000 AXNT20 KNHC 240004 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST TUE DEC 23 2014 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...SPECIAL FEATURES... ...GALE-FORCE WINDS FORECAST FOR THE GULF OF MEXICO... A COLD FRONT CURRENTLY MOVING ACROSS THE NW GULF IS FORECAST TO EXTEND FROM SOUTHERN MISSISSIPPI SW TO THE BAY OF CAMPECHE WED MORNING. A TIGHT PRESSURE GRADIENT BETWEEN THE FRONT AND A RIDGE BEHIND IT WILL SUPPORT GALE-FORCE N WINDS AND SEA HEIGHTS TO 8 FT W OF FRONT. GALE WINDS ON THE GULF ARE FORECAST THROUGH WED NIGHT. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...AND THE OFFSHORE FORECAST...MIAOFFNT4/FZNT24 KNHC...FOR MORE DETAILS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH CROSSES THE COAST OF AFRICA NEAR 05N09W AND CONTINUES OVER THE E ATLC WATERS NEAR 05N15W. THE ITCZ BEGINS NEAR 05N15W AND CONTINUES ALONG 04N30W TO 03N48W. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 04N-06N BETWEEN 18W-22W. ...DISCUSSION... GULF OF MEXICO... SOUTHWESTERLY FLOW ALOFT BETWEEN A MIDDLE-LEVEL TROUGH ALONG THE CENTRAL U.S. WITH BASE OVER CENTRAL MEXICO AND A BROAD ANTICYCLONE ANCHORED N OF HISPANIOLA CONTINUES TO ADVECT MOISTURE FROM THE EPAC ITCZ GREAT PORTIONS OF THE GULF. THE TROUGH ALOFT...SUPPORTS A COLD FRONT THAT EXTENDS FROM A 1000 MB LOW OVER SE LOUISIANA SW TO 27N95W TO 25N97W. AHEAD OF THE FRONT...S-SE WIND FLOW RANGING FROM 15-25 KT CONTINUES TO ADVECT LOW-LEVEL MOISTURE FROM THE CARIBBEAN INTO GULF...WHICH ALONG A DIFFLUENT ENVIRONMENT ALOFT SUPPORT HEAVY SHOWERS AND TSTMS N OF 27N BETWEEN 89W-92W AND N OF 28N E OF 87W. LOW PRESSURE WILL CONTINUE ACROSS THE GULF THROUGH TONIGHT...THEN SHIFTS TO THE EASTERN BASIN WED MORNING ALONG WITH THE COLD FRONT. GALE-FORCE WINDS ARE FORECAST TO BEGIN W OF THE FRONT LATER TONIGHT CONTINUING THROUGH WED NIGHT. SEE SPECIAL FEATURES ABOVE. THE COLD FRONT IS FORECAST TO EXIT THE BASIN THU MORNING. CARIBBEAN SEA... A VERY STABLE ENVIRONMENT CONSISTING OF A BROAD MIDDLE-LEVEL ANTICYCLONE ANCHORED N OF HISPANIOLA...A RIDGE AT THE UPPER- LEVELS AND DRY AIR SUBSIDENCE CONTINUES TO SUPPORT FAIR WEATHER ACROSS THE BASIN. PATCHES OF SHALLOW MOISTURE EMBEDDED IN THE TRADE WIND FLOW SUPPORT SCATTERED CLOUDINESS AND POSSIBLE ISOLATED SHOWERS ACROSS PUERTO RICO COASTAL WATERS AND DOMINICAN REPUBLIC. TRADES RANGING FROM 20-25 KT HAVE EXTENDED ACROSS THE ENTIRE BASIN EXCEPT FOR SOUTHERN COASTAL WATERS OF THE GREATER ANTILLES AND S OF 12N WHERE WINDS ARE UP TO 15 KT. FOR THE EASTERN AND WESTERN BASIN...TRADES ON THIS RANGE ARE FORECAST TO REMAIN THROUGH WED MORNING. HOWEVER...FOR THE CENTRAL CARIBBEAN WINDS OF 20-25 KT ARE FORECAST TO PREVAIL TROUGH FRIDAY NIGHT. A COLD FRONT WILL EXIT THE GULF OF MEXICO THU MORNING WITH TAIL EXTENDING FROM WESTERN CUBA SW TO BELIZE COASTAL WATERS. HISPANIOLA... A VERY STABLE ENVIRONMENT ALOFT CONTINUES TO SUPPORT FAIR WEATHER ACROSS THE ISLAND. THESE WEATHER CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THU NIGHT AS DEEP LAYER DRY AIR WILL PREDOMINATE. ATLANTIC OCEAN... SURFACE HIGH PRESSURE ANCHORED BY A PAIR OF HIGHS ON THE NW ATLC EXTENDS A RIDGE AXIS SW TO THE SW N ATLC WATERS. A WEAKNESS IN THE RIDGE IS BEING ANALYZED AS A SURFACE TROUGH ALONG 24N72W TO 18N71W WITH NO CONVECTION ASSOCIATED WITH IT. FARTHER EAST...ANOTHER SURFACE TROUGH EXTENDS FROM 22N5