000 AXNT20 KNHC 272355 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU MAR 27 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 2300 UTC. ...SPECIAL FEATURES... A STRONG PRESSURE GRADIENT EXISTS ACROSS THE SW CARIBBEAN SEA BETWEEN STRONG HIGH PRESSURE CENTERED ACROSS THE SW NORTH ATLC AND LOWER PRESSURE ACROSS THE NORTHWESTERN SOUTH AMERICAN CONTINENT. WINDS ALONG THE COAST OF COLOMBIA ARE FORECAST TO CONTINUE TO PULSE TO GALE FORCE IN THE EARLY MORNING HOURS WHEN THE PRESSURE GRADIENT IS STRONGEST. GALE FORCE NE TO EAST WINDS ARE EXPECTED TO OCCUR FROM 11N-13N BETWEEN 74W-77W EARLY FRIDAY AS WELL AS EARLY SAT. 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 07N13W TO 02N22W TO 01N29W THEN ITCZ TO THE EQUATOR NEAR 36W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS SOUTH OF THE MONSOON TROUGH TO 01N BETWEEN 11W-17W. ...DISCUSSION... GULF OF MEXICO... WEST-SOUTHWESTERLY...ALMOST ZONAL...FLOW IS NOTED ALOFT OVER THE GULF OF MEXICO THIS EVENING. WATER VAPOR IMAGERY INDICATES THE SUBTROPICAL JET STREAM IS ADVECTING MOISTURE AND CLOUDINESS FROM THE EASTERN PACIFIC OVER NORTHEASTERN MEXICO ACROSS THE NORTHERN GULF TO THE FLORIDA PENINSULA. LAND-BASED RADAR IMAGERY SHOWS SHOWERS FROM 26N-28N ACROSS THE FLORIDA PENINSULA AND IN THE COASTAL WATERS AND TSTMS IN THE COASTAL WATERS OFF SE LOUISIANA. LIGHTNING DATA ALSO SHOWS TSTMS IN THE CENTRAL GULF FROM 26N-27N BETWEEN 87W-93W. THIS PRECIPITATION IS OCCURRING IN THE SOUTHWESTERN PERIPHERY OF A SURFACE RIDGE ANCHORED BY STRONG 1033 MB HIGH PRESSURE JUST OFF THE COAST OF CAPE HATTERAS. SE WINDS DOMINATE THE FLOW ACROSS THE GULF OF MEXICO...WITH FRESH TO STRONG SE WINDS FOUND N OF 24N W OF 87W AS WELL AS FROM 22N- 25N W OF 87W...INCLUDING WITHIN THE STRAITS OF FLORIDA. ASCAT PASSES FROM 1526 UTC AND 1622 UTC CONFIRM THESE CONDITIONS. THE AREA OF FRESH TO STRONG WINDS IS EXPECTED TO SHRINK WESTWARD OVER THE NEXT 24 HOURS AND DIMINISH BELOW A STRONG BREEZE BY EARLY SAT MORNING WHEN A COLD FRONT IS FORECAST TO MOVE INTO THE NORTHWESTERN GULF. A FRESH NORTHERLY BREEZE WILL GRADUALLY BUILD BEHIND THE FRONT SAT AS IT MOVES SOUTH THROUGH THE WESTERN GULF...LYING FROM THE FLORIDA PANHANDLE TO THE BAY OF CAMPECHE BY SAT AFTERNOON. CARIBBEAN SEA... WEST TO NORTHWESTERLY FLOW ALOFT IS OVER THE CARIBBEAN BASIN WITH WATER VAPOR IMAGERY INDICATING RELATIVELY DRY AIR AND A SUBSIDENT ENVIRONMENT IN PLACE THIS EVENING...ESPECIALLY SOUTH OF 15N. AT THE SURFACE...A SHEAR LINE WAS ANALYZED FROM THE NORTHWESTERN DOMINICAN REPUBLIC THROUGH HAITI AND ALONG 19N EAST OF 80W. THE 1528 UTC ASCAT PASS SHOWS FRESH TO STRONG EASTERLY WINDS IN THE LEE OF CUBA NORTH OF THE SHEAR LINE...WITH ONLY A MODERATE BREEZE AT BEST TO ITS SOUTH. WINDS WILL GRADUALLY DIMINISH TO A MODERATE BREEZE HERE THROUGH EARLY SATURDAY MORNING. ISOLATED SHOWERS ARE MAINLY OCCURRING WITHIN 120 NM SOUTH OF THE SHEAR LINE...WITH TSTMS FOUND OVER SOUTHWESTERN JAMAICA. FARTHER SOUTH...A GALE WARNING IN EFFECT FOR THE SOUTHERN CARIBBEAN WATERS OFF THE COAST OF COLOMBIA. THE STRONG PRESSURE GRADIENT CREATED BETWEEN HIGH PRESSURE CENTERED ACROSS THE SW NORTH ATLC AND LOWER PRESSURE ACROSS THE NORTHWESTERN SOUTH AMERICAN CONTINENT IS EXPECTED TO RELAX SOMEWHAT BY SATURDAY AS THE HIGH PRESSURE MOVES EASTWARD. SEE THE SPECIAL FEATURES SECTION ABOVE FOR DETAILS. ...HISPANIOLA... CURRENTLY...A SHEAR LINE IS ANALYZED FROM 20N70W TO 19N75W...FROM THE NORTHWESTERN DOMINICAN REPUBLIC THROUGH HAITI AND ALONG 19N. THIS SHEAR LINE IS PROVIDING A FOCUS FOR ISOLATED SHOWERS ACROSS MUCH OF THE ISLAND WEST OF 70W...INCLUDING THE NORTHERN ADJACENT COASTAL WATERS. SHOWERS HAVE CLUSTERED NEAR THE WINDWARD SLOPES OF THE HIGH TERRAIN THIS EVENING. THE SHEAR LINE WILL GRADUALLY DISSIPATE OVER THE NEXT 24 HOURS...WITH THE AREA OF LOW LEVEL CONVERGENCE EXPECTED TO LIFT NORTH OF THE ISLAND. SHOWERS OVER HISPANIOLA SHOULD BECOME SLIGHTLY LESS LIKELY AS THE BEST MOISTURE CONVERGENCE MOVES AWAY FROM THE ISLAND. ATLANTIC OCEAN... MOSTLY ZONAL WESTERLY FLOW IS NOTED ON WATER VAPOR IMAGERY OVER THE SW NORTH ATLC WEST OF 60W WHERE AN 80-100 KT SUBTROPICAL JET IS IN PLACE THIS EVENING. SHOWERS ARE CLUSTERED OVER THE FLORIDA PENINSULA AND IN THE COASTAL WATERS FROM 26N-28N SOUTH OF THE JET AXIS...WITH MORE ISOLATED TRADE WIND SHOWERS FOUND PRIMARILY SOUTH OF 26N. AT THE SURFACE...1033 MB HIGH PRESSURE JUST OFFSHORE OF CAPE HATTERAS...WITH A RIDGE AXIS EXTENDING SOUTHEASTWARD TO NEAR 27N60W...IS DRIVING THE EAST-SOUTHEASTERLY FLOW ACROSS THE BAHAMAS. THIS HIGH PRESSURE LIES IN THE WAKE OF A COLD FRONT STRETCHED FROM 31N51W THROUGH 20N70W TO THE NORTHWESTERN DOMINICAN REPUBLIC. VISIBLE AND INFRARED IMAGERY SHOW COLD AIR STRATOCUMULUS BEHIND THE FRONT EAST OF THE BAHAMAS. AN ASCAT-B PASS FROM 1440 UTC REVEALED FRESH TO STRONG NW WINDS BEHIND THE FRONT NORTH OF THE RIDGE AXIS AND FRESH TO STRONG NE WINDS SOUTH OF THE RIDGE AXIS EAST OF THE BAHAMAS. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT N OF 27N AND ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF THE FRONT SOUTH OF 27N. OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1033 MB HIGH CENTERED NORTH OF THE AZORES NEAR 43N31W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ SCHAUER