000 AXNT20 KNHC 201131 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED APR 20 2016 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURES... ATLANTIC GALE WARNING...GALE FORCE WINDS ARE OVER THE CENTRAL ATLC N OF 25N WITHIN 180 NM SE OF A FRONT THAT EXTENDS THROUGH 32N36W TO 28N41W AND TO 24N47W WHERE IT BECOMES STATIONARY TO E OF THE LESSER ANTILLES. THESE WINDS WILL CONTINUE THROUGH 20/1800 UTC WHEN THE FRONT IS EXPECTED TO WEAKEN TO A SURFACE TROUGH. PLEASE SEE HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... A WEAK MONSOON TROUGH EXTENDS FROM MAURITANIA W AFRICA INTO THE E TROPICAL ATLC NEAR 12N16W TO NEAR 8N17W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 4N25W 3N31W 3N43W THEN INTO S AMERICA NEAR 1N50W. SCATTERED MODERATE CONVECTION IS FROM 2N-5N BETWEEN 33W- 36W WITH CLUSTERS OF SIMILAR CONVECTION FROM 1N-5N BETWEEN 42W- 49W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH EXTENDS FROM THE LOUISIANA/TEXAS BORDER ACROSS THE W GULF TO THE YUCATAN PENINSULA/YUCATAN CHANNEL. A SURFACE TROUGH IS THE SW GULF EXTENDING FROM 23N96W TO THE BAY OF CAMPECHE NEAR 19N95W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE W OF THE TROUGH TO INLAND OVER MEXICO. ISOLATED SHOWERS ARE POSSIBLE OVER THE CENTRAL GULF BETWEEN 85W- 92W. THE DIURNAL SURFACE TROUGH THAT WAS OVER THE YUCATAN PENINSULA NOW EXTENDS FROM 20N91W TO INLAND OVER S MEXICO TO SW GUATEMALA. A WEAKENING SURFACE RIDGE REMAINS OVER THE E GULF AND W ATLC ANCHORED BY A 1021 MB HIGH IN THE W ATLC. SURFACE RIDGE WILL PERSIST THROUGH THU THEN THE HIGH WILL MOVE E ALLOWING A WEAK COLD FRONT TO MOVE E THROUGH THE N AND NE GULF FRI AND SAT WITH HIGH PRESSURE MOVING INTO THE NW GULF BEHIND THE FRONT FRI NIGHT AND SAT. CARIBBEAN SEA... AN UPPER RIDGE OVER THE SOUTH AMERICA/W TROPICAL ATLC IS GIVING THE CARIBBEAN SW TO W FLOW ALOFT THIS MORNING. THE FRONT IS NOW E OF THE LESSER ANTILLES. LINGERING MOISTURE COUPLED WITH THE UPPER LEVEL FLOW ARE GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF 13N E OF 73W OVER THE LEEWARD ISLANDS TO PUERTO RICO. ISOLATED SHOWERS ARE POSSIBLE OVER ALL OF HISPANIOLA THIS MORNING. THE SURFACE RIDGE OVER THE E GULF OF MEXICO AND THE W ATLC DIPS S OVER CUBA. MODERATE TO FRESH TRADE WINDS WILL PERSIST ACROSS THE CARIBBEAN THROUGH THU NIGHT. NE WINDS ARE EXPECTED TO PULSE FRESH TO STRONG EACH NIGHT S OF HISPANIOLA AND INTO THE WINDWARD PASSAGE THROUGH THU NIGHT. W ATLC SURFACE HIGH PRES WILL SHIFT EASTWARD OVER BERMUDA FRI... THEN BECOME CENTERED NE OF THE AREA SAT DIMINISHING TRADE WINDS ACROSS MUCH OF THE CARIBBEAN. HISPANIOLA... LINGERING MOISTURE COULD GENERATE ISOLATED SHOWERS ACROSS THE ISLAND AGAIN THIS MORNING. THIS MOISTURE AND DIFFLUENCE ALOFT WILL PERSIST THROUGH THU BEFORE THE UPPER FLOW BECOMES NEAR ZONAL FROM THE WEST. MOISTURE WILL INCREASE THU EVENING FROM THE S...INCREASING THE SHOWERS INTO THE WEEKEND. AFTERNOON THUNDERSTORMS ARE POSSIBLE WITH THE DAYTIME HEATING AND OROGRAPHIC LIFTING THROUGH SAT. ATLANTIC OCEAN... A WEAKENING SURFACE RIDGE COVERS THE W ATLC W OF 65W TO OVER CUBA AND THE E GULF OF MEXICO ANCHORED BY A 1021 MB HIGH OFF THE NE FLORIDA COAST NEAR 30N78W. BROAD UPPER TROUGH COVERS THE W AND CENTRAL ATLC EXTENDING THROUGH 32N42W ALONG 26N51W TO 23N68W SUPPORTING A COLD FRONT THAT EXTENDS FROM A TRIPLE POINT N OF THE AREA THROUGH 32N36W ALONG 28N41W TO 24N47W WHERE IT BECOMES STATIONARY TO 20N55W THEN DISSIPATES TO E OF THE LESSER ANTILLES NEAR 17N61W. A RE-ENFORCING SURGE IN THE FORM OF A SURFACE TROUGH TRAILS THE FRONT EXTENDING FROM 31N46W ALONG 26N49W TO 23N55W. A BROAD UPPER RIDGE COVERS THE REMAINDER OF THE ATLC E OF THE UPPER TROUGH AND IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED TO NUMEROUS SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE FROM 17N58W 25N44W TO BEYOND 32N37W. A SURFACE RIDGE COVERS THE REMAINDER OF THE ATLC ANCHORED BY A 1020 MB HIGH NEAR 26N24W. A CENTRAL ATLC COLD FRONT WILL MOVE SLOWLY EASTWARD THROUGH WED WHILE TRANSITIONING INTO A SURFACE TROUGH. ANOTHER COLD FRONT WILL QUICKLY SWEEP SE ACROSS THE NE WATERS ON WED. HIGH PRESSURE WILL BUILD SE ACROSS THE WESTERN ATLC IN THE WAKE OF THE FRONTS THEN WEAKEN AS IT SHIFTS E ACROSS BERMUDA FRI THEN INTO THE CENTRAL ATLC SAT. A WEAK COLD FRONT WILL MOVE OFF THE SE COAST SAT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW