000 AXNT20 KNHC 132341 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU MAR 13 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 2200 UTC. ...SPECIAL FEATURES... A COLD FRONT EXTENDS FROM 32N68W THROUGH THE CENTRAL BAHAMAS... NORTHERN CUBA AND THE YUCATAN CHANNEL TO THE NORTHERN YUCATAN PENINSULA. GALE FORCE SW WINDS LIE N OF 30N WITHIN 180 NM EAST OF THE FRONT BUT ARE EXPECTED TO DIMINISH BELOW GALE FORCE BY 0000 UTC. SEE THE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/ FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 05N08W TO 02N15W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 02N15W TO THE EQUATOR AT 31W. ISOLATED MODERATE CONVECTION IS SOUTH OF 04N BETWEEN 20W-30W WHILE SCATTERED MODERATE CONVECTION LIES SOUTH OF 02N BETWEEN 30W-40W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY SHOWS THE VIGOROUS UPPER LEVEL TROUGH THAT BROUGHT A STRONG COLD FRONT TROUGH THE GULF OF MEXICO HAS PUSHED EASTWARD ALONG THE U.S. EASTERN SEABOARD. THE COLD FRONT WAS ANALYZED ACROSS THE YUCATAN CHANNEL TO THE FAR NORTHERN YUCATAN PENINSULA AT 1800 UTC. THE STRONG WINDS THAT ACCOMPANIED THE FRONT AREA DIMINISHING. A FRESH TO STRONG NORTH TO NORTHEAST BREEZE IS CONFINED TO THE AREA EAST OF 93W AND IS EXPECTED TO DIMINISH BY FRI AFTERNOON AS THE TROUGH AND COLD FRONT PULL FARTHER AWAY FROM THE AREA. 1027 MB HIGH PRES CENTERED OVER CENTRAL LOUISIANA IS DRIVING THE SURFACE WINDS...WITH SOUTHEASTERLY RETURN FLOW NOW FOUND OVER THE NORTHWESTERN GULF. FARTHER SOUTH...VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW SHALLOW CLOUDS BANKED AGAINST THE MOUNTAINS SOUTH AND WEST OF TAMPICO MEXICO. THERE IS NO SIGNIFICANT PRECIPITATION OVER THE GULF AT THIS TIME. THIS HIGH PRES IS FORECAST TO SLIDE EASTWARD ALONG 30N/31N THROUGH FRIDAY WITH SOUTHERLY RETURN FLOW EXPANDING EASTWARD INTO THE CENTRAL GULF INTO THE UPCOMING WEEKEND. CARIBBEAN SEA... THE AFOREMENTIONED COLD FRONT ASSOCIATED WITH THE VIGOROUS UPPER LEVEL TROUGH TO THE NORTH HAS MADE ITS WAY TO THE YUCATAN CHANNEL. A PRE-FRONTAL SURFACE TROUGH LIES AHEAD OF IT FROM CENTRAL CUBA TO THE COAST NEAR THE BORDER OF BELIZE AND MEXICO. SHOWERS PRIMARILY LIE WITHIN 60 NM EAST OF THE FRONT AS WELL AS BETWEEN THE FRONT AND TROUGH OVER THE NW CARIBBEAN...WITH ISOLATED THUNDERSTORMS FOUND OVER CENTRAL CUBA. ISOLATED SHOWERS AND THUNDERSTORMS ALSO CAN BE FOUND FARTHER SOUTH IN THE VICINITY OF THE GULF OF HONDURAS. THE TROUGH AND COLD FRONT ARE EXPECTED TO MERGE OVERNIGHT TONIGHT...WITH THE FRONT STRETCHING FROM THE WINDWARD PASSAGE THE BELIZE FRI NIGHT AND DISSIPATING BY SAT NIGHT. OTHERWISE...THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF A MIDDLE TO UPPER LEVEL RIDGE STEMMING FROM AN ANTICYCLONE NEAR 13N76W. WATER VAPOR IMAGERY INDICATES VERY DRY AIR WITH SUBSIDENCE PREVAILING GENERALLY SOUTH OF 18N E OF 80W. THE ONLY SIGNIFICANT AREAS OF ISOLATED SHOWERS ARE FOUND FROM WITHIN 120 NM SW OF THE SW TIP OF HAITI AND OVER THE EASTERN CARIBBEAN WITHIN 90 NM EITHER SIDE OF A LINE FROM 17N69W TO 11N63W. TRADE WINDS ARE RELATIVELY WEAK ACROSS THE CARIBBEAN AS HIGH PRES TO THE NE IS BEING FORCED AWAY FROM THE AREA BY THE FRONTAL BOUNDARY MOVING ACROSS THE YUCATAN CHANNEL...DIMINISHING THE PRES GRADIENT ACROSS THE AREA. ...HISPANIOLA... VISIBLE SATELLITE IMAGERY SHOWS SCATTERED SHOWERS ARE CLUSTERED CLOSE TO THE MOUNTAIN RANGES OVER HISPANIOLA...WITH LIGHT WINDS PREVENTING THEM FROM STRAYING FAR FROM THE AREA OF GREATEST OROGRAPHIC ENHANCEMENT. ELSEWHERE...MOSTLY CLEAR SKIES AND FAIR CONDITIONS ARE NOTED. THE FRONTAL BOUNDARY MOVING ACROSS THE SW NORTH ATLC AND THROUGH THE YUCATAN CHANNEL WILL BEGIN TO IMPACT HISPANIOLA FRI AS MOISTURE POOLED AHEAD OF THE FRONT INCREASES THE PROBABILITY OF PRECIPITATION FRI INTO SAT. THE FRONT IS EXPECTED TO WEAKEN AS IT REACHES THE WINDWARD PASSAGE FRI EVENING AND DISSIPATE OVER NORTHERN HISPANIOLA BY SAT EVENING. ATLANTIC OCEAN... A VIGOROUS UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY MOVING OFF THE U.S. EASTERN SEABOARD. ITS ASSOCIATED COLD FRONT AT THE SURFACE EXTENDS FROM 32N68W THROUGH THE CENTRAL BAHAMAS TO NORTHERN CUBA NEAR 23N80W. GALE FORCE WINDS AHEAD OF THE FRONT N OF 30N ARE DISCUSSED IN THE SPECIAL FEATURES SECTION ABOVE. A PRE-FRONTAL SURFACE TROUGH LIES APPROXIMATELY 75 NM AHEAD OF THE FRONT SOUTH OF 25N. THIS SURFACE TROUGH IS EXPECTED TO MERGE WITH THE FRONT OVERNIGHT TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS CAN BE FOUND WITHIN 120 NM EAST OF THE FRONT NORTH OF 25N...WITH MORE ISOLATED SHOWERS AND THUNDERSTORMS FOUND SOUTH OF 25N. FARTHER EAST...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE STEMMING FROM A 1028 MB HIGH PRES CENTER NEAR 35N40W. A WEAKENING SURFACE TROUGH REMAINS EMBEDDED WITHIN THE WESTERN PERIPHERY OF THE RIDGE. THE TROUGH IS ANALYZED FROM 29N49W SW TO 23N57W. ISOLATED SHOWERS AND THUNDERSTORMS LIE WITHIN 240 NM E OF THE TROUGH FROM 27N-29N...WITH ISOLATED SHOWERS ALSO FOUND WITHIN 240 NM E OF THE TROUGH FROM 23N-25N. THIS TROUGH SHOULD WEAKEN AS IT MOVES WESTWARD TOWARD THE COLD FRONT OVER THE SW NORTH ATLC. FINALLY...ON THE EASTERN PERIPHERY OF THE RIDGE LIES A COLD FRONT THAT EXTENDS INTO THE DISCUSSION AREA NEAR 32N30W THEN SW TO 27N35W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 90 NM SOUTHEAST OF THE FRONT. THIS FRONT IS EXPECTED TO DISSIPATE OVER FORECAST WATERS FRI...POSSIBLY LEAVING A TROUGH BEHIND SAT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ SCHAUER