000 AXNT20 KNHC 231741 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN SEP 23 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... POST-TROPICAL CYCLONE NADINE WAS AGAIN UPGRADED TO TROPICAL STORM NADINE AT 23/1500 UTC. TROPICAL STORM NADINE IS CENTERED NEAR 30.6N 25.6W AT 23/1500 UTC OR ABOUT 450 NM S OF THE AZORES MOVING W AT 2 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 986 MN. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUST TO 60 KT. PLEASE SEE LATEST NHC FORECAST/ ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 28N-34W BETWEEN 22W-28W. ...TROPICAL WAVES... TROPICAL WAVE IS E OF THE LESSER ANTILLES EXTENDING FROM 15N51W TO 10N55W MOVING W 15-20 KT. WAVE IS BETWEEN AN UPPER TROUGH THE W AND AN UPPER RIDGE TO THE E. CONVECTION IS MORE ASSOCIATED WITH THE ITCZ THAN THE WAVE ITSELF. TROPICAL WAVE EXTENDS FROM THE SW GULF OF MEXICO NEAR 21N94W ACROSS S MEXICO INTO THE E PACIFIC NEAR 18N95W MOVING W 10-15 KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE THAT COVERS THE S GULF OF MEXICO AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 20N E OF THE WAVE TO 91W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM A 1012 MB LOW OFF THE COAST OF MAURITANIA NEAR 18N17W ALONG 10N24W TO 7N32W WHERE THE ITCZ CONTINUES ALONG 6N38W TO E OF THE TROPICAL WAVE NEAR 11N53W THEN RESUMES W OF THE WAVE NEAR 11N56W INTO THE SE CARIBBEAN TO 11N67W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 10N-13N BETWEEN 50W-56W...FROM 10N-15N BETWEEN 56W-62W...AND FROM 11N-14N BETWEEN 62W-67W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE ASSOCIATED WITH THE 1012 MB FROM 15N-19N E OF 20W TO INLAND OVER MAURITANIA...WITHIN 200 NM S OF THE MONSOON TROUGH/ITCZ BETWEEN 19W-36W...WITHIN 90 NM N OF THE ITCZ BETWEEN 36W-41W...AND WITHIN 60 NM EITHER SIDE OF THE ITCZ BETWEEN 45W-50W. ...DISCUSSION... GULF OF MEXICO... BROAD DEEP LAYERED TROUGH REMAINS OVER THE E CONUS INTO THE NW ATLC AND N GULF SUPPORTING A COLD FRONT THAT AT 23/1500 UTC EXTENDS ACROSS JACKSONVILLE FLORIDA AND OVER THE FLORIDA PANHANDLE ACROSS MOBILE ALABAMA TO N LOUISIANA. THIS FRONT IS NOT CAUSING ANY SIGNIFICANT WEATHER. HOWEVER...A COUPLE OF SURFACE TROUGHS ARE IMPACTING THE S GULF OF MEXICO. A SURFACE TROUGH EXTENDS FROM GRAND BAHAMA ISLAND ACROSS EXTREME S FLORIDA JUST N OF KEY WEST ALONG 25N82W TO N OF THE YUCATAN PENINSULA NEAR 22N88W GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 90 NM EITHER SIDE OF THE TROUGH AXIS. A SECOND SURFACE TROUGH EXTENDS ALONG THE COAST OF MEXICO FROM LAGUNA MADRE TO 21N96W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 21N-27N W OF 91W TO INLAND OVER MEXICO ENHANCED BY AN UPPER RIDGE THAT EXTENDS ACROSS S MEXICO INTO THE NW CARIBBEAN. THIS IS LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES THIS AFTERNOON. TROPICAL WAVE WILL MOVE ACROSS THE REMAINDER OF THE BAY OF CAMPECHE THROUGH TONIGHT AND INLAND OVER MEXICO MON. WEAK COLD FRONT WILL MOVE ACROSS THE N GULF THIS AFTERNOON THEN BECOME STATIONARY ACROSS THE CENTRAL GULF BY TONIGHT. THE FRONT WILL GRADUALLY WASH OUT THROUGH WED AS HIGH PRESSURE NE OF THE AREA GRADUALLY WEAKENS. CARIBBEAN SEA... AN UPPER RIDGE EXTENDS ACROSS S MEXICO AND THE YUCATAN PENINSULA TO 19N80W ENHANCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 16N W OF 84W TO OVER THE YUCATAN AND THROUGH THE YUCATAN CHANNEL. AN UPPER LOW IS OVER THE E CARIBBEAN NEAR 16N64W EXTENDING AN UPPER TROUGH W TO 17N78W ENHANCING THE ACTIVITY ASSOCIATED WITH THE ITCZ AXIS ACROSS THE SE CARIBBEAN. THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 10N75W ACROSS S NICARAGUA INTO THE E PACIFIC REGION NEAR 12N84W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 75 NM EITHER SIDE OF THE MONSOON TROUGH BETWEEN 75W-80W AND FROM THE MONSOON TROUGH TO 14N W OF 80W TO INLAND OVER CENTRAL AMERICA. THIS IS LEAVING THE REMAINDER OF THE CARIBBEAN UNDER MOSTLY CLEAR SKIES THIS AFTERNOON. FRESH TO STRONG TRADE WINDS WILL CONTINUE IN THE SW CARIBBEAN THROUGH AT MON NIGHT BEFORE DIMINISHING. TROPICAL WAVE E OF THE LESSER ANTILLES WILL ENTER THE E CARIBBEAN MON NIGHT CONTINUING INTO THE CENTRAL CARIBBEAN WED AND THU. ATLANTIC OCEAN... BROAD DEEP LAYERED TROUGH REMAINS OVER THE E CONUS INTO THE NW ATLC AND N GULF SUPPORTING A COLD FRONT THAT AT 23/1500 UTC EXTENDS INTO THE DISCUSSION AREA NEAR 32N79W ACROSS JACKSONVILLE FLORIDA AND OVER THE FLORIDA PANHANDLE. A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM 32N75W TO 28N79W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120 NM SE OF THE TROUGH AXIS. A SURFACE TROUGH OVER THE SE GULF OF MEXICO EXTENDS FROM GRAND BAHAMA ISLAND INTO THE GULF OF MEXICO JUST S OF MIAMI FLORIDA GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM EITHER SIDE OF THE TROUGH AXIS. A NARROW UPPER LOW/TROUGH IS WEDGE BETWEEN A PAIR OF UPPER RIDGES ROUGHLY CENTERED NEAR 31N58W WITH A SURFACE TROUGH EXTENDING THROUGH 32N59W ALONG 30N59W TO 27N60W. THE UPPER TROUGH IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 23N-27N BETWEEN 56W-62W. THE E ATLC IS DOMINATED BY NEWLY REFORMED TROPICAL STORM NADINE...SEE SPECIAL FEATURES ABOVE. A SURFACE TROUGH EXTENDS FROM SW OF NADINE NEAR 25N31W TO 20N45W WITH ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF THE TROUGH AXIS. THIS IS THE LEAVING THE REMAINDER OF THE ATLC WITH FAIR WEATHER THIS AFTERNOON. THE PRE-FRONTAL SURFACE TROUGH WILL LIFT N AND MERGE WITH THE WEAK COLD FRONT TODAY. THE COLD FRONT WILL REACH FROM NEAR 32N76W TO CAPE CANAVERAL TONIGHT AND FROM 32N69W TO MIAMI FLORIDA MON NIGHT WHERE IT WILL BECOME STATIONARY AND GRADUALLY DISSIPATE THROUGH WED AS HIGH PRESSURE BUILDS S IN ITS WAKE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW