000 AXNT20 KNHC 171156 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT MON OCT 17 2011 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 1145 UTC. ...SPECIAL FEATURES... A BROAD AREA OF LOW PRESSURE COVERS THE NW CARIBBEAN...SE GULF OF MEXICO AND THE YUCATAN PENINSULA WITH A 1003 MB SURFACE LOW CENTERED ALONG THE NE COAST OF THE YUCATAN PENINSULA NEAR 22N87W AT 17/0900 UTC. SCATTERED/NUMEROUS STRONG CONVECTION IS FROM 21N-24W BETWEEN 83W-87W INCLUDING A PORTION OF W CUBA. SCATTERED TO HEAVY RAINS COVER THE REMAINDER OF THE AREA S OF LINE FROM TAMPA FLORIDA ALONG 25N88W TO OVER THE SW GULF AND S MEXICO NEAR 20N96W. THIS SYSTEM CONTINUES TO PRODUCE STRONG GUSTY WINDS OVER THE SOUTHEASTERN GULF OF MEXICO. UPPER-LEVEL WINDS ARE EXPECTED TO BE MARGINALLY CONDUCIVE FOR DEVELOPMENT DURING THE NEXT DAY OR SO BEFORE BECOMING UNFAVORABLE AFTER THAT. ALTHOUGH THIS LARGE DISTURBANCE IS INTERACTING WITH THE YUCATAN PENINSULA... SOME GRADUAL DEVELOPMENT IS STILL POSSIBLE AS THE LOW MOVES TOWARD THE N AT 4-9 KT. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. REGARDLESS OF DEVELOPMENT...LOCALLY HEAVY RAINFALL AND GUSTY WINDS ARE EXPECTED OVER THE YUCATAN PENINSULA...WESTERN CUBA...THE FLORIDA KEYS...AND SOUTH FLORIDA DURING THE NEXT COUPLE OF DAYS. AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE THE LOW THIS AFTERNOON. ...TROPICAL WAVES... TROPICAL WAVE IS ANALYZED OFF THE COAST OF W AFRICA FROM 17N20W TO 9N22W MOVING W AT 10-15 KT. WAVE IS WELL DEFINED IN THE UPPER LEVEL SATELLITE WINDS AND IS EMBEDDED WITHIN A SLIGHT MOISTURE SURGE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 8N-14N BETWEEN 20W-25W. TROPICAL WAVE IS ANALYZED IN THE CENTRAL TROPICAL ATLC FROM 15N39W TO 7N43W MOVING W 10-15 KT. WAVE IS WELL DEFINED IN THE UPPER LEVEL SATELLITE WINDS AND IS EMBEDDED WITHIN A BROAD AREA OF MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 7N-14N BETWEEN 36W AND THE WAVE AXIS. TROPICAL WAVE IS ANALYZED OVER THE LESSER ANTILLES FROM 17N62W TO 10N63W MOVING 10-15 KT. WAVE IS WELL DEFINED IN THE UPPER LEVEL SATELLITE WINDS AND THE LOW LEVEL CLOUD PATTERN ON SATELLITE IMAGERY. WAVE IS ALSO EMBEDDED WITHIN A SLIGHT MOISTURE SURGE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY BUT DUE TO STRONG SUBSIDENCE AND DRY STABLE...THERE IS NO ASSOCIATED DEEP CONVECTION. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE W OF THE WAVE S OF 13N TO THE COAST OF VENEZUELA BETWEEN 65W-68W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO THE COAST NEAR 17N16W THEN RESUMES NEAR 11N24W 10N33W TO 8N41W. THE ITCZ IS DISRUPTED BY THE PRESENCE OF THE TROPICAL WAVES. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 10N-16N BETWEEN 25W-36W. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION DOT THE AREA FROM 4N-7N E OF 16W TO THE COAST OF AFRICA AND FROM 4N-7N BETWEEN 24W-28W. ...DISCUSSION... GULF OF MEXICO... AN UPPER TROUGH OVER THE NW ATLC CONTINUES TO SUPPORT A QUASI- STATIONARY FRONT THAT EXTENDS THROUGH THE W ATLC THEN DISSIPATES ACROSS FLORIDA INTO THE GULF NEAR LAKE OKEECHOBEE TO 26N85W FURTHER ENHANCING THE ACTIVITY ASSOCIATED WITH THE SPECIAL FEATURES ABOVE. SURFACE RIDGE IS BEHIND THE FRONT ANCHORED BY A 1018 MB HIGH OVER SW GEORGIA AND A 1019 MB HIGH IN THE W ATLC NEAR 31N73W. AN UPPER RIDGE IS ANCHORED IN THE YUCATAN CHANNEL COVERING THE SE GULF AND PRODUCING A SHEAR AXIS ACROSS THE GULF THAT EXTENDS FROM FLORIDA NEAR APALACHEE BAY TO NEAR TAMPICO MEXICO. NW OF THIS SHEAR AXIS ARE STRONG SUBSIDENCE AND DRY STABLE AIR ALOFT WITH CLEAR SKIES. TO THE SE...MOIST TROPICAL AIR IS BEING ADVECTED OVER THE GULF AND THE FLORIDA PENINSULA ENHANCING THE ACTIVITY ASSOCIATED WITH THE SPECIAL FEATURES ABOVE. THE STATIONARY FRONT WILL GRADUALLY DISSIPATE THROUGH LATE TONIGHT. THE LOW IN SPECIAL FEATURES ABOVE IS FORECAST TO BEGIN TO TRACK NE TONIGHT TO NEAR 28N83W BY LATE TUE NIGHT... POSSIBLY AS A TROPICAL CYCLONE...BEFORE MOVING ACROSS N CENTRAL FLORIDA. A TROUGH WILL TRAIL SW FROM THE LOW IN ADVANCE OF A STRONG COLD FRONT THAT WILL ENTER THE NW WATERS EARLY TUE. THIS FRONT WILL MOVE QUICKLY SE ACROSS THE AREA TO SE OF THE GULF WED EVENING. HIGH PRESSURE WILL RE-BUILD OVER THE GULF IN THE WAKE OF THE FRONT THROUGH FRI. CARIBBEAN SEA... AN UPPER RIDGE IS ANCHORED OVER THE YUCATAN CHANNEL NEAR 22N85W AND COVERS THE MOST OF THE CARIBBEAN WITH A RIDGE AXIS EXTENDING NE TO OVER THE W ATLC. THIS UPPER RIDGE IS PROVIDING A DIFFLUENT ENVIRONMENT TO ENHANCE THE ACTIVITY ASSOCIATED WITH THE SPECIAL FEATURES ABOVE. EASTERLY SURFACE FLOW COMBINED WITH THE EASTERLY FLOW ALOFT OVER THE SW CARIBBEAN IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 11N BETWEEN COLOMBIA AND COSTA RICA WITH SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 11N-13N W OF 73W TO INLAND OVER CENTRAL AMERICA. THE LOW IN THE SPECIAL FEATURES WILL MOVE SLOWLY NORTHWARD THROUGH TUE MORNING. THE TROPICAL WAVE OVER THE E CARIBBEAN WILL MOVE ACROSS THE E CARIBBEAN THROUGH TUE WHILE WEAKENING. A COLD FRONT WILL PUSH INTO THE NW CARIBBEAN WED REACHING FROM CENTRAL CUBA TO E HONDURAS BY LATE THU WHERE IT WILL STALL. ATLANTIC OCEAN... A BROAD UPPER TROUGH COVERS THE NW ATLC N OF THE DISCUSSION AREA AND SUPPORTING A QUASI-STATIONARY FRONT THAT ENTERS THE REGION NEAR 32N62W EXTENDING ALONG 27N74W THEN W ACROSS THE N BAHAMA ISLANDS AND FLORIDA NEAR LAKE OKEECHOBEE DISSIPATING INTO THE GULF OF MEXICO. AN UPPER RIDGE AXIS EXTENDS FROM THE YUCATAN CHANNEL NEAR 22N85W THROUGH THE STRAITS OF FLORIDA AND THE BAHAMAS ALONG 26N70W TO BEYOND 32N55W PROVIDING A DIFFLUENT ENVIRONMENT TO ENHANCE SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS N OF THE UPPER RIDGE AXIS TO 30N. A NARROWING UPPER TROUGH COVERS THE CENTRAL ATLC EXTENDING FROM AN UPPER LOW 32N33W THROUGH A SECOND WEAKENING UPPER LOW NEAR 20N52W NARROWING FURTHER INTO THE W TROPICAL ATLC AND E CARIBBEAN ACROSS THE WINDWARD ISLANDS TO THE COAST OF VENEZUELA NEAR 10N68W. A WEAK SURFACE RIDGE COVERS THE E AND CENTRAL ATLC BETWEEN 23N-30N E OF 60W. THE WEAK STATIONARY FRONT WILL GRADUALLY DISSIPATE THROUGH TUE MORNING AS A SURFACE RIDGE BUILDS ALONG 31N. THIS RIDGE WILL THEN SHIFT NE AND WEAKEN TUE IN RESPONSE TO A COLD FRONT THAT MOVES OFF THE NE FLORIDA COAST EARLY WED. THE LOW IN THE SPECIAL FEATURES WILL TRACK NE AS A POSSIBLE TROPICAL CYCLONE THEN ACROSS NE FLORIDA...AND POSSIBLY OVER THE FAR NW WATERS TUE NIGHT. THE FRONT WILL REACH FROM 31N74W TO CENTRAL CUBA BY EARLY THU THEN WEAKEN AND BECOME STATIONARY FROM NEAR 31N70W TO CENTRAL CUBA FRI. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW