000 AXNT20 KNHC 051743 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT SEP 05 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM FRED AT 05/1500 UTC IS NEAR 23.4N 41.8W. FRED IS MOVING TOWARD THE WEST-NORTHWEST...OR 295 DEGREES...AT 7 KNOTS. THE MINIMUM CENTRAL PRESSURE IS 1007 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 35 KNOTS WITH GUSTS TO 45 KNOTS. ISOLATED MODERATE CONVECTION IS WITHIN 225 NM OF THE CENTER OVER THE EASTERN SEMICIRCLE. PUBLIC ADVISORIES ABOUT TROPICAL STORM FRED ARE BEING ISSUED UNDER THE AWIPS/WMO HEADER TCPAT1/WTNT31 KNHC. FORECAST/ADVISORIES ABOUT TROPICAL STORM FRED ARE BEING ISSUED UNDER THE AWIPS/WMO HEADER TCMAT1/WTNT21 KNHC. THE CENTER OF NEWLY DEVELOPED TROPICAL DEPRESSION SEVEN AT 05/1500 UTC IS NEAR 12.3N 25.2W...MOVING W...OR 280 DEGREES...AT 12 KT. THE MINIMUM CENTRAL PRESSURE IS 1008 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 30 KT WITH GUSTS TO 40 KT. NUMEROUS MODERATE CONVECTION IS FROM 11N TO 15N BETWEEN 24W AND 28W. PUBLIC ADVISORIES ABOUT TROPICAL DEPRESSION SEVEN ARE BEING ISSUED UNDER THE AWIPS/WMO HEADER TCPAT2/WTNT32 KNHC. FORECAST/ADVISORIES ABOUT TROPICAL STORM FRED ARE BEING ISSUED UNDER THE AWIPS/WMO HEADER TCMAT2/WTNT22 KNHC. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE EASTERN ATLC WITH AN AXIS EXTENDING FROM 18N32W THROUGH A 1011 MB LOW NEAR 12N32W TO 09N32W...MOVING W AT 15 KT OVER THE PAST 24 HOURS. SSMI TPW INDICATES HIGH MOISTURE MAINLY S OF 14N IN THE WAVE ENVIRONMENT. THIS WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 31W AND 38W. ISOLATED MODERATE CONVECTION IS WITHIN 125 NM OF THE LOW CENTER THAT RESIDES ALONG THE WAVE AXIS. A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AN AXIS THAT EXTENDS FROM 19N60W TO 10N61W...MOVING W AT 15 TO 20 KT OVER THE PAST 24 HOURS. THIS WAVE COINCIDES WITH A TROUGH EVIDENT AT 700 MB BETWEEN 58W AND 62W. SHALLOW MOISTURE ACCOMPANIES THE WAVE. NO DEEP CONVECTION IS NOTED WITH THE WAVE AT THIS TIME. A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN WITH AN AXIS THAT EXTENDS FROM 19N67W TO 10N69W...MOVING W AT 10 TO 15 KT OVER THE PAST 24 HOURS. THIS WAVE IS AT THE LEADING EDGE OF A SURGE OF LOW LEVEL MOISTURE. STRONG SOUTHERLY SHEAR IS IN THE WAVE ENVIRONMENT. NO DEEP CONVECTION IS NOTED WITH THE WAVE AT THIS TIME. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES OVER COASTAL SECTIONS OF AFRICA NEAR 15N17W TO TROPICAL DEPRESSION SEVEN...TO THE 1011 MB LOW PRESSURE CENTER NEAR 12N32W...TO 10N38W...WHERE THE ITCZ BEGINS AND CONTINUES TO 10N53W. OTHER THAN CONVECTION ASSOCIATED WITH THE TROPICAL DEPRESSION AND LOW... ISOLATED MODERATE CONVECTION IS WITHIN 100 NM OF THE ITCZ AXIS. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL ANTICYCLONE IS CENTERED OVER TX WHILE AN UPPER TROUGH EXTENDS FROM THE MID ATLC STATES TO FL. SHORTWAVE ENERGY ALOFT MOVING BETWEEN THESE TWO FEATURES SUPPORTS SCATTERED THUNDERSTORMS OVER THE EASTERN GULF FROM 24N TO 29N BETWEEN 83W AND 90W. A DIURNAL SURFACE TROUGH IS LOCATED OVER THE SW GULF EXTENDING FROM 22N94W TO 18N95W. NO CONVECTION IS OBSERVED WITH THIS TROUGH. A 1017 MB HIGH IS CENTERED NEAR 27N88W AND IS PROVIDING GENTLE TO MODERATE ANTICYCLONIC SURFACE WINDS OVER THE BASIN THIS AFTERNOON. OVER THE NEXT 24 HOURS WEAK SURFACE TROUGHING AND UPPER LEVEL ENERGY WILL SUPPORT CONVECTION OVER THE NE GULF. CARIBBEAN SEA... AN UPPER LOW OVER THE YUCATAN PENINSULA SUPPORTS SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM 16N TO 22N W OF 83W. UPPER LEVEL DIFFLUENCE AND THE PACIFIC MONSOON TROUGH THAT CONNECTS TO A 1008 MB LOW CENTERED NEAR 10N76W SUPPORTS SCATTERED MODERATE TO STRONG CONVECTION S OF 12N W OF 79W. A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN. PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. DRY MID TO UPPER LEVEL AIR AND STRONG DEEP LAYER SHEAR ARE INHIBITING DEEP CONVECTION OVER THE CENTRAL AND WESTERN CARIBBEAN. GENTLE TO MODERATE TRADE WINDS COVER THE MAJORITY OF THE CARIBBEAN WITH MODERATE TO FRESH TRADE WINDS S OF 16N BETWEEN 70W AND 78W. OVER THE NEXT 24 HOURS CONVECTION OVER THE NW CARIBBEAN WILL DECREASE AS THE UPPER LOW DISSIPATES. CONVECTION WILL CONTINUE OVER THE SW CARIBBEAN. ANOTHER TROPICAL WAVE WILL ENTER THE EASTERN CARIBBEAN FROM THE CENTRAL ATLC. ...HISPANIOLA... SHALLOW MOISTURE AND DAYTIME HEATING SUPPORTS ISOLATED SHOWERS AND THUNDERSTORMS OVER THE ISLAND THIS AFTERNOON. ANY THUNDERSTORMS WILL DISSIPATE LATER THIS EVENING. A TROPICAL WAVE PASSING ACROSS THE ISLAND TONIGHT MAY PROVIDE WEAK SHOWERS OVER THE ISLAND TONIGHT. ISOLATED THUNDERSTORMS WILL BE POSSIBLE AGAIN SUNDAY AFTERNOON AND EVENING. ATLANTIC OCEAN... SHORTWAVE MID TO UPPER LEVEL TROUGHS IN ZONAL FLOW OVER THE WESTERN ATLC N OF 28N SUPPORT A PAIR OF LOW PRESSURE SYSTEMS. THE WESTERNMOST LOW OF 1012 MB IS CENTERED NEAR 29N72W WITH A SURFACE TROUGH THAT EXTENDS TO THE SW TO NEAR 26N79W. SCATTERED THUNDERSTORMS ARE WITHIN 100 NM OF THE TROUGH AXIS. THE EASTERNMOST LOW IS CENTERED N OF OUR AREA OF DISCUSSION WITH A SURFACE TROUGH THAT EXTENDS SW TO 31N61W TO 26N65W. SCATTERED MODERATE CONVECTION IS FROM 26N TO 31N BETWEEN 53W AND 63W. FARTHER EAST...A THIRD SURFACE TROUGH EXTENDS INTO OUR AREA OF DISCUSSION NEAR 31N48W TO 26N50W. ISOLATED THUNDERSTORMS ARE WITHIN 125 NM E OF THE TROUGH AXIS. TROPICAL STORM FRED AND TROPICAL DEPRESSION SEVEN ARE OVER THE TROPICAL EASTERN ATLC. PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS. TWO TROPICAL WAVES ARE OVER THE TROPICAL ATLC. PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE FROM FL TO NEAR 30N70W ASSOCIATED WITH A SURFACE TROUGH. CONVECTION ASSOCIATED WITH THE TROUGH CURRENTLY ALONG 61W/65W WILL MOVE EAST WITH CONVECTION. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO