000 AXNT20 KNHC 082345 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT SEP 08 2012 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2245 UTC. ...SPECIAL FEATURES... HURRICANE MICHAEL IS CENTERED NEAR 33.1N 42.3W AT 08/2100 UTC OR ABOUT 800 NM WSW OF THE AZORES MOVING NNW AT 03 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 971 MB. MAXIMUM SUSTAINED WIND SPEED IS 90 KT WITH GUSTS TO 110 KT. NUMEROUS MODERATE CONVECTION IS FROM 32N-34N BETWEEN 42W-43W...WITH SCATTERED MODERATE CONVECTION ELSEWHERE FROM 31N-35N BETWEEN 40W-44W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. TROPICAL STORM LESLIE IS CENTERED NEAR 29.7N 62.6W AT 09/0000 UTC OR ABOUT 190 NM SE OF BERMUDA MOVING N AT 07 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 988 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. NUMEROUS STRONG CONVECTION IS FROM 28N-29N BETWEEN 63W-65W...WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION ELSEWHERE FROM 25N-32N BETWEEN 62W-66W. SCATTERED MODERATE CONVECTION IS ALSO FROM 26N-29N BETWEEN 60W-62W. SEE LATEST NHC INTERMEDIATE PUBLIC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT2/WTNT32 AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/ WTNT22 KNHC FOR MORE DETAILS. TROPICAL WAVE EXTENDS FROM 21N22W TO A 1009 MB SURFACE LOW AT 14N23W. THE WAVE/LOW ARE WITHIN A LARGE AREA OF DEEP MOISTURE WITH MAXIMUM VALUES NEAR THE LOW CENTER EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. MID/LOW-LEVEL CYCLONIC FLOW IS EVIDENT IN SATELLITE IMAGERY AND SATELLITE DERIVED WINDS. SCATTERED MODERATE/STRONG CONVECTION IS MAINLY WEST OF THE AXIS FROM 14N-17N BETWEEN 24W-27W. ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR GRADUAL DEVELOPMENT AS THE LOW/WAVE MOVE WESTWARD AT ABOUT 15-20 KT. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO MAURITANIA WHERE IT HAS BROKEN DUE TO THE CIRCULATION AROUND THE TROPICAL WAVE/LOW DISCUSSED IN THE SPECIAL FEATURES SECTION. THE MONSOON TROUGH CONTINUES FROM THE LOW CENTER AT 14N23W ALONG 13N34W TO 10N45W. IT TRANSITIONS INTO THE ITCZ AT 10N45W TO 8N60W. A SURFACE TROUGH IS WEST OF THE TROPICAL WAVE AND N OF THE MONSOON TROUGH ALONG 21N36W. THIS TROUGH ALSO HAS A GOOD MOISTURE SIGNAL ASSOCIATED WITH IT. CLUSTERS OF STRONG CONVECTION ARE FROM 17N-18N BETWEEN 34W-37W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ELSEWHERE SOUTH OF THE MONSOON TROUGH FROM 8N-10N BETWEEN 22W-30W...AND FROM 7N-9N BETWEEN 34W-40W. ...DISCUSSION... GULF OF MEXICO... MAINLY DRY AIR ALOFT AROUND A WEAK UPPER LEVEL RIDGE COVERS THE GULF OF MEXICO TONIGHT HELPING MAINTAIN FAIR CONDITIONS ACROSS A GOOD PORTION OF THE BASIN. HOWEVER...A WEAK 1009 MB SURFACE LOW IS CENTERED IN THE NE GULF NEAR 30N87W WITH A SURFACE TROUGH EXTENDING TOWARDS THE SW TO 26N92W SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS WITHIN 70 NM SE OF THE TROUGH AXIS. AN UPPER LEVEL TROUGH COVERING THE EASTERN CONUS N OF THE BASIN IS ALSO SUPPORTING A COLD FRONT...WHICH HAS JUST BEGUN TO EMERGE OVER GULF WATERS FROM 31N88W TO 28N98W. RADAR IMAGERY INDICATES A THIN LINE OF SHOWERS/THUNDERSTORMS IS ALONG THE FRONTAL BOUNDARY. THE REMAINDER OF THE BASIN HAS MOSTLY CLEAR SKIES AND FAIR CONDITIONS. THE SURFACE LOW IS EXPECTED TO DISSIPATE WITH THE SURFACE TROUGH REMAINING BEFORE IT ALSO GETS ABSORBED AS THE COLD FRONT SINKS FARTHER SOUTH AND MOVES THROUGH THE BASIN OVER THE NEXT COUPLE OF DAYS. CARIBBEAN SEA... MUCH OF THE CARIBBEAN IS UNDER FAIR CONDITIONS DUE TO DRY AIR ALOFT COVERING THE BASIN AROUND AN ELONGATED UPPER LEVEL TROUGH IN THE NW CARIBBEAN...AND AN UPPER LEVEL RIDGE OVER THE EASTERN CARIBBEAN. HOWEVER...STRONG SHOWERS/THUNDERSTORMS ARE OCCURRING OVER THE MAJORITY OF CENTRAL AMERICA. THE ACTIVITY ACROSS THE NORTHERN PORTIONS OF CENTRAL AMERICA ARE INFLUENCED BY A SURFACE TROUGH ALONG 15N86W TO 10N81W IN COMBINATION WITH UPPER LEVEL DIFFLUENCE AROUND THE UPPER TROUGH INT HE FAR NW CORNER OF THE CARIBBEAN. WIND SPEED CONVERGENCE IS ALSO OCCURRING NEAR THE COAST BETWEEN 20 KT WINDS OBSERVED IN THE CENTRAL CARIBBEAN AND LIGHTER WINDS ALONG THE COAST. THE ACTIVITY FARTHER SOUTH IS LIKELY INFLUENCED BY THE MONSOON TROUGH THAT EXTENDS THROUGH COSTA RICA AND PANAMA TO A 1008 MB LOW OVER NORTHERN COLOMBIA. TRADEWIND FLOW OF 15-20 KT IS ACROSS THE MAJORITY OF THE BASIN WITH LIGHTER WINDS IN BOTH THE FAR EASTERN AND FAR WESTERN CARIBBEAN. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... A NARROW LEVEL TROUGH COVERS THE FAR W ATLC CONTINUING INTO THE NW CARIBBEAN. HOWEVER...DRY AIR ALOFT AROUND THE TROUGH IS INHIBITING ANY SHOWER ACTIVITY AT THIS TIME. A LONGWAVE UPPER TROUGH OVER THE EASTERN CONUS SUPPORTS A COLD FRONT...WHICH IS CURRENTLY ENTERING THE GULF OF MEXICO AND MAY BEGIN TO BRING SHOWERS INTO THE W ATLC. THE MAJORITY OF THE W ATLC IS EXPERIENCING FAIR WEATHER DUE TO BOTH DRY AIR ALOFT AND WEAK SURFACE RIDGING AROUND A 1016 MB HIGH NEAR 24N74W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE...OUTFLOW FROM LESLIE...COVERING THE CENTRAL ATLC. TROPICAL STORM LESLIE IS PRODUCING A LARGE AREA OF WIND, SEAS, AND CONVECTION ACROSS THE CENTRAL ATLC. MUCH SMALLER...BUT STRONGER...HURRICANE MICHAEL SPINS ENE OF LESLIE. SEE SPECIAL FEATURES SECTION FOR MORE DETAILS ON BOTH SYSTEMS. THE REMAINDER OF THE EASTERN ATLC IS DOMINATED BY SURFACE RIDGING EXTENDING FROM A PAIR OF 1022 AND 1023 MB SURFACE HIGHS CENTERED NEAR 33N15W AND 33N29W RESPECTIVELY...WHICH IS PROVIDING FAIR CONDITIONS ACROSS THE REMAINDER OF THE E ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON