000 AXNT20 KNHC 040000 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI SEP 03 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2330 UTC. ...SPECIAL FEATURES... HURRICANE EARL IS CENTERED NEAR 39.1N 70.8W AT 04/0000 UTC ABOUT 135 NM SSW OF NANTUCKET MASSACHUSETTS MOVING NE AT 20 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 961 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. SCATTERED STRONG CONVECTION IS FROM 38N-40N BETWEEN 70W-72W. SCATTERED MODERATE CONVECTION IS ELSEWHERE FROM 38N-44N BETWEEN 68W-75W. TROPICAL DEPRESSION FIONA IS CENTERED NEAR 30.9N 65.2W AT 04/0000 UTC OR ABOUT 90 NM SSW OF BERMUDA MOVING NNE AT 14 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1013 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT3/WTNT33 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. DEEP CONVECTION NEAR FIONA HAS MOSTLY DISSIPATED. A SMALL AREA OF MODERATE CONVECTION REMAINS SW OF THE CENTER FROM 27N-29N BETWEEN 66W-69W. THE REMNANT LOW GASTON IS NEAR 15N42W MOVING W NEAR 9 KT. ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR SLOW DEVELOPMENT AND A TROPICAL DEPRESSION COULD RE-FORM AS IT MOVES WESTWARD DURING THE NEXT COUPLE OF DAYS. SCATTERED MODERATE/STRONG CONVECTION HAS INCREASED NW OF THE CENTER FROM 14N-17N BETWEEN 42W-45W. AN ACTIVE TROPICAL WAVE IS BETWEEN THE WRN COAST OF AFRICA AND THE CAPE VERDE ISLANDS ALONG 19N18W TO 9N23W. SATELLITE IMAGERY INDICATES BROAD LOW-LEVEL CYCLONIC FLOW AROUND THE WAVE AXIS CONCENTRATED NEAR A 1006 MB LOW ALONG THE AXIS NEAR 15N19W. THE WAVE IS EMBEDDED WITHIN A LARGE MAXIMUM IN DEEP LAYER MOISTURE COVERING THE AREA BETWEEN THE COAST AND 28W. A CLUSTER OF STRONG CONVECTION IS NEAR THE NRN TIP OF THE WAVE AXIS FROM 20N-23N BETWEEN 13W-17W. SIMILAR ACTIVITY IS W OF THE LOW CENTER FROM 13N-16N BETWEEN 21W-25W. ENVIRONMENTAL CONDITIONS REMAIN MARGINALLY FAVORABLE FOR DEVELOPMENT INTO A TROPICAL CYCLONE OVER THE NEXT COUPLE OF DAYS. ...TROPICAL WAVES... TROPICAL WAVE IS OFF THE WRN COAST OF AFRICA. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. ...ITCZ... ITCZ AXIS EXTENDS FROM GUINEA NEAR 11N14W ALONG 7N22W 9N32W 12N39W 6N59W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 4N-10N BETWEEN 23W-33W. ISOLATED MODERATE CONVECTION IS FROM 7N-11N BETWEEN 40W-52W. ...DISCUSSION... GULF OF MEXICO... A NARROW UPPER LEVEL SHORTWAVE TROUGH IS ACROSS THE WRN GULF OF MEXICO LYING S OF A LONGWAVE UPPER TROUGH COVERING THE ERN CONUS. THE SHORTWAVE UPPER TROUGH SUPPORTS A SURFACE TROUGH EXTENDING FROM THE SW GULF NEAR 22N95W ACROSS SRN MEXICO INTO THE GULF OF TEHUANTEPEC. A COMBINATION OF SURFACE CONVERGENCE NEAR THE TROUGH ALONG WITH DIFFLUENCE ALOFT IS SUPPORTING AN AREA OF STRONG SHOWERS/THUNDERSTORMS ACROSS THE YUCATAN PENINSULA FROM 17N-22N BETWEEN 88W-92W...AND S OF 19N BETWEEN 92W-96W. SCATTERED SHOWERS/THUNDERSTORMS ALSO EXTEND DOWN THE ERN COAST OF MEXICO. THE AREA OF DIFFLUENCE ALOFT IS ALSO SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS IN THE NE GULF FROM 24N-30N BETWEEN 84W-92W. SHOWERS/THUNDERSTORMS ARE APPROACHING THE TEXAS COASTLINE AHEAD OF COLD FRONT EXTENDING ACROSS MUCH OF THE ERN CONUS ASSOCIATED WITH THE AFOREMENTIONED LONGWAVE UPPER TROUGH. ELSEWHERE...A WEAK SURFACE RIDGE EXTENDS OVER THE NE GULF AROUND A 1017 MB HIGH S OF MOBILE ALABAMA NEAR 30N88W. ALOFT...AN UPPER LEVEL RIDGE COVERS THE ERN GULF CENTERED OVER THE NW BAHAMAS NEAR 25N78W. EXPECT SHOWERS/THUNDERSTORMS TO CONTINUE ACROSS THE SW GULF AS NEWLY FORMED TROPICAL DEPRESSION ELEVEN-E...CURRENTLY IN THE GULF OF TEHUANTEPEC NEAR 15.1N 94.3W...MOVES NW. CARIBBEAN SEA... SHOWERS/THUNDERSTORMS COVER MUCH OF CUBA DUE TO DAYTIME HEATING AND INSTABILITY. SIMILAR ACTIVITY ALSO COVERS MUCH OF HISPANIOLA. A SURFACE TROUGH IS IN THE CENTRAL CARIBBEAN EXTENDING FROM 16N75W TO INLAND COLOMBIA NEAR 10N75W. A MAXIMUM IN DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY ACCOMPANIES THE TROUGH BETWEEN 72W-80W. THIS AREA OF ENHANCED MOISTURE CAN BE TRACED BACK TO THE TROPICAL WAVE THAT DEVELOPED INTO TROPICAL STORM FIONA SEVERAL DAYS AGO. ISOLATED SHOWERS/THUNDERSTORMS ARE WITHIN 90 NM EITHER SIDE OF THE TROUGH AXIS. ALOFT...A BROAD UPPER LEVEL RIDGE CENTERED OVER THE NW BAHAMAS COVERS MUCH OF THE CENTRAL AND WRN CARIBBEAN WHILE AN UPPER LEVEL TROUGH CENTERED NE OF THE LEEWARD ISLANDS COVERS THE ERN CARIBBEAN ASSOCIATED WITH DRY AIR ALOFT. EXPECT SHOWERS/THUNDERSTORMS TO CONTINUE NEAR THE SURFACE TROUGH OVER THE CENTRAL CARIBBEAN WITH MOSTLY FAIR CONDITIONS ELSEWHERE OVER THE NEXT 24 HRS. ATLANTIC OCEAN... A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE ACROSS THE BAHAMAS AROUND A WEAK 1021 MB HIGH CENTERED NEAR 25N68W. TROPICAL STORM FIONA IS TO THE N OF THE RIDGE. SEE SPECIAL FEATURES ABOVE. MOISTURE TRAILS FROM FIONA SOUTHWARD TO THE CARIBBEAN SUPPORTING CLOUDINESS AND POSSIBLE SHOWERS/THUNDERSTORMS BETWEEN 65W-72W. ALOFT...AN UPPER LEVEL RIDGE COVERS THE FAR SW ATLC CENTERED OVER THE NW BAHAMAS NEAR 25N78W. AN UPPER LEVEL TROUGH IS TO THE E CENTERED NE OF THE LEEWARD ISLANDS NEAR 20N57W. FARTHER E...WEAK AND BROAD SURFACE RIDGING IS ACROSS THE BASIN MAINTAINING FAIR CONDITIONS N OF 20N. ALOFT...A BROAD UPPER LEVEL RIDGE COVERS THE E ATLC CENTERED NEAR 22N28W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON