000 AXNT20 KNHC 042351 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT SEP 04 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 2315 UTC. ...SPECIAL FEATURES... TROPICAL STORM EARL IS CENTERED NEAR 49.4N 60.4W AT 05/0000 UTC OR ABOUT 50 NM SSW OF CAPE WHITTLE QUEBEC MOVING NNE AT 39 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 966 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. NUMEROUS SHOWERS ARE ACROSS PORTIONS OF CANADA FROM 49N-57N BETWEEN 51W-76W. 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. A 1007 MB LOW...REMNANT OF GASTON...IS E OF THE LESSER ANTILLES NEAR 17N47W MOVING WNW NEAR 10 KT. SATELLITE IMAGERY INDICATES A CURVED BAND SWIRLING AROUND THE WRN SEMICIRCLE FEEDING INTO THE LOW. SCATTERED MODERATE CONVECTION IS ASSOCIATED WITH THIS BAND FROM 17N-19N BETWEEN 45W-50W. ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR RE-DEVELOPMENT OF THIS SYSTEM AND A TROPICAL DEPRESSION COULD RE-FORM IN THIS AREA AT ANY TIME. A BROAD AREA OF LOW PRESSURE IS ACROSS THE SW GULF WHERE A SURFACE TROUGH IS ANALYZED ALONG 27N89W 24N93W 20N94W. SHOWERS/THUNDERSTORMS ARE WITHIN 90 NM EITHER SIDE OF THE TROUGH AXIS WITH STRONGER ACTIVITY COVERING MUCH OF THE BAY OF CAMPECHE. THE ACTIVITY HAS GAINED SOME SLIGHT ORGANIZATION AND SOME DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS. ...TROPICAL WAVES... TROPICAL WAVE IS OVER INTERIOR W AFRICA ALONG 14N7W 5N8W MOVING W NEAR 10 KT. SATELLITE IMAGERY INDICATES CYCLONIC FLOW NEAR THE WAVE AXIS CONCENTRATED NEAR A 1009 MB LOW ALONG AND THE AXIS NEAR 8N. HOVMOLLER DIAGRAM EXAMINATION AND UPPER AIR TIME-SECTION ANALYSES INDICATE THIS WAVE PASSED NIAMEY NIGER AROUND 03/2100 UTC. SCATTERED MODERATE/STRONG CONVECTION IS W OF THE WAVE AXIS FROM 6N-13N BETWEEN 9W-15W. TROPICAL WAVE EXTENDS JUST E OF THE CAPE VERDE ISLANDS ALONG 20N19W 14N23W 8N26W MOVING W 5-10 KT. THE WAVE IS EMBEDDED WITHIN A BROAD LOW-LEVEL CYCLONIC GYRE WITH SW MONSOONAL FLOW E OF THE WAVE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS W OF THE WAVE AXIS FROM 12N-15N BETWEEN 24W-27W. ...ITCZ... A MONSOONAL TROUGH AXIS EXTENDS ALONG 7N28W 8N36W. THE ITCZ AXIS BEGINS W OF THE TROUGH ALONG 11N41W 9N50W 8N59W 6N66W. SCATTERED MODERATE/STRONG CONVECTION IS NEAR THE TROUGH FROM 3N-9N BETWEEN 27W-38W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 6N-9N BETWEEN 43W-46W. ...DISCUSSION... GULF OF MEXICO... A LONGWAVE UPPER LEVEL TROUGH COVERING MUCH OF THE ERN CONUS DIGS SWD ACROSS THE NRN GULF OF MEXICO SUPPORTING A STATIONARY FRONT LINING THE NE GULF COAST FROM S OF ERN LOUISIANA NEAR 29N90W ACROSS THE FLORIDA PANHANDLE NEAR 31N84W CONTINUING NE ACROSS GEORGIA. A SHORTWAVE UPPER LEVEL TROUGH EXTENDS OFF THE LONGWAVE S OF LOUISIANA EXTENDING TO THE YUCATAN PENINSULA SUPPORTING A SURFACE TROUGH EXTENDING ALONG 27N89W 24N93W 20N94W. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. A SECOND SURFACE TROUGH IS NW OF THIS TROUGH PARALLELING THE TEXAS COASTLINE ALONG 28N93W TO 25N97W. THE COMBINATION OF SURFACE CONVERGENCE NEAR ALL THESE FEATURES ALONG WITH DIFFLUENCE ALOFT AROUND THE UPPER LEVEL TROUGH IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE CENTRAL AND WRN GULF S OF 28N BETWEEN 87W-100W. AN UPPER LEVEL RIDGE IS OVER THE FAR SW GULF CENTERED NEAR 19N94W. A SECOND UPPER LEVEL RIDGE IS OVER THE FAR SE GULF CENTERED OVER THE STRAITS OF FLORIDA NEAR 24N82W. EXPECT CONTINUED SHOWER ACTIVITY ACROSS THE SW GULF OVER THE NEXT 24 HRS WITH POSSIBLE CYCLOGENESIS IN THE SW GULF NEAR THE SURFACE TROUGH. AS MENTIONED BEFORE...SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS ON THIS TROUGH. CARIBBEAN SEA... MAINLY NE FLOW ALOFT COVERS THE WRN CARIBBEAN AROUND AN UPPER LEVEL RIDGE CENTERED OVER THE STRAITS OF FLORIDA. THIS IS PROVIDING AN AREA OF DIFFLUENCE ALOFT ENHANCING CONVECTION NEAR A SURFACE TROUGH ANALYZED IN THE SW CARIBBEAN ALONG 14N82W TO NRN COLOMBIA NEAR 9N76W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 90 NM EITHER SIDE OF THE TROUGH AXIS. SCATTERED MODERATE CONVECTION IS ALSO S OF JAMAICA FROM 15N-18N BETWEEN 76W-80W. SHOWERS/THUNDERSTORMS AREA ALSO ACROSS MUCH OF CUBA DUE TO THE COMBINATION OF DAYTIME HEATING AND INSTABILITY. THE ERN CARIBBEAN IS EXPERIENCING MOSTLY FAIR CONDITIONS UNDER THE INFLUENCE OF DRY AIR ALOFT AROUND AN UPPER LEVEL TROUGH CENTERED S OF THE VIRGIN ISLANDS NEAR 17N65W. EXPECT CONTINUED SHOWER ACTIVITY ACROSS THE WRN CARIBBEAN DUE TO ENHANCED MOISTURE ASSOCIATED WITH THE SURFACE TROUGH IN THE SW CARIBBEAN. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE COVERS THE SW ATLC CENTERED OVER THE STRAITS OF FLORIDA NEAR 24N82W SUPPORTING A SURFACE RIDGE ANCHORED BY A 1018 MB HIGH NEAR 26N68W. MODERATE MOISTURE IS ACROSS THE AREA SUPPORTING WIDELY ISOLATED SHOWERS/THUNDERSTORMS S OF 29N W OF 64W. FARTHER E...SURFACE RIDGING DOMINATES ANCHORED BY A PAIR OF 1021 MB HIGHS CENTERED NEAR 33N41W AND 34N30W PROVIDING MOSTLY FAIR WEATHER ACROSS THE CENTRAL AND ERN ATLC N OF 20N. ALOFT...AN UPPER LEVEL TROUGH IS E OF THE UPPER RIDGE CENTERED S OF THE VIRGIN ISLANDS. AN UPPER LEVEL RIDGE COVERS MUCH OF THE CENTRAL ATLC CENTERED NEAR 22N37W. A SHORTWAVE UPPER LEVEL TROUGH COVERS THE FAR E ATLC EXTENDING FROM THE CANARY ISLANDS TO THE CAPE VERDE ISLANDS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON