000 AXNT20 KNHC 240003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED SEP 23 2015 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 2315 UTC. ...SPECIAL FEATURES... TROPICAL STORM IDA IS CENTERED NEAR 19.9N 46.6W AT 23/2100 UTC OR ABOUT 945 NM E OF THE NORTHERN LEEWARD ISLANDS MOVING E AT 4 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SCATTERED MODERATE TO NUMEROUS STRONG CONVECTION COVERS THE AREA FROM 18N- 21N BETWEEN 42W-47W. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 16N23W TO 9N25W MOVING W NEAR 5 KT OF THE PAST 24 HOURS. SSMI TPW INDICATES THE WAVE IS ALONG THE LEADING EDGE OF A SURGE OF MODERATE/DEEP MOISTURE. SCATTERED SHOWERS ARE WITHIN 90 NM W OF THE WAVE N OF 12N AND WITHIN 90/120 NM E OF THE WAVE N OF 14N. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 14N17W ALONG 9N23W TO 8N31W WHERE THE ITCZ BEGINS AND CONTINUES TO 8N37W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS INLAND AND WITHIN 60 NM ALONG THE COAST OF W AFRICA BETWEEN 13N-17N. SCATTERED MODERATE CONVECTION IS FROM 8N- 10N BETWEEN 17W-20W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH IS WEDGED BETWEEN A PAIR OF BROAD UPPER RIDGES...ONE ANCHORED OVER N/CENTRAL MEXICO AND ONE EXTENDING FROM THE CARIBBEAN OVER THE W ATLC. THE UPPER TROUGH EXTENDS FROM THE E CONUS INTO THE GULF OF MEXICO OVER PANAMA CITY FLORIDA TO THE NW YUCATAN PENINSULA AND OVER THE E BAY OF CAMPECHE SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 28N86W TO 24N90W. SECOND WEAKER SURFACE TROUGH EXTENDS FROM 24N87W THROUGH THE YUCATAN CHANNEL TO 19N86W. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 27N E OF 87W TO OVER S FLORIDA...CUBA...AND THROUGH THE STRAITS OF FLORIDA. ISOLATED SHOWERS/THUNDERSTORMS DOT THE REMAINDER OF THE E ATLC E OF 90W. A DIURNAL SURFACE TROUGH IS IN THE SW ALONG ALONG 94W S OF 21N WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM W OF THE TROUGH AXIS. STRONG SUBSIDENCE AND DRY STABLE AIR WITH CLEAR SKIES COVER THE REMAINDER OF THE GULF W OF 90W. WEAK SURFACE RIDGE WILL BUILD SW OVER THE N GULF THROUGH FRI. CARIBBEAN SEA... AN UPPER RIDGE EXTENDS FROM CENTRAL PANAMA ACROSS E CUBA INTO THE W ATLC COVERING THE W CARIBBEAN W OF 72W. A LARGE UPPER LOW CENTERED N OF PUERTO RICO/VIRGIN ISLANDS COVERS THE REMAINDER OF THE E CARIBBEAN. A SURFACE TROUGH EXTENDS FROM THE GULF OF MEXICO NEAR 24N87W THROUGH THE YUCATAN CHANNEL TO 19N86W. A SECOND SURFACE TROUGH IS OVER THE SW CARIBBEAN EXTENDING FROM 15N83W TO 10N82W. SCATTERED TO NUMEROUS SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 16N W OF 78W TO INLAND OVER CENTRAL AMERICA. AFTERNOON SHOWERS/THUNDERSTORMS HAVE DEVELOPED INLAND OVER PUERTO RICO... HISPANIOLA...AND CUBA THIS EVENING. THE ACTIVITY THAT IS OVER PUERTO RICO AND HISPANIOLA IS MOVING SE INTO THE INTO THE COASTAL WATERS INCLUDING THE MONA PASSAGE AND THE VIRGIN ISLANDS. ISOLATED SHOWERS/THUNDERSTORMS DOT THE NW CARIBBEAN N OF 18N W OF 80W. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN E OF 72W WITH CLEAR SKIES THIS EVENING. WEAK SURFACE RIDGE OVER THE SW ATLC WILL SUPPORT GENTLE TO MODERATE TRADE WINDS ACROSS MOST OF THE CARIBBEAN THROUGH FRI EXCEPT FOR PULSES OF FRESH TO STRONG WINDS OFF COLOMBIA AND W VENEZUELA MAINLY AT NIGHT. ...HISPANIOLA... NUMEROUS SHOWERS/SCATTERED THUNDERSTORMS ARE ACROSS THE ISLAND THIS EVENING. DAYTIME HEATING COUPLED WITH OROGRAPHIC LIFTING WILL CONTINUE TO GENERATE AFTERNOON SHOWERS/THUNDERSTORMS ACROSS THE ISLAND THU AND FRI. ATLANTIC OCEAN... A REMNANT STATIONARY FRONT EXTENDS THROUGH 32N79W TO A WEAK 1013 MB LOW NEAR 29N79W THEN CONTINUES W TO OVER FLORIDA NEAR MELBOURNE. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 31N W OF THE FRONT AND WITHIN 60 NM OF THE LOW CENTER. AN UPPER RIDGE EXTENDS FROM THE CARIBBEAN ACROSS CUBA NEAR 21N77W TO 32N74W. A SURFACE TROUGH IS OVER THE N BAHAMA ISLANDS EXTENDING FROM 28N77W TO THE N COAST OF CUBA NEAR 22N79W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 28N W OF 75W. AFTERNOON SHOWERS/THUNDERSTORMS HAVE DEVELOPED INLAND OVER CUBA ARE MOVING N WITHIN 75 NM ALONG THE COAST OF CUBA BETWEEN 75W-83W. A WEAK 1015 MB HIGH IS OVER THE W/CENTRAL ATLC NEAR 30N65W. A LARGE UPPER LOW IS CENTERED N OF PUERTO RICO/VIRGIN ISLANDS NEAR 25N66W GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 21N-29N BETWEEN 60W-72W. AN UPPER RIDGE OVER THE E ATLC S OF 30N E OF 40W IS PROVIDING DIFFLUNCE ALOFT TO GENERATE SCATTERED TO NUMEROUS SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 20N-30N BETWEEN 32W-40W. A BROAD SURFACE RIDGE COVERS THE E ATLC N OF 30N E OF 50W ANCHORED BY A 1023 MB HIGH N OF THE AZORES. W ATLC FRONT WILL STALL AND TRANSITION TO A SURFACE TROUGH THU. A WEAK SURFACE RIDGE WILL PERSIST E OF THE BAHAMAS THROUGH FRI. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW