000 AXNT20 KNHC 012347 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT SEP 01 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 2315 UTC. ...SPECIAL FEATURES... TROPICAL STORM KIRK IS CENTERED NEAR 39.5N 44.3W AT 01/2100 UTC OR ABOUT 580 NM SE OF CAPE RACE NEWFOUNDLAND...AND ABOUT 810 NM WNW OF THE AZORES MOVING NE AT 25 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. SCATTERED MODERATE CONVECTION IS MAINLY E OF THE SYSTEM FROM 38N-41N BETWEEN 42W-45W. SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. TROPICAL STORM LESLIE IS CENTERED NEAR 19.2N 57.3W AT 01/2100 UTC OR ABOUT 480 NM E OF THE LEEWARD ISLANDS MOVING WNW AT 16 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 998 MB. MAXIMUM SUSTAINED WIND SPEED IS 55 KT WITH GUSTS TO 65 KT. NUMEROUS STRONG CONVECTION IS FROM 16N-19N BETWEEN 54W-58W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ELSEWHERE FROM 14N-20N BETWEEN 53W-64W...AND FROM 20N-24N BETWEEN 59W-62W. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS W OF THE CAPE VERDE ISLANDS ALONG 19N25W TO A 1011 MB SURFACE LOW AT 13N27W. THE SURFACE LOW IS MAINLY EMBEDDED WITHIN THE MONSOON TROUGH. A DRY AIRMASS ENCOMPASSES THE WAVE TO THE N AND W ALONG WITH DUST. THIS IS INHIBITING ANY CONVECTION NEAR THE WAVE. THE LOW IS EXPECTED TO REMAIN WEAK AS THE WAVE MOVES SLOWLY WESTWARD. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF MAURITANIA AT 20N16W CONTINUING TO THE SURFACE LOW ATTACHED TO A TROPICAL WAVE AT 13N27W AND ENDING NEAR 6N34W. THE ITCZ BEGINS AT 6N34W AND CONTINUES TO 5N46W. NO DEEP CONVECTION IS CURRENTLY NEAR THE MONSOON TROUGH/ITCZ AXIS. ...DISCUSSION... THE GULF OF MEXICO... SURFACE RIDGING CONTINUES TO DOMINATE THE GULF OF MEXICO EXTENDING FROM THE SE CONUS AND WESTERN ATLC. THIS PATTERN IS PROVIDING MAINLY LIGHT E-SE FLOW ACROSS THE BASIN. THE SURFACE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED OVER SOUTHERN TEXAS WITH AXIS EXTENDING TO THE SE CONUS. MOSTLY DRY AIR ALOFT COVERS THE BASIN EXCEPT FOR THE EXTREME NW CORNER WHERE DEEP LAYER MOISTURE IS PRESENT. THIS MOISTURE IS HELPING SUPPORT SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ACROSS THE WESTERN GULF COAST. IT CONTINUES TOWARDS THE NE AND EVENTUALLY WRAPS INTO THE CIRCULATION OF WHAT REMAINS IN ISAAC. A SMALL AREA OF SHOWERS/THUNDERSTORMS HAS ALSO POPPED UP OVER EXTREME SW FLORIDA. THE REMAINDER OF THE BASIN IS UNDER MOSTLY CLEAR SKIES. EXPECT SURFACE RIDGING TO REMAIN ACROSS THE BASIN FOR THE NEXT SEVERAL DAYS. SHOWERS/THUNDERSTORMS ARE EXPECTED TO SPREAD INTO THE NORTH CENTRAL AND NORTHEAST GULF AS THE AREA OF MOISTURE CURRENTLY IN THE NW GULF GETS DRAGGED EASTWARD AS THE THE CIRCULATION OF ISAAC MOVES EASTWARD. THE CARIBBEAN SEA... MOSTLY FAIR WEATHER COVERS THE CARIBBEAN TONIGHT DUE TO WIDESPREAD DRY AIR ALOFT MOVING OVER THE BASIN FROM MAINLY THE NORTH AND EAST. SCATTERED SHOWERS/THUNDERSTORMS ARE NOTED ACROSS THE SW GULF ACROSS COSTA RICA AND PANAMA AS WELL AS FROM 10N-13N BETWEEN 80W-84W. MOST OF THIS ACTIVITY IS ASSOCIATED WITH DIFFLUENCE AROUND AN INVERTED UPPER LEVEL TROUGH OVER SOUTHERN CENTRAL AMERICA. POSSIBLE ISOLATED SHOWERS ARE ALSO ACROSS THE LESSER ANTILLES ASSOCIATED WITH EXTREME OUTER FEEDER BANDS AROUND T.S. LESLIE. LESLIE IS EXPECTED TO MISS THE CARIBBEAN...BUT THE EASTERN ISLANDS MAY STILL RECEIVE SOME RAINFALL AND GUSTY WINDS. MODERATE TRADEWIND FLOW OF 10-15 KT COVERS THE REMAINDER OF THE BASIN. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. THE ATLANTIC OCEAN... AN ALMOST CUT-OFF UPPER LOW NEAR 28N71W CONTINUES TO SUPPORT A DISSIPATING STATIONARY FRONT THAT ENTERS THE DISCUSSION AREA NEAR 31N63W TO 28N73W. ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE AXIS. THE REMAINDER OF THE WEST ATLC IS EXPERIENCING FAIR WEATHER DUE TO BOTH SURFACE RIDGING AND DRY AIR ALOFT SINKING SOUTH AROUND THE EAST SIDE OF AN UPPER LEVEL RIDGE OVER THE EASTERN CONUS. ACROSS THE CENTRAL ATLC...T.S. LESLIE CONTINUES TO SPIN EAST OF THE LESSER ANTILLES. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. UPPER LEVEL RIDGING EXTENDS FROM WEST OF LESLIE TOWARDS THE NE ALONG 32N48W TO 41N34W. THIS UPPER RIDGE IS SUPPORTING WEAK SURFACE RIDGING AROUND A 1022 MB HIGH NEAR 31N43W. AN UPPER LEVEL LOW IS TO THE E CENTERED NEAR 28N38W SUPPORTING A WEAK SURFACE TROUGH ALONG 30N35W TO 27N35W ALONG WITH ISOLATED SHOWERS FROM 25N-31N BETWEEN 36W-42W. THE REMAINDER OF THE EAST ATLC IS COVERED BY AN UPPER LEVEL RIDGE CENTERED OVER NW AFRICA NEAR 20N17W. THE LAST VISIBLE SATELLITE IMAGES OF THE DAY ALONG WITH GOES-R ENHANCEMENT IMAGERY INDICATE A LARGE ARE OF DUST EXTENDS FROM THE COAST OF AFRICA AROUND THE WAVE IN THE E ATLC TO NEAR 45W. THIS DRY AIR MASS IS HELPING SUPPORT FAIR WEATHER IN THE AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON