000 AXNT20 KNHC 061755 CCA TWDAT TROPICAL WEATHER DISCUSSION...UPDATED NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON SEP 06 2010 ***** UPDATED TO CORRECT TIME ***** 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...SPECIAL FEATURES... TROPICAL STORM HERMINE IS CENTERED NEAR 24.1N 96.5W AT 06/1800 UTC OR ABOUT 85 MI ENE OF LA PESCA MEXICO AND ABOUT 140 MI SSE OF BROWNSVILLE TEXAS...MOVING N AT 7 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 995 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUST TO 60 KT. PLEASE SEE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT5/WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. SCATTERED/NUMEROUS STRONG CONVECTION COVERS THE WESTERN HALF OF THE GULF W OF 90W. ALTHOUGH THIS SYSTEM WILL BE INLAND OVER NORTHEASTERN MEXICO OR EXTREME SOUTHERN TEXAS BY LATE THIS EVENING...COMPUTER MODELS SUGGEST THE CONVECTION ASSOCIATED TO THIS SYSTEM WILL LINGER OVER THE NW GULF THROUGH AT LEAST THURSDAY. A 1008 MB LOW...REMNANT OF GASTON...IS ABOUT 300 NM E OF THE NORTHERN LESSER ANTILLES NEAR 17N57W MOVING W NEAR 10 KT. SATELLITE IMAGERY INDICATES A LOW LEVEL SWIRL REMAINS WITH A BAND OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM OF LINE FROM JUST W OF THE LOW NEAR 17N59W TO 22N62W. UPPER LEVEL WINDS ARE EXPECTED TO BECOME MORE CONDUCIVE FOR DEVELOPMENT OVER THE NEXT DAY OR SO AND THE MOISTURE SURROUNDING THE LOW SHOULD GRADUALLY INCREASE AS IT MOVES W AT 10-15 KT. THERE IS A HIGH CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE AGAIN DURING THE NEXT 48 HOURS. HEAVY RAINS AND GUSTY WINDS COULD BEGIN TO AFFECT PORTIONS OF THE LEEWARD ISLANDS LATE TODAY AND TONIGHT. INTERESTS IN THOSE ISLANDS SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. ...TROPICAL WAVES... A TROPICAL WAVE JUST ENTERED THE FAR EASTERN ATLANTIC TROPICAL BASIN...ANALYZED ALONG 15W S OF 16N MOVING WEST 10-15 KT. SATELLITE DERIVED WINDS INDICATE BROAD CYCLONIC TURNING AROUND THE WAVE AXIS. THIS WAVE IS EMBEDDED IN A SURGE OF DEEP LEVEL MOISTURE AS NOTED ON TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE TO STRONG CONVECTION IS BETWEEN THE COAST OF WEST AFRICA AND 23W FROM 8N TO 18N. ...ITCZ... A MONSOONAL TROUGH EXTENDS FROM THE COASTAL WATERS OF W AFRICA NEAR 8N17W CONTINUING WESTWARD ALONG 5N30W TO 8N40W...WHERE THE ITCZ AXIS BEGINS AND CONTINUES WESTWARD ALONG 9N50W TO 8N60W. SCATTERED MODERATE TO STRONG CONVECTION IS BETWEEN THE COAST OF WEST AFRICA AND 23W FROM 8N TO 18N. THIS AREA OF CONVECTION IS ALSO ASSOCIATED WITH A TROPICAL WAVE ALONG 15W S OF 16N. SIMILAR CONVECTION IS WITHIN 100 NM ON EITHER SIDE OF THE MONSOONAL TROUGH. SCATTERED WEAK TO ISOLATED MODERATE CONVECTION IS WITHIN 100 NM EITHER SIDE OF THE ITCZ. ...DISCUSSION... GULF OF MEXICO... THE PRIMARY FOCUS THIS AFTERNOON FOR THE GULF OF MEXICO IS TROPICAL STORM HERMINE PRODUCING CONVECTION TO MOST OF THE WESTERN HALF OF THE GULF W OF 90W. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. A LONGWAVE UPPER LEVEL TROUGH IS EMBEDDED IN THE RIDGE ENTERING THE NE GULF NOTED BY STRONG SUBSIDENCE ALOFT ON WATER VAPOR IMAGERY...WHILE ANTI-CYCLONIC ROTATION ALOFT IS OVER THE SE BASIN INDICATED BY SATELLITE DERIVED WINDS. THIS UPPER LEVEL SCENARIO IS GENERATING DIFFLUENT FLOW ALOFT OVER THE EASTERN GULF E OF 85W SUPPORTING SCATTERED. THIS SCENARIO IS ENHANCING SCATTERED MODERATE TO ISOLATED HEAVY SHOWERS IN THIS REGION. COMPUTER MODELS SUGGEST THAT THE UPPER LEVEL SCENARIO WILL CONTINUE TO GENERATE CONVECTION IN THE EASTERN GULF S OF 27N E OF 85W OVER THE NEXT 24 HRS...INCLUDING THE FLORIDA STRAITS. CARIBBEAN SEA... BROAD ELONGATED UPPER LEVEL LOW CENTERED OVER THE SOUTHERNMOST DISTRICT OF THE BAHAMAS...GREAT INAGUA ISLAND... SUPPORTS A RATHER WEAK SURFACE TROUGH THAT ENTERS THE DISCUSSION AREA THROUGH HAITI ALONG 18N73W TO 17N73W WITH NO ASSOCIATED CONVECTION AT THE MOMENT. HOWEVER...COMPUTER MODELS INDICATE THE UPPER LEVEL LOW WILL CONTINUE TO MOVE WEST AND THE CYCLONIC FLOW AROUND IT WILL INTERACT WITH AN LONGWAVE UPPER LEVEL TROUGH OVER THE EASTERN SEA BOARD TO PRODUCE DIFFLUENCE ALOFT...ENHANCING CONVECTION OVER THE NNW BASIN N OF 18N W OF 77W OVER THE NEXT 24 TO 48 HOURS. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE OVER THE SW BASIN S OF 15N W OF 75W...ASSOCIATED WITH NEARBY CONVERGENCE IN THE VICINITY OF THE MONSOONAL TROUGH OVER THE FAR EASTERN PACIFIC. COMPUTER MODELS SUGGEST THIS AREA OF CONVECTION WILL LINGER IN THIS REGION OVER THE NEXT 24 HRS. RELATIVELY DRY/STABLE CONDITIONS IS NOTED ELSEWHERE ACROSS THE CARIBBEAN THIS AFTERNOON. ON A SIDE NOTE...THE REMNANT LOW PRESSURE CENTER OF GASTON WILL ENTER THE FAR EASTERN CARIBBEAN WITH CONVECTION OVER THE NEXT 24 HOURS AFFECTING THE LESSER ANTILLES FROM 15N TO PUERTO RICO. ATLANTIC OCEAN... THE 1008 MB REMNANT LOW OF GASTON REMAINS A CONCERN AS IT CONTINUES TO MOVE TOWARD THE LEEWARD ISLANDS...SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. BROAD ELONGATED UPPER LEVEL LOW CENTERED OVER THE SOUTHERNMOST DISTRICT OF THE BAHAMAS...GREAT INAGUA ISLAND...SUPPORTS A RATHER WEAK SURFACE TROUGH ANALYZED ALONG 25N71W 21N73W 17N73W ENHANCING SCATTERED WEAK TO MODERATE CONVECTION WITHIN 70 NM ON EITHER SIDE OF THE TROUGH N OF 20N. A LONGWAVE UPPER LEVEL TROUGH IS MOVING OFF THE EASTERN SEABOARD AND IT'S INTERACTING WITH THE CYCLONIC FLOW ALOFT RELATED TO THE ELONGATED UPPER LEVEL LOW TO PRODUCE SCATTERED MODERATE TO ISOLATED STRONG CONVECTION TO THE FAR WESTERN ATLC W OF 76W INCLUDING THE FLORIDA PENINSULA. THIS AREA OF CONVECTION IS EXPECTED TO LINGER IN THIS REGION OVER THE NEXT 24 HRS. A SURFACE TROUGH IS OVER THE EASTERN ATLC EXTENDING FROM 22N27W TO 15N30W GENERATING SCATTERED MODERATE TO ISOLATED STRONG CONVECTION WITHIN 70 NM ON EITHER SIDE OF THE AXIS. THIS SYSTEM WILL CONTINUE TO MOVE WEST WITH CONVECTION OVER THE NEXT 24 HOURS. ELSEWHERE ACROSS THE DISCUSSION AREA...BROAD MID/UPPER LEVEL SUB-TROPICAL RIDGE DOMINATES THE ATLC AND SUPPORTS THE SURFACE 1027 MB HIGH NEAR 38N40W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA