000 AXNT20 KNHC 151144 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT SEP 15 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...SPECIAL FEATURES... HURRICANE NADINE IS CENTERED NEAR 30.7N 51.4W 15/0900 UTC OR ABOUT ABOUT 690 NM E OF BERMUDA...AND ABOUT 1280 NM WSW OF THE AZORES. NADINE IS MOVING NE AT 13 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 985 MB. MAXIMUM SUSTAINED WIND SPEED IS 65 KT WITH GUSTS TO 80 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. NUMEROUS STRONG CONVECTION IS FROM 30N-32N BETWEEN 49W-52W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ELSEWHERE FROM 27N-34N BETWEEN 46W-53W. ...TROPICAL WAVES... TROPICAL WAVE MOVES MOVES CLOSER TO THE LESSER ANTILLES WITH AXIS ALONG 15N52W TO 9N49W MOVING W NEAR 15 KT. THE WAVE LIES WITHIN AN AREA OF MAXIMUM MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. AN EARLIER ASCAT SCATTEROMETER PASS ALSO INDICATED THAT LOW-LEVEL CYCLONIC FLOW IS PRESENT AROUND THE WAVE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-16N BETWEEN 46W-56W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF SENEGAL AT 14N17W CONTINUING OVER ATLC WATERS ALONG 10N23W 8N34W. THE ITCZ EXTENDS FROM 8N34W TO 9N42W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 8N-11N BETWEEN 23W-26W...AND FROM 7N-10N BETWEEN 29W-31W. ...DISCUSSION... GULF OF MEXICO... A FEW SHOWERS/THUNDERSTORMS ARE ACROSS THE GULF OF MEXICO THIS MORNING. RADAR IMAGERY CONTINUES TO SHOW SHOWERS/THUNDERSTORMS ALONG THE TEXAS COAST ASSOCIATED WITH A STATIONARY FRONT THAT PARALLELS THE COASTLINE. SOME ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO OVER THE EASTERN GULF AND THE FLORIDA STRAITS ASSOCIATED WITH A SURFACE TROUGH ALONG 28N85W TO 24N84W. SOME OF THIS ACTIVITY IS ALSO SUPPORTED BY DIFFLUENCE ALOFT AROUND AN UPPER LEVEL TROUGH EXTENDING FROM THE FLORIDA PANHANDLE TO THE SW GULF. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO PRESENT IN THE CENTRAL GULF FROM 25N-26N BETWEEN 89W-92W ASSOCIATED WITH A SECOND SURFACE TROUGH ALONG 26N91W TO 22N89W. SCATTERED SHOWERS/THUNDERSTORMS ALSO CONTINUE ALONG THE MEXICO COAST IN THE SW GULF. THIS ACTIVITY IS LIKELY TIED TO THE UPPER TROUGH AS WELL. MOIST CONDITIONS ARE EXPECTED TO REMAIN ACROSS THE BASIN FOR AT LEAST THE NEXT 24 HOURS AS THE UPPER TROUGH REMAINS OVER THE BASIN. CARIBBEAN SEA... THE CARIBBEAN REMAINS MOSTLY CALM THIS MORNING WITH CLEAR SKIES COVERING THE MAJORITY OF THE AREA. THIS FAIR WEATHER IS RELATED TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE COVERING THE ENTIRE CENTRAL AND WESTERN CARIBBEAN. A FEW SHOWERS/THUNDERSTORMS HAVE POPPED UP OVER CENTRAL AMERICA INCLUDING NICARAGUA...COSTA RICA...AND PANAMA. MOST OF THIS ACTIVITY IS TIED TO THE MONSOON TROUGH AXIS EXTENDING FROM THE E PACIFIC THROUGH PANAMA TO NORTHERN COLOMBIA. A VERY NARROW UPPER TROUGH IS OVER THE EASTERN CARIBBEAN EXTENDING FROM PUERTO RICO TO VENEZUELA...BUT IT IS EMBEDDED WITH DRY AIR PREVENTING IT FROM CAUSING ANY ACTIVE WEATHER AT THIS TIME. TRADEWIND FLOW OF 10-15 KT IS PRESENT ACROSS THE AREA WITH SOME STRONGER WINDS NORTH OF COLOMBIA. EXPECT SHOWERS/THUNDERSTORMS ACROSS THE SW CARIBBEAN AND CENTRAL AMERICA DURING THE DAYTIME HOURS WITH LITTLE CHANGE ELSEWHERE OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE COVERS THE MAJORITY OF THE SW NORTH ATLANTIC THIS MORNING PROVIDING MOSTLY FAIR CONDITIONS BESIDES A FEW SHOWERS/THUNDERSTORMS THAT HAVE FORMED ALONG THE EAST COAST OF FLORIDA AND ACROSS THE FLORIDA STRAITS. A NARROW UPPER LEVEL TROUGH EXTENDS FROM 34N63W TO PUERTO RICO SUPPORTING A WEAK SURFACE TROUGH...REMNANTS OF AN OLD FRONTAL BOUNDARY...ALONG 31N68W 27N69W 24N72W. POSSIBLE ISOLATED SHOWERS ARE WITHIN 150 NM E OF THE AXIS. TO THE E...HURRICANE NADINE DOMINATES THE CENTRAL ATLC. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. A WEAK SURFACE HIGH IS E OF NADINE CENTERED NEAR 27N42W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED SOUTH OF NADINE NEAR 23N50W. THE UPPER RIDGE ALONG WITH THE SURFACE RIDGE ARE PROVIDING FAIR CONDITIONS ACROSS THE REMAINDER OF THE CENTRAL AND EASTERN ATLC. AN UPPER LEVEL TROUGH COVERS THE EASTERN ATLC EXTENDING FROM THE AZORES ISLANDS TO NEAR 29N21W 16N38W...BUT IS NOT CAUSING ANY ACTIVE WEATHER IN THE DISCUSSION AREA. THE FIRST VISIBLE SATELLITE IMAGES OF THE DAY ALONG WITH GOES-R ENHANCED IMAGERY INDICATE THAT AN AREA OF SAHARAN DUST EXTENDS S OF 20N FROM THE COAST OF AFRICA TO NEAR 45W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON