000 AXNT20 KNHC 081747 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE APR 08 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... A COLD FRONT IS ANALYZED FROM THE BIG BEND REGION OF FLORIDA SW TO 22N90W TO THE MEXICO COAST NEAR 18N94W. NORTH-NORTHWESTERLY WINDS CONTINUE ACROSS MUCH OF THE WESTERN GULF THIS AFTERNOON WITH GALE FORCE CONDITIONS OCCURRING ACROSS THE SW GULF S OF 20N W OF 95W. SEE 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 07N12W TO 04N17W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 04N17W TO THE EQUATOR NEAR 25W. ISOLATED MODERATE CONVECTION IS FROM 01N-04N BETWEEN 22W-29W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE EASTERN CONUS WITH AXIS EXTENDING FROM THE MID- MISSISSIPPI RIVER VALLEY NEAR 36N90W TO A BASE OVER THE NW GULF. THIS TROUGH SUPPORTS A COLD FRONT ANALYZED FROM THE BIG BEND REGION OF FLORIDA SW TO 22N90W TO THE MEXICO COAST NEAR 18N94W. MOSAIC DOPPLER RADAR AND LIGHTNING DATA...ALONG WITH VISIBLE SATELLITE IMAGERY INDICATE SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS OCCURRING WITHIN 120 TO 150 NM EAST OF THE FRONT N OF 22N. THIS CONVECTIVE ACTIVITY IS LIKELY ENHANCED BY MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE OVER THE EASTERN GULF AS SOUTHWESTERLY FLOW ALOFT CONTINUES TO ADVECT EASTERN PACIFIC MOISTURE OVER CENTRAL MEXICO AND THE GULF OF MEXICO THIS AFTERNOON. OTHERWISE...RIDGING CONTINUES TO BUILD IN ACROSS NORTHERN MEXICO AND THE WESTERN GULF OF MEXICO WEST OF THE FRONT. AS THE COLD FRONT SWEEPS EASTWARD AND CLEARS THE BASIN BY LATE TUESDAY...STRONG NORTH-NORTHWESTERLY WINDS ARE EXPECTED TO PERSIST THROUGH WEDNESDAY AFTERNOON. THEREAFTER...THE PRESSURE GRADIENT WILL RELAX SOMEWHAT AS HIGH PRESSURE DRIFTS ACROSS THE NORTHERN GULF THROUGH FRIDAY. CARIBBEAN SEA... A MIDDLE TO UPPER LEVEL RIDGE REMAINS ANCHORED OVER THE WESTERN CARIBBEAN NEAR 16N78W WITH WATER VAPOR IMAGERY INDICATING THE AIRMASS INFLUENCING THE BASIN THIS AFTERNOON IS VERY DRY AND STABLE. THIS STABILITY ALOFT CONTINUES TO IMPACT THE SURFACE CONDITIONS WITH MOSTLY FAIR SKIES AND AN OVERALL LACK OF ANY SIGNIFICANT CONVECTION. THE MOST IMPORTANT MARINE IMPACT HOWEVER REMAINS RATHER STRONG TRADE WINDS AS THE PRESSURE GRADIENT BETWEEN A SURFACE RIDGE ACROSS THE SW NORTH ATLC TO THE NORTH- NORTHEAST AND LOWER PRESSURE TO THE SOUTH ACROSS NORTHERN SOUTH AMERICA IS GENERATING E-SE WINDS E OF 80W IN THE RANGE OF 15 TO 25 KT WITH THE STRONGEST WINDS NOTED BETWEEN 67W-77W. OTHERWISE...CONDITIONS ARE EXPECTED TO MODIFY LITTLE OVER THE NEXT 12 HOURS UNTIL A COLD FRONT REACHES THE YUCATAN CHANNEL THIS EVENING INTO EARLY WEDNESDAY INTRODUCING STRONG NORTHERLY WINDS TO THE NW CARIBBEAN WEDNESDAY AND THURSDAY. ...HISPANIOLA... CURRENTLY CONDITIONS ACROSS THE ISLAND THIS AFTERNOON REMAIN RATHER TRANQUIL AND QUIET AS MIDDLE TO UPPER LEVEL DRY AND STABLE NORTHERLY FLOW PREVAILS. THIS OVERALL SYNOPTIC PATTERN IS EXPECTED TO CHANGE VERY LITTLE THROUGH LATE WEDNESDAY. THEREAFTER...AN APPROACHING FRONTAL BOUNDARY MOVING ACROSS CUBA AND THE SW NORTH ATLC TO THE NORTH WILL BEGIN TO IMPACT HISPANIOLA WITH AN INCREASE IN MOISTURE...CLOUDINESS...AND A HIGHER PROBABILITY OF PRECIPITATION DURING THE DAY ON THURSDAY. THE FRONT WILL LIKELY STALL NW OF THE ISLAND PROVIDING CONTINUED ISOLATED SHOWERS ON FRIDAY. ATLANTIC OCEAN... MUCH OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF MIDDLE TO UPPER LEVEL RIDGING ALOFT WITH THE RIDGE AXIS EXTENDING FROM THE WESTERN CARIBBEAN SEA NEAR 15N79W NE TO BEYOND 32N68W. PLENTY OF MIDDLE TO UPPER LEVEL MOISTURE AND CLOUDINESS CONTINUES TO PRECEDE AN APPROACHING UPPER LEVEL TROUGH CURRENTLY ACROSS THE EASTERN CONUS. PRE-FRONTAL SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS THE FLORIDA PENINSULA AND THE ADJACENT COASTAL AND OFFSHORE WATERS N OF 27N W OF 75W. OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC IS INFLUENCED BY A BROAD SURFACE RIDGE ANCHORED ACROSS THE CENTRAL ATLC EXTENDING A RIDGE AXIS FROM 28N50W SW TO 20N80W IN THE NW CARIBBEAN SEA. FARTHER EAST...A MIDDLE TO UPPER LEVEL LOW IS CENTERED SW OF THE IBERIAN PENINSULA NEAR 36N20W THAT SUPPORTS A WEAKENING 1014 MB LOW CENTERED NEAR 30N23W. THE FRONTAL STRUCTURE ASSOCIATED WITH THE LOW HAS DISSIPATED OVER THE PAST 12 HOURS WITH ONLY A BROAD CYCLONIC CIRCULATION REMAINING WITH NO SIGNIFICANT CONVECTION. OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A THE BROAD RIDGING PREVIOUSLY MENTIONED ANCHORED NEAR 28N50W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN