000 AXNT20 KNHC 101720 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU SEP 10 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 1645 UTC. ...SPECIAL FEATURES... TROPICAL STORM HENRI IS CENTERED NEAR 32.6N 60.8W AT 10/1500 UTC OR ABOUT 205 NM E OF BERMUDA MOVING N AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 40 KT. SCATTERED MODERATE CONVECTION IS FROM 29N TO 35N BETWEEN 54W AND 61W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS EMERGING OFF THE COAST OF W AFRICA TODAY WITH AN AXIS THAT EXTENDS FROM 18N15W TO 09N15W. A MODERATE SURGE OF MOISTURE IS INDICATED IN SSMI TPW SEVERAL HUNDRED MILES AHEAD OF THE WAVE. SCATTERED MODERATE CONVECTION IS FROM 05N TO 18N BETWEEN THE AFRICAN COAST AND 22W. A TROPICAL WAVE OVER THE CENTRAL ATLC HAS AN AXIS THAT EXTENDS FROM 19N31W TO 10N34W MOVING W AT 15 KT. THE WAVE COINCIDES WITH A RELATIVELY SHARP 700 MB TROUGH AND A MAXIMUM IN 850 MB RELATIVE VORTICITY. THE WAVE IS EMBEDDED IN A BROAD AREA OF MODERATE MOISTURE. SCATTERED MODERATE CONVECTION IS FROM 07N TO 14N BETWEEN 30W AND 40W. A TROPICAL WAVE...THE REMNANTS OF GRACE...EXTENDS OVER THE CENTRAL ATLC FROM 19N56W THROUGH A 1011 MB LOW NEAR 15N56W...TO 11N57W...MOVING W AT 20 KT. SSMI TPW INDICATES A POLEWARD SURGE IN MOISTURE ALONG THE WAVE AXIS. SCATTERED MODERATE CONVECTION IS FROM 11N TO 17N BETWEEN 53W AND 63W. A TROPICAL WAVE OVER THE EASTERN CARIBBEAN HAS AN AXIS THAT EXTENDS FROM 18N68W TO 10N69W MOVING W AT 20 KT. SSMI TPW SHOWS THIS WAVE IS AT THE LEADING EDGE OF A LOW AMPLITUDE SURGE OF MOISTURE. NO DEEP CONVECTION IS CURRENTLY OCCURRING WITH THIS WAVE. A TROPICAL WAVE OVER THE WESTERN CARIBBEAN HAS AN AXIS THAT EXTENDS FROM 17N82W TO 09N83W...MOVING W AT 20 TO 25 KT. DEEP MOISTURE IS NOTED S OF 14N WITH THE EASTERN EXTENSION OF THE EASTERN PAC MONSOON TROUGH ALONG THE SOUTHERN EDGE OF THE WAVE. SCATTERED MODERATE/STRONG CONVECTION IS S OF 14N W OF 78W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO 10N33W WHERE THE ITCZ BEGINS AND CONTINUES TO 09N45W TO 13N54W. OTHER THAN CONVECTION ASSOCIATED WITH THE TROPICAL WAVE EMERGING OFF THE COAST OF AFRICA AND THE TROPICAL WAVE OVER THE EASTERN ATLC NEAR 31W/33W...ISOLATED MODERATE CONVECTION IS WITHIN 125 NM OF THE MONSOON TROUGH AND ITCZ AXIS. ...DISCUSSION... GULF OF MEXICO... A MID TO UPPER LEVEL TROUGH EXTENDS FROM THE OHIO VALLEY TO THE N CENTRAL GULF. SHORTWAVE ENERGY MOVING ACROSS THE NW GULF TOWARD THE BASE OF THE TROUGH IS SUPPORTING SCATTERED THUNDERSTORMS FROM 27N TO 30N BETWEEN 90W AND 98W. DOWNSTREAM OF THE TROUGH...ASCENT IS INTERACTING WITH A MODERATELY MOIST ATMOSPHERE TO SUPPORT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM 24N TO 30N E OF 85W. THE DIURNAL SURFACE TROUGH OVER THE SW GULF EXTENDS FROM 22N95W TO 18N95W MOVING W. SCATTERED THUNDERSTORMS ARE WITHIN 50 NM OF THE TROUGH AXIS. A 1016 MB HIGH CENTERED NEAR 27N87W SUPPORTS MODERATE S TO SE WINDS OVER THE WESTERN GULF WITH ANTICYCLONIC GENTLE TO MODERATE WINDS OVER THE EASTERN GULF. CONVECTION WILL CONTINUE THROUGH TONIGHT OVER THE NORTHERN GULF ASSOCIATED WITH THE SHORTWAVE ENERGY MOVING EAST. ADDITIONAL SHORTWAVE ENERGY WILL ENHANCE CONVECTION ONCE AGAIN OVER THE NW GULF ON FRIDAY. CARIBBEAN SEA... UPPER LEVEL RIDGING IS CENTERED OVER THE W CARIBBEAN NEAR 18N86W. UPPER LEVEL TROUGHING EXTENDS FROM THE W ATLC TO PUERTO RICO SW ACROSS THE CARIBBEAN TO NEAR 11N72W. THE UPPER RIDGE IS PROVIDING A DIFFLUENT ENVIRONMENT THAT IS HELPING TO ENHANCE CONVECTION ASSOCIATED WITH A WESTERN CARIBBEAN TROPICAL WAVE. ANOTHER TROPICAL WAVE OS LOCATED OVER THE EASTERN CARIBBEAN. PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS ON THESE TWO WAVES. ASCENT ON THE EASTERN SIDE OF THE UPPER TROUGH ALONG WITH MODERATE MOISTURE SUPPORTS ISOLATED MODERATE CONVECTION OVER AND WITHIN 150 NM W OF THE LESSER ANTILLES S OF 14N. MODERATE TO FRESH TRADE WINDS ARE S OF 16N BETWEEN 71W AND 78W OVER THE CENTRAL CARIBBEAN. GENTLE TO MODERATE TRADE WINDS ARE ELSEWHERE OVER THE CARIBBEAN. OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE OVER THE SW CARIBBEAN. A TROPICAL WAVE WITH THE REMNANTS OF GRACE WILL CROSS THE LEEWARD ISLANDS TONIGHT WITH CONVECTION. ...HISPANIOLA... SHALLOW MOISTURE OVER THE ISLAND WILL SUPPORT ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING. GENERALLY FAIR WEATHER IS EXPECTED OVERNIGHT TONIGHT. A TROPICAL WAVE...INCLUDING THE REMNANTS OF GRACE...WILL APPROACH THE ISLAND FRIDAY NIGHT. THIS WILL LIKELY ENHANCE SHOWER AND THUNDERSTORM ACTIVITY BEGINNING FRIDAY NIGHT...LASTING THROUGH SATURDAY. ATLANTIC OCEAN... AN UPPER TROUGH IS OVER THE OHIO VALLEY WITH SHORTWAVE ENERGY MOVING AROUND THE EASTERN PERIPHERY OF THE TROUGH ALONG THE EASTERN US COAST. ONE SUCH SHORTWAVE SUPPORTS ISOLATED MODERATE CONVECTION N OF 28N BETWEEN 76W AND 79W. A 1016 MB HIGH IS CENTERED NEAR 28N74W AND IS LOCATED UNDERNEATH AN UPPER RIDGE AXIS THAT EXTENDS FROM THE WESTERN CARIBBEAN. A SHARP TROUGH ALONG 65W...DOWNSTREAM OF THE UPPER RIDGE AXIS...SUPPORTS ISOLATED MODERATE CONVECTION FROM 22N TO 29N BETWEEN 63W AND 71W. T.D. EIGHT IS JUST NORTH OF OUR AREA OF DISCUSSION WITH CONVECTION EXTENDING AS FAR S AS 28N. PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS. RIDGING OVER THE CENTRAL AND EASTERN ATLC IS SUPPORTED BY A PAIR OF HIGH CENTERS WITH A 1019 MB HIGH NEAR 25N41W AND A 1020 MB HIGH NEAR 29N26W. JUST NE OF THIS RIDGING IS A 1016 MB LOW NEAR 19N35W WITH A SURFACE TROUGH THAT EXTENDS W TO 29N48W. ISOLATED MODERATE CONVECTION IS WITHIN 175 NM N AND E OF THE LOW CENTER. THREE TROPICAL WAVES ARE OVER THE TROPICAL ATLC. PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS CONVECTION WILL PERSIST WITHIN SEVERAL HUNDRED MILES OF THE E US COAST ASSOCIATED WITH THE TROUGH OVER THE US. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO