000 AXNT20 KNHC 231135 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST MON DEC 23 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... AS OF 0900 UTC...AN INITIAL COLD FRONT EXTENDS FROM NEAR APALACHICOLA FLORIDA TO 23N93W TO THE MEXICAN COAST NEAR 18N93W. A SECONDARY AND STRONGER FRONT EXTENDS FROM BILOXI MISSISSIPPI TO 25N94W. THIS SECOND FRONT HAS USHERED IN WINDS OF GALE FORCE...30 TO 35 KT OVER THE SOUTHWESTERN GULF S OF 24N W OF 95W. AN EARLIER 0302 UTC ASCAT-B PASS HAS INDICATED WINDS OF 30 KT OR GREATER WITHIN 90 NM NW OF THE SECOND FRONT AND S OF 26N. GALE FORCE NORTHERLY WINDS OF 30-40 KT ARE EXPECTED TO PERSIST UNTIL LATE TUE MAINLY S OF 22N W OF 95W. PLEASE REFER TO THE LATEST NHC/TAFB HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH TRANSITIONS TO THE INTERTROPICAL CONVERGENCE ZONE NEAR THE COAST OF AFRICA NEAR 6N13W. THE ITCZ CONTINUES THROUGH 4N30W TO 2N40W TO THE COAST OF SOUTH AMERICA NEAR 0N48W. SCATTERED MODERATE CONVECTION IS WITHIN 60-120 NM N OF THE AXIS BETWEEN 25W-38W...AND IN AN AREA FROM THE EQUATOR TO 6N BETWEEN 38W-47W. ...DISCUSSION... GULF OF MEXICO... AS OF 0900 UTC...AN INITIAL COLD FRONT EXTENDS FROM NEAR APALACHICOLA FLORIDA TO 23N93W TO THE MEXICAN COAST NEAR 18N93W. A SECONDARY AND STRONGER FRONT EXTENDS FROM BILOXI MISSISSIPPI TO 25N94W. THIS SECONDARY FRONT HAS USHERED IN GALE FORCE WINDS OVER THE SW GULF. BUOYS IN THE NW GULF REPORTED NORTHERLY WINDS OF 25 TO 30 KT WITH SEAS GENERALLY 7 TO 10 FT. SOUTHERLY WINDS OF 15 TO 20 KT ARE OCCURRING OVER THE GULF N OF 27N E OF THE FRONT. COASTAL WSR-88D RADAR DATA SHOWS SCATTERED SHOWERS AND THUNDERSTORMS BETWEEN THE TWO FRONTAL BOUNDARIES WITH THE BULK OF THE ACTIVITY OCCURRING BETWEEN APALACHICOLA AND PENSACOLA FLORIDA...WITH WEAKER ACTIVITY OVER THE EXTREME SE COAST OF LOUISIANA AND MISSISSIPPI. FAIR SKIES PREVAIL ELSEWHERE OVER THE GULF SE OF THE FIRST FRONT. IN THE UPPER LEVELS...BROAD SW FLOW COVERS THE ENTIRE GULF BETWEEN AN ELONGATED ANTICYCLONE OVER THE SW N ATLC AND A SHARP TROUGH OVER THE GREAT PLAINS. THE SW FLOW ALOFT WAS ADVECTING DEEP TROPICAL MOISTURE WITHIN A NARROW 300 NM WIDE BAND TOWARD THE N-CENTRAL GULF COAST. THE COLD FRONTS ARE FORECAST TO MERGE AND SWEEP RAPIDLY SE AND EXTEND FROM TAMPA BAY FLORIDA TO THE YUCATAN PENINSULA BY LATE TONIGHT. CARIBBEAN SEA... AN EARLIER 0258 UTC ASCAT-B PASS INDICATED A BROAD SWATH OF 25- 30 KT TRADE WINDS OVER THE CARIBBEAN FROM 10N-16N BETWEEN 72W- 78W WITH THE HIGHEST WINDS...30 KT...WITHIN 90 NM OF THE COAST OF COLOMBIA. 15-20 KT TRADEWINDS WERE NOTED OVER THE REMAINDER OF THE CARIBBEAN SEA. SCATTERED LOW TOPPED SHOWERS ARE OVER HONDURAS...NICARAGUA...AND COSTA RICA. MORE SCATTERED SHOWERS ARE OVER HISPANIOLA... PUERTO RICO...AND THE LEEWARD ISLANDS. IN THE UPPER LEVELS...A LARGE UPPER LOW OVER THE TROPICAL ATLC NEAR 21N62W WAS EXPANDING ITS INFLUENCE OVER THE CARIBBEAN E OF 75W WHILE A NARROW RIDGE PREVAILED OVER THE BASIN BETWEEN 75W AND 85W. STRONG SUBSIDENCE DOMINATED THE CARIBBEAN WHILE UPPER LEVEL MOISTURE WAS ON THE INCREASE OVER THE FAR NE CARIBBEAN AND LEEWARD ISLANDS. THE UPPER LEVEL LOW IS FORECAST TO MOVE W IN TANDEM WITH A SURFACE TROUGH OVER PUERTO RICO IN THE NEXT 24 HOURS WITH AN INCREASE IN SHOWER AND THUNDERSTORM ACTIVITY OVER THE E CARIBBEAN AND THE NORTHERN LEEWARD ISLANDS. ...HISPANIOLA... SCATTERED WARM TOP SHOWERS ARE SWEEPING OVER THE HIGHER ELEVATIONS OF HISPANIOLA. IN THE UPPER LEVELS...VERY STRONG SUBSIDENCE IS SUPPRESSING THUNDERSTORM ACTIVITY. ONCE AGAIN THIS WAS REFLECTED IN VERY DRY AIR ABOVE 600 MB IN THE 00Z SAN JUAN RAOB. LITTLE CHANGE IN OVERALL CONDITIONS EXPECTED TODAY...HOWEVER THE PROXIMITY OF A LARGE UPPER LOW AND A SURFACE TROUGH OVER PUERTO RICO MAY RESULT IN SOME ADDITIONAL ACTIVITY MON NIGHT AND TUE. ATLANTIC OCEAN... A STATIONARY 1034 MB HIGH IS CENTERED OVER THE W ATLANTIC NEAR 35N51W PRODUCING FAIR WEATHER OVER THE BAHAMAS AND W ATLANTIC. ASSOCIATED RIDGE EXTENDS EASTWARD OVER THE SUBTROPICAL ATLC ALONG 31N TO THE NW COAST OF AFRICA. IN THE TROPICS...A SURFACE TROUGH IS E OF THE LESSER ANTILLES AND WAS RELOCATED SLIGHTLY E AND CURRENTLY EXTENDS FROM 19N54W TO 09N55W MOVING W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE OCCURRING OVER THE NORTHERN PORTION OF THE TROUGH AND ENHANCED BY AN UPPER LOW NEAR 21N62W. ACTIVITY WAS GENERALLY FROM 17N TO 21N BETWEEN 53W AND 62W. ELSEWHERE...UPPER LEVEL DIFFLUENCE OVER THE CANARY ISLANDS ARE ENHANCING SHOWERS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ COBB