED ACTIVITY ALONG THE NE COAST OF PUERTO RICO. IN THE UPPER LEVELS...A RIDGE EXTENDS SE TO NW FROM COLOMBIA ACROSS THE WESTERN CARIBBEAN SEA TO THE GULF/FLORIDA ALONG 80W. STRONG SUBSIDENCE COVERS VIRTUALLY THE ENTIRE CARIBBEAN SEA...EXCEPT OVER THE FAR NW PORTION. THE FAIRLY STABLE CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE WEEKEND. ...HISPANIOLA... SCATTERED LOW TOPPED SHOWERS ARE OVER THE DOMINICAN REPUBLIC AND HAITI IN MODERATE TO FRESH TRADEWIND FLOW. GENERALLY STABLE CONDITIONS ARE EXPECTED THROUGH THE WEEKEND AS STRONG UPPER LEVELS SUBSIDENCE PREVAILS. THE STRONG SUBSIDENCE IS REFLECTED IN VERY DRY AIR ABOVE 700 MB IN THE 00Z SAN JUAN RAOB. ATLANTIC OCEAN... A 1032 MB HIGH IS CENTERED NE OF BERMUDA NEAR 34N56W PRODUCING FAIR WEATHER OVER THE BAHAMAS AND WESTERN ATLANTIC. ANOTHER 1033 MB HIGH IS CENTERED OVER THE FAR NE ATLANTIC NEAR 37N16W. ELSEWHERE...FRESH TO STRONG NORTHEASTERLY WINDS ARE OCCURRING IN THE REGION TO WEST OF THE CAPE VERDE ISLANDS NEAR 16N28W. SCATTEROMETER PASSES MISSED THE AREA FRI NIGHT. A SURFACE TROUGH CENTERED OVER THE CENTRAL TROPICAL ATLANTIC EXTENDS FROM 19N44W TO 7N43W. SCATTERED LOW TOPPED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE TROUGH AXIS. ANOTHER SURFACE TROUGH EXTENDED FROM 31N31W TO 21N35W. A LARGE MID TO UPPER LEVEL LOW IS CENTERED OVER THE E ATLANTIC NEAR 26N33W. THIS LOW IS PRODUCING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM 23N-32N BETWEEN 25W-33W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ COBB