000 AXNT20 KNHC 171140 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU SEP 17 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1140 UTC. ...SPECIAL FEATURES... TROPICAL DEPRESSION NINE IS CENTERED NEAR 16.3N 45.3W AT 17/0900 UTC OR ABOUT 925 NM E OF THE LESSER ANTILLES AND ABOUT 1225 NM W OF THE CAPE VERDE ISLANDS MOVING NW AT 6 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 90/120 NM OF LINE FROM 13N42W TO 18N43W. SCATTERED MODERATE WITH CLUSTERS OF ISOLATED STRONG CONVECTION COVERS THE AREA WITHIN 90 NM OF LINE FROM 18N41W TO 23N38W. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. A 1008 MB LOW SW OF THE CAPE VERDE ISLANDS IS CENTERED NEAR 12N32W ALONG A TROPICAL WAVE THAT EXTENDS FROM THE LOW TO 17N MOVING W-NW 10-15 KT OVER THE PAST 24 HOURS. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 6N-14N BETWEEN 30W-39W. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE CONDUCIVE FOR A TROPICAL DEPRESSION TO DEVELOP DURING THE NEXT DAY OR TWO. THERE IS A HIGH CHANCE OF TROPICAL FORMATION OVER THE NEXT 48 HOURS. ...TROPICAL WAVES... TROPICAL WAVE IN THE CARIBBEAN EXTENDS FROM 19N75W ALONG 15N77W TO 11N79W MOVING W-SW 20-25 KT OVER THE PAST 24 HOURS. SSMI TPW INDICATES THE WAVE IS EMBEDDED WITHIN AN AREA OF DEEP MOISTURE. ACTIVITY IN THE VICINITY OF THE WAVE IS ASSOCIATED WITH UPPER TROUGH. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 19N16W ALONG 12N20W 12N27W THROUGH THE 1008 MB LOW IN THE SPECIAL FEATURES NEAR 12N32W TO 13N37W. THE ITCZ BEGINS SW OF T.D. NINE NEAR 9N50W AND CONTINUES ALONG 8N54W TO SOUTH AMERICA NEAR 9N61W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 45 NM OF LINE FROM 8N17W TO 10N20W AND WITHIN 75 NM OF LINE FROM 10N20W TO 14N24W. SCATTERED MODERATE CONVECTION IS FROM 10N-11N BETWEEN 44W-48W. THE REMAINDER OF THE CONVECTION IS ASSOCIATED WITH T.D. NINE AND THE LOW/TROPICAL WAVE IN THE SPECIAL FEATURES. ...DISCUSSION... GULF OF MEXICO... A NARROW UPPER TROUGH EXTENDS ACROSS GEORGIA/ALABAMA INTO THE GULF NEAR PENSACOLA FLORIDA ALONG THE W COAST OF THE YUCATAN PENINSULA TO 19N91W. STRONG SUBSIDENCE AND DRY STABLE AIR WITH CLEAR SKIES COVERS THE W GULF N OF 20N THIS MORNING. A SURFACE TROUGH IS OVER THE E GULF EXTENDING AT 17/0900 UTC FROM THE BIG BEND OF FLORIDA NEAR 30N84W THROUGH A WEAK 1011 MB LOW NEAR 24N86W TO 22N88W. SCATTERED TO NUMEROUS SHOWERS/ISOLATED THUNDERSTORMS ARE E OF THE SURFACE TROUGH TO OVER S FLORIDA AND THROUGH THE STRAITS OF FLORIDA FROM 23N-28N WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM W OF THE SURFACE TROUGH FROM 24N-28N. A SECOND SECOND SURFACE TROUGH IS IN THE BAY OF CAMPECHE FROM 21N91W TO THE COAST OF S MEXICO NEAR 18N95W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS INLAND AND WITHIN 30/45 NM ALONG THE IMMEDIATE COAST OF MEXICO FROM 93W- 96W. SURFACE TROUGH/LOW WILL MEANDER OVER THE E GULF TODAY THEN BECOME MORE NE/SW ORIENTED ACROSS THE E AND CENTRAL GULF FRI THROUGH THE WEEKEND. CARIBBEAN SEA... AN UPPER RIDGE ANCHORED IN THE NW CARIBBEAN NEAR 18N85W EXTENDS A RIDGE AXIS NE ACROSS CUBA NEAR 23N80W INTO THE W ATLC COVERING THE NW CARIBBEAN W OF 80W. AN UPPER TROUGH EXTENDS THROUGH THE WINDWARD PASSAGE AND OVER HAITI TO NEAR 14N81W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE W OF THE UPPER TROUGH FROM 18N-20N BETWEEN 74W-77W AND WITHIN 60/75 NM OF LINE FROM 16N79W TO THE COAST OF NICARAGUA NEAR 14N83W WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS E OF THE UPPER TROUGH WITHIN 90 NM OF LINE FROM 15N72W ACROSS THE DOMINICAN REPUBLIC TO BEYOND 20N69W. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN ALONG 10N GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 12N E OF 82W TO OVER PANAMA AND COLOMBIA. THIS IS LEAVING THE FAR E AND FAR W CARIBBEAN WITH CLEAR SKIES THIS MORNING. THE CARIBBEAN TROPICAL WAVE WILL PASS THROUGH THE W CARIBBEAN TODAY THROUGH THE WEEKEND. ...HISPANIOLA... SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE ACROSS THE DOMINICAN REPUBLIC ASSOCIATED WITH THE UPPER TROUGH THAT EXTENDS THROUGH THE WINDWARD PASSAGE AND OVER HAITI. THE UPPER TROUGH WILL CONTINUE TO SHIFT E TODAY EXTENDING FROM THE CENTRAL ATLC ACROSS HISPANIOLA FRI THEN WILL SHIFT S ON SAT. MOISTURE AND SHOWER/THUNDERSTORM ACTIVITY WILL PERSIST THROUGH SAT. ATLANTIC OCEAN... AN UPPER RIDGE EXTENDS FROM THE NW CARIBBEAN ACROSS W CUBA NEAR 23N80W ALONG 26N78W TO BEYOND 32N73W. A SURFACE RIDGE COVERS THE W ATLC N OF 26N W OF 60W ANCHORED BY A 1025 MB HIGH OVER NORTH CAROLINA/VIRGINIA. THE SURFACE TROUGH/LOW IN THE E GULF OF MEXICO IS GENERATING SCATTERED TO NUMEROUS SHOWERS/ISOLATED THUNDERSTORMS ACROSS FLORIDA INTO THE W ATLC N OF 24N W OF 75W. AN UPPER TROUGH EXTENDS FROM 24N68W THROUGH THE WINDWARD PASSAGE AND OVER HAITI INTO THE CARIBBEAN GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 23N BETWEEN 67W-74W. AN UPPER TROUGH IN THE CENTRAL ATLC NEAR 48W IS SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 30N49W TO 23N52W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90/120 NM ON BOTH SIDES OF THE SURFACE TROUGH. A SHORTWAVE UPPER TROUGH IS IN THE E/CENTRAL ATLC ALONG 36W N OF 28N SUPPORTING A WEAK 1017 MB LOW NEAR 30N36W WITH SCATTERED SHOWERS FROM 30N-31N BETWEEN 32W- 36W AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 45 NM OF LINE FORM 27N40W TO 30N42W. A WEAK 1018 MB HIGH IS IN THE E ATLC NEAR 27N27W. THE CARIBBEAN TROPICAL WAVE WILL REACH THE STRAITS OF FLORIDA TONIGHT. WEAK HIGH PRESSURE OVER THE NW ATLC WILL PERSIST THROUGH THE WEEKEND. A TROUGH WILL BUILD IN W ATLC BEGINNING TODAY BECOMING MORE NE/SW ORIENTED ACROSS NW WATERS FRI NIGHT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW