000 AXNT20 KNHC 220600 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST SUN DEC 22 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURES... 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 22/1200 UTC. THE WINDS ARE DUE TO A STRONG PRESSURE GRADIENT BETWEEN A 1034 MB HIGH CENTERED OVER THE NORTH CENTRAL ATLANTIC NEAR 35N53W AND A 1004 MB LOW CENTERED OVER NORTH COLOMBIA NEAR 6N74W. A COLD FRONT EXTENDING FROM LAKE CHARLES LOUISIANA TO JUST S OF BROWNSVILLE TEXAS WILL SWEEP SE AND BE REINFORCED BY A SECONDARY SURGE OF COLD AIR. THIS SECONDARY SURGE OF COLD AIR WILL RESULT IN GALE FORCE WINDS BY LATE MON OVER THE SW GULF S OF 22N W OF 92W. FOR BOTH GALE AREAS...PLEASE REFER TO THE LATEST NHC/TAFB 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 6N10W TO 4N25W TO 4N40W TO THE COAST OF SOUTH AMERICA NEAR 3N51W. ISOLATED MODERATE CONVECTION WAS INDICATED WITHIN 60-120 NM N OF THE ITCZ BETWEEN 23W-40W. ...DISCUSSION... GULF OF MEXICO... AS OF 0300 UTC...A COLD FRONT EXTENDED FROM LAKE CHARLES LOUISIANA TO JUST S OF BROWNSVILLE TEXAS. GALE FORCE WINDS WERE OCCURRING E OF THE FRONT HAVE NOW DIMINISHED TO 20 TO 30 KT. COASTAL WSR-88D IMAGERY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE OCCURRING ALONG AND WITHIN 120 NM NW OF THE FRONTAL BOUNDARY ALONG THE TEXAS AND LOUISIANA COASTS IN AN OVERRUNNING PATTERN. S TO SW RETURN AHEAD OF THE FRONT HAS NOW DIMINISHED TO 20 TO 30 KT NEAR THE FRONT. THE WINDS ELSEWHERE E OF THE FRONT WERE GENERALLY FROM SE TO S AT 15 TO LOCALLY 25 KT. THERE WERE REPORTS OF LOW CEILINGS AND FOG OUTSIDE OF CONVECTIVE ACTIVITY OVER THE NE GULF AHEAD OF THE FRONT. FAIR WEATHER IS OVER THE REMAINDER OF THE GULF E OF FRONT. IN THE UPPER LEVELS...SW FLOW ON THE BACKSIDE OF AN UPPER LEVEL ANTICYCLONE NEAR 26N75W AND ASSOCIATED RIDGE WAS ADVECTING MID TO UPPER LEVEL MOISTURE OVER THE E GULF AND WITHIN A NARROW BAND OVER LOUISIANA. SOME SUBSIDENCE WAS OVER THE REMAINDER OF THE GULF. THE COLD FRONT IS FORECAST TO SWEEP EASTWARD AND EXTEND FROM THE FLORIDA PANHANDLE TO THE BAY OF CAMPECHE BY SUN NIGHT. 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. A 0226 UTC ASCAT PASS INDICATED A LARGE AREA OF 20-25 KT TRADEWINDS OVER THE CARIBBEAN SEA FROM 11N TO 18N BETWEEN 65W AND 80W...WITH THE STRONGEST WINDS OCCURRING JUST S OF HISPANIOLA AND NEAR THE WINDWARD PASSAGE. SCATTERED WARM TOP SHOWERS ARE OVER THE GULF OF HONDURAS...BELIZE... GUATEMALA...HONDURAS...NICARAGUA...AND COSTA RICA. ADDITIONAL ACTIVITY WAS FOCUSED OVER E CUBA...JAMAICA...HISPANIOLA... PUERTO RICO...THE LEEWARD ISLANDS...AND THE WINDWARD ISLANDS. THE UPPER LEVELS...A CLOSED ANTICYCLONE NEAR 26N75W WAS PROVIDING A LOW-LATITUDE REX BLOCKING PATTERN OVER THE CARIBBEAN AND WRN ATLANTIC WITH AN ATTENDANT TROUGH AXIS EXTENDING FROM THE TROPICAL ATLC WESTWARD ACROSS THE NORTHERN LEEWARD ISLANDS...PUERTO RICO...HISPANIOLA TO E CUBA. VERY STRONG SUBSIDENCE WAS NOTED WITHIN 180-240 NM OF THE TROUGH AXIS. THE BLOCKING PATTERN OVER THE CARIBBEAN IS EXPECTED TO PERSIST OVER THE NEXT 24 HOURS...AND PERHAPS AMPLIFY BEYOND AS AN UPPER LOW IS EXPECTED TO CLOSE OFF OVER PUERTO RICO BY LATE MON. ...HISPANIOLA... SCATTERED LOW TOPPED SHOWERS ARE OVER THE HIGHER ELEVATIONS OF HISPANIOLA MOVING W WITHIN FRESH TRADEWIND FLOW. CONDITIONS REMAIN CAPPED DESPITE THE PRESENCE OF AN UPPER LEVEL TROUGH LYING ACROSS THE AREA. THE VERY STRONG SUBSIDENCE ALOFT WAS CAPTURED BY VERY DRY AIR ABOVE 650 MB IN THE 00Z SAN JUAN RAOB. LITTLE CHANGE IN THIS SCENARIO IS EXPECTED OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... A 1034 MB HIGH IS CENTERED NE OF BERMUDA NEAR 35N53W IS PRODUCING FAIR WEATHER OVER THE BAHAMAS AND W ATLANTIC. ANOTHER 1034 MB HIGH IS CENTERED OVER THE E ATLANTIC NEAR 35N16W. 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 20N50W TO 10N46W 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 $$ COBB