000 AXNT20 KNHC 181742 CCA TWDAT TROPICAL WEATHER DISCUSSION...CORRECTED NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST TUE DEC 18 2012 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA AND IT REACHES THE WEST AFRICAN COAST NEAR THE SIERRA LEONE AND LIBERIA BORDER. THE ITCZ CONTINUES FROM 7N12W 5N26W 5N40W TO 3N47W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 200 NM S OF THE ITCZ BETWEEN 10W AND 40W. ISOLATED MODERATE CONVECTION IS WITHIN 300 NM N OF THE ITCZ BETWEEN 40W AND 50W. ...DISCUSSION... THE GULF OF MEXICO... IN THE MIDDLE TO UPPER LEVELS A DEEP LAYER TROUGH IS DIGGING THROUGH THE SOUTHEASTERN U.S.A....PASSING THROUGH THE NORTHEASTERN CORNER OF THE GULF OF MEXICO...INTO THE CENTRAL GULF WATERS...TO THE MEXICO GULF COAST NEAR 22N98W. MOSTLY WESTERLY TO SOUTHWESTERLY WINDS GREATER THAN 50 KT ARE SUPPORTING A FAST MOVING COLD FRONT IN THE SURFACE. THE COLD FRONT EXTENDS FROM NORTHWESTERN FLORIDA NEAR 30N83W THEN EXTENDS ACROSS THE CENTRAL GULF NEAR 24N90W TO 22N93W. A STATIONARY FRONT CONTINUES TO THE BAY OF CAMPECHE NEAR 19N94W. A PRE-FRONTAL TROUGH EXTENDS ACROSS CENTRAL FLORIDA FROM 30N78W 27N82W TO 25N86W. NO PRECIPITATION IS CURRENTLY ASSOCIATED WITH THE FRONT OR PRE-FRONTAL TROUGH. ANOTHER SURFACE TROUGH IS NORTHWEST OF THE YUCATAN PENINSULA FROM 23N87W 21N89W TO 19N91W. BEHIND THE COLD FRONT...A SURFACE 1017 MB HIGH IS CENTERED IN THE NORTHERN GULF COAST. WITHIN 24 HOURS...THE SURFACE HIGH IS EXPECTED TO MOVE NORTHEASTWARD TOWARD N FLORIDA. THIS WILL DISPLACE THE COLD FRONT ACROSS FLORIDA AND INTO THE WEST ATLANTIC. THE CARIBBEAN SEA... IN THE MIDDLE TO UPPER LEVELS...ANTICYCLONIC WIND FLOW COVERS THE ENTIRE CARIBBEAN. WIND MAGNITUDE UP TO 30 KT IN THE MIDDLE LEVELS AND DRY AIR SUBSIDENCE AS SHOWN BY THE WATER VAPOR SATELLITE IMAGERY DOMINATE THE REGION PROVIDING FAIR CONDITIONS. AT THE SURFACE...TRADE WINDS OF 15 KT TO 20 KT WITH A WEAK PRESSURE GRADIENT IS ACROSS THE AREA. WITHIN 24 HOURS...SIMILAR CONDITIONS AT THE SURFACE ARE EXPECTED. THE ATLANTIC OCEAN... IN THE WESTERN ATLC...THE MIDDLE TO UPPER LEVEL TROUGH MENTIONED IN THE GULF OF MEXICO SECTION ABOVE SUPPORTS THE SURFACE PREFRONTAL TROUGH PORTION THAT LIES 105 NM EAST OF THE NORTHEASTERN FLORIDA COASTLINE. SURFACE RIDGING DOMINATES THE REMAINDER OF THE WEST ATLC. ALOFT IN THE CENTRAL ATLC...A RIDGE TROUGH PATTERN WITH UPPER LEVEL WINDS GREATER THAN 50 KT CHARACTERIZES THE REGION. THE TROUGH PORTION OF THIS PATTERN SUPPORTS A SURFACE COLD FRONT THAT ENTERS THE REGION FROM 29N32W SOUTHWESTWARD TO 27N36W 24N40W. A SURFACE TROUGH CONTINUES TO 22N45W. THERE ARE SCATTERED SHOWERS WITHIN 100 NM AHEAD OF THE COLD FRONT. WEAK SURFACE RIDGING COVERS THE REST OF THE CENTRAL ATLC. IN THE EASTERN ATLC...DRY AIR SUBSIDENCE FROM ALOFT AND WEAK SURFACE RIDGING ARE PROVIDING FAIR WEATHER CONDITIONS N OF 8N E OF 25W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NAR/CW