000 AXNT20 KNHC 041200 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURES... TROPICAL STORM EARL IS CENTERED NEAR 42.9N 65.8W AT 04/1200 UTC OR ABOUT 35 NM S OF CAPE SABLE NOVA SCOTIA MOVING NE AT 26 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 965 MB. MAXIMUM SUSTAINED WIND SPEED IS 60 KT WITH GUSTS TO 75 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. HEAVY RAIN AND POSSIBLE ISOLATED THUNDERSTORMS COVER THE AREA N OF 40N BETWEEN 63W-70W INCLUDING MAINE AND NOVA SCOTIA. THE REMNANT LOW OF GASTON IS CENTERED NEAR 15N43W ABOUT 1030 NM E OF THE LEEWARD ISLANDS MOVING W NEAR 9 KT. THE LOW LEVEL CENTER REMAINS JUST UNDER THE SE PORTION OF THE DEEP CONVECTION. LOW REMAINS EMBEDDED WITHIN AN AREA OF DEEP LAYERED MOISTURE AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY BUT WITH DRIER AIR UNDERCUTTING THE LOW. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 15N-18N BETWEEN 45W-47W. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE EASTERN MOST CAPE VERDE ISLANDS EXTENDING FROM 20N20W TO 10N26W WITH A 1008 MB LOW JUST TO THE E NEAR 16N20W. WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYERED MOISTURE AS INDICATED BY THE TOTAL PRECIPITABLE WATER IMAGERY E OF A LINE FROM 25N18W TO THE TROPICS NEAR 10N30W. SCATTERED/NUMEROUS STRONG CONVECTION IS TO THE E OF THE WAVE AXIS WITHIN 60/75 NM OF LINE FROM 17N20W TO 14N23W WITH CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 16N-20N E OF THE WAVE AXIS TO THE COAST OF MAURITANIA W AFRICA AND WITHIN 180 NM W OF THE WAVE AXIS FROM 9N-14N. ...ITCZ... ITCZ AXIS EXTENDS FROM 9N30W 8N37W 10N48W 8N61W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 3N-9N BETWEEN 24W-35W. ...DISCUSSION... GULF OF MEXICO... A NARROWING ELONGATED CUT-OFF UPPER LOW IS OVER THE W GULF EXTENDING FROM VERMILION BAY LOUISIANA S TO 23N94W. A SURFACE TROUGH IS JUST TO THE E OF THE UPPER TROUGH EXTENDING FROM 27N84W ALONG 24N90W TO THE BAY OF CAMPECHE NEAR 19N94W. AN UPPER RIDGE COVERS THE REMAINDER OF THE GULF WATERS ANCHORED IN THE FLORIDA STRAITS NEAR 25N80W AND EXTENDING AN AXIS NNW TO OVER S GEORGIA GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120 NM W OF THE TROUGH N OF 26N AND WITHIN 150 NM EITHER SIDE OF THE TROUGH S OF 25N WITH SCATTERED/NUMEROUS STRONG CONVECTION OVER THE BAY OF CAMPECHE S OF 21N BETWEEN 91W-97W. THE UPPER RIDGE IS DRAWING TROPICAL MOISTURE FROM THE CARIBBEAN ACROSS CUBA TO OVER THE SE GULF GENERATING SCATTERED SHOWERS/ THUNDERSTORMS S OF 26N TO OVER CUBA E OF 85W ACROSS THE FLORIDA KEYS AND TO JUST W OF ANDROS ISLAND IN THE BAHAMAS. A DEEP LAYERED TROUGH COVERS MOST OF THE E HALF U.S. WITH THE EXCEPTION OF THE FAR SE SUPPORTING A COLD FRONT THAT EXTENDS ACROSS S ALABAMA AND LOUISIANA TO JUST OFFSHORE NEAR LAKE CHARLES LOUISIANA THEN INLAND OVER TEXAS BETWEEN GALVESTON AND CORPUS CHRISTI. A WEAKENING PRE-FRONTAL SURFACE TROUGH EXTENDS FROM 29N92W TO INLAND OVER NE MEXICO NEAR 25N98W WITH ISOLATED SHOWERS/THUNDERSTORMS W OF SURFACE TROUGH TO THE FRONT. THE COLD FRONT IS BRINGING SOME DRIER AIR IN ITS WAKE AND WILL CONTINUE TO SLOWLY DRIFT EASTWARD WHILE THE S GULF WILL CONTINUE TO EXPERIENCE SHOWERS/THUNDERSTORMS AS T.D. ELEVEN-E CONTINUES TO MOVE OVER S MEXICO. CARIBBEAN SEA... A BROAD UPPER RIDGE ANCHORED IN THE FLORIDA STRAITS NEAR 25N80W COVERS THE CARIBBEAN W OF 75W AND EXTENDS TO OVER THE GULF OF MEXICO PROVIDING MOSTLY E TO SE UPPER LEVEL FLOW. ABUNDANCE OF TROPICAL MOISTURE ALOFT REMAINS ACROSS THE W CARIBBEAN AND COMBINED WITH DIFFLUENCE ALOFT ARE GENERATING AN AREA OF SCATTERED SHOWERS/THUNDERSTORMS FROM 14N-20N BETWEEN 79W-83W AND N OF 20N TO OVER CUBA BETWEEN 80W-84W. THE ITCZ CUTS ACROSS THE FAR SW CARIBBEAN FROM COLOMBIA NEAR 10N75W TO ACROSS COSTA RICA NEAR 11N84W INTO THE E PACIFIC REGION. A BROAD UPPER TROUGH EXTENDING OVER THE CENTRAL ATLC COVERS THE E CARIBBEAN E OF 75W TO JUST INLAND OVER N VENEZUELA. THIS IS FUNNELING IN DRY STABLE AIR ALOFT N OF 12N E OF 72W LEAVING THAT AREA REMARKABLY CLEAR THIS MORNING. HOWEVER...THE STRONG DIVERGENT FLOW TO THE W OF THE UPPER TROUGH IS GENERATING SCATTERED SHOWERS/THUNDERSTORMS S OF 15N BETWEEN 76W-79W. THE SURFACE RIDGE THAT COVERS THE W ATLC DIPS S OVER THE FAR N CARIBBEAN N OF 18N BETWEEN THE MONA PASSAGE AND THE YUCATAN CHANNEL. ATLANTIC OCEAN... TROPICAL STORM EARL IS RAPIDLY MOVING NE BUT STILL REMAINS A CONCERN FOR THE CANADIAN MARITIMES. SEE SPECIAL FEATURES ABOVE. BROAD UPPER RIDGE THAT COVERS THE GULF OF MEXICO AND THE W CARIBBEAN IS ANCHORED IN THE FLORIDA STRAITS NEAR 25N80W COVERING THE W ATLC W OF 75W. TROPICAL MOISTURE IS BEING DRAWN ACROSS CUBA AND GENERATING SCATTERED SHOWERS/THUNDERSTORMS S OF 25N ACROSS CUBA E OF 79W TO ACROSS THE FLORIDA KEYS. A SURFACE TROUGH EXTENDS FROM THE REMNANTS OF FIONA...A 1014 MB LOW NEAR 31N64W TO 21N68W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM EITHER SIDE OF THE TROUGH S OF 25N. A SURFACE RIDGE IS TO THE W OF THIS SURFACE TROUGH WITH A 1018 MB HIGH NEAR 25N70W. HOWEVER...A SECOND SURFACE TROUGH IS DEVELOPING AT 03/0900 UTC ALONG 30N68W TO 28N79W GENERATING SCATTERED SHOWERS/THUNDERSTORMS FROM 26N-29N BETWEEN 71W-79W. AN UPPER TROUGH COVERS THE CENTRAL ATLC WITH THE AXIS EXTENDING FROM 28N54W THROUGH AN UPPER LOW NEAR 20N60W CONTINUING INTO THE E CARIBBEAN ACROSS THE LEEWARD/WINDWARD ISLANDS TO THE ABC ISLANDS. THE UPPER LOW IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 19N-21N BETWEEN 61W-64W. A BROAD E/W UPPER RIDGE COVERS THE REMAINDER OF ATLC S OF 30N E OF 55W ANCHORED NEAR 22N37W. A BROAD SURFACE RIDGE DOMINATES THE ATLC N OF 25N E OF 60W ANCHORED N OF THE DISCUSSION AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW