000 AXNT20 KNHC 221123 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 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 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...FROM 11N-13N BETWEEN 74W-78W. THE WINDS SHOULD DECREASE BELOW GALE FORCE WITHIN THE NEXT 6 TO 12 HOURS. THE WINDS ARE DUE TO A STRONG PRESSURE GRADIENT BETWEEN A 1034 MB HIGH CENTERED OVER THE NORTH CENTRAL ATLANTIC NEAR 35N51W AND BROAD LOW PRES CENTERED OVER NORTHERN COLOMBIA. A COLD FRONT EXTENDING FROM JUST E OF LAFAYETTE LOUISIANA TO JUST N OF TAMPICO MEXICO 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 OF 30 TO 40 KT BY MON MORNING OVER THE SW GULF S OF 20N W OF 95W. 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 6N20W TO 3N40W TO THE COAST OF SOUTH AMERICA NEAR 50W. SCATTERED MODERATE CONVECTION WAS INDICATED WITHIN 60 NM EITHER SIDE OF THE ITCZ BETWEEN 27W-38W. ...DISCUSSION... GULF OF MEXICO... AS OF 0900 UTC...A COLD FRONT EXTENDED FROM JUST E OF LAFAYETTE LOUISIANA TO JUST N OF TAMPICO MEXICO. S TO SE WINDS OF 20 TO 25 KT WERE OCCURRING OVER THE GULF N OF 27N E OF THE FRONT TO THE FLORIDA BIG BEND. COASTAL WSR-88D RADAR IMAGERY INDICATED STRONG THUNDERSTORMS ALONG AND WITHIN 60 NM E OF THE FRONT OVER SE LOUISIANA AND MISSISSIPPI. WIDELY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE NOTED WITHIN 180 NM NW OF THE FRONTAL BOUNDARY ALONG THE REMAINDER OF THE LOUISIANA AND UPPER TEXAS COASTS. WINDS ELSEWHERE E OF THE FRONT WERE GENERALLY FROM SE TO S AT 10 TO 15 KT. THERE WERE REPORTS OF LOW CEILINGS AND FOG OUTSIDE OF CONVECTIVE ACTIVITY OVER THE NORTHERN GULF AHEAD OF THE 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/MISSISSIPPI. 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. AN EARLIER 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...AND JUST S OF 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 HISPANIOLA MOVING W WITHIN FRESH TRADEWIND FLOW. CONDITIONS REMAIN CAPPED DESPITE THE PRESENCE OF AN UPPER LEVEL TROUGH LYING JUST S OF 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 35N51W IS PRODUCING FAIR WEATHER OVER THE BAHAMAS AND W ATLANTIC. ANOTHER 1032 MB HIGH IS CENTERED OVER THE E ATLANTIC NEAR 35N16W. A SURFACE TROUGH IS OVER THE CENTRAL ATLANTIC FROM 30N39W TO 22N41W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE WITHIN 60 NM W AND 120 NM E OF THE TROUGH. ANOTHER SURFACE TROUGH IS OVER THE TROPICAL ATLANTIC FROM 20N53W TO 11N49W MOVING W. SCATTERED SHOWERS ARE WITHIN 180 NM OF THE TROUGH AXIS...WITH AN ADDITIONAL PATCH OF SHOWERS AND THUNDERSTORMS NOTED FROM 19N-23N BETWEEN 54W-59W. OF NOTE IN THE UPPER LEVELS...A SHEARING UPPER LEVEL LOW IS CENTERED OVER THE E ATLANTIC NEAR 31N25W. A SHARPENING UPPER LEVEL TROUGH EXTENDING FROM 31N48W SW TO 22N56W WILL CLOSE OFF INTO AN UPPER LOW OVER THE NEXT 24 TO 48 HOURS AS IT MOVES TOWARD PUERTO RICO. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ COBB