000 AXNT20 KNHC 280553 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT THU OCT 28 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURES... A NEAR STATIONARY 1010 MB SURFACE LOW IS CENTERED OVER 1000 NM NW OF THE CAPE VERDE ISLANDS NEAR 27N41W WITH A SURFACE TROUGH EXTENDING NNE TO BEYOND 32N37W. SCATTERED SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS AND GALE FORCE WINDS ARE E OF THE LOW/TROUGH TO 35W BETWEEN 25N-30N. ORGANIZATION HAS CHANGED LITTLE OVER THE PAST FEW HOURS. ALTHOUGH UPPER LEVEL WINDS ARE ONLY MARGINALLY CONDUCIVE FOR DEVELOPMENT...ONLY A SMALL INCREASE IN ORGANIZATION WOULD RESULT IN THE FORMATION OF A TROPICAL STORM. THERE IS A MEDIUM CHANCE OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. A BROAD AREA OF CYCLONIC CURVATURE IS ABOUT 500 NM NE OF THE LEEWARD/VIRGIN ISLANDS WITH A SURFACE TROUGH ANALYZED FROM 27N53W TO 20N57W SUPPORTED BY AN UPPER LOW NEAR 23N62W AND GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 150 NM OF LINE FROM 21N48W TO 26N55W AND SCATTERED SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS WITHIN 120 NM OF LINE FROM 24N59W TO 29N55W. SHOWER/THUNDERSTORM ACTIVITY HAS BEEN INCREASING DURING THE PAST FEW HOURS AND ENVIRONMENTAL CONDITIONS ARE BECOMING CONDUCIVE FOR THE DEVELOPMENT OF A TROPICAL OR SUBTROPICAL DEPRESSION DURING THE NEXT COUPLE OF DAYS. THERE IS A HIGH CHANCE OF THIS SYSTEM BECOMING A SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES W NEAR 15 KT. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 13N42W THROUGH A 1008 MB LOW NEAR 6N45W TO 2N45W MOVING W 15-20 KT. WAVE REMAINS EMBEDDED WITHIN A BROAD MID LEVEL CYCLONIC ROTATION CENTERED JUST TO THE E OF THE LOW CENTER. SCATTERED TO NUMEROUS STRONG CONVECTION IS FROM 8N-12N BETWEEN 41W-49W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION COVERS THE REMAINDER OF THE AREA FROM 3N-14N BETWEEN 40W-52W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N16W 7N27W 8N38W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 5N-8N BETWEEN 9W-15W INCLUDING THE COAST OF SW AFRICA. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 150 NM OF LINE FROM 5N17W TO 8N35W. ...DISCUSSION... GULF OF MEXICO... THE LARGE UPPER TROUGH REMAINS OVER THE U.S. BUT HAS SHIFTED NORTHWARD KEEPING THE ASSOCIATED FRONTAL BOUNDARY WELL INLAND. AN UPPER RIDGE HAS SET UP OVER THE GULF WATERS ANCHORED NEAR TALLAHASSEE FLORIDA EXTENDING A RIDGE AXIS W TO NEAR BROWNSVILLE TEXAS. A SURFACE RIDGE ANCHORED IN THE W ATLC EXTENDS ACROSS THE FLORIDA PENINSULA TO OVER THE E GULF TO 90W. A PERSISTENT UPPER RIDGE REMAINS OVER THE SW GULF ANCHORED OVER S MEXICO COVERING THE GULF WATERS S OF 24N W OF 87W. WATER VAPOR IMAGERY CONTINUES TO INDICATE MODERATE/STRONG SUBSIDENCE AND DRY AIR ALOFT DOMINATES THE GULF GIVING THE GULF MOSTLY CLEAR SKIES AGAIN TONIGHT WITH THE EXCEPTION OF SOME ISOLATED LOW LEVEL SHOWERS WITHIN 60 NM OF LINE FROM 27N90W TO THE YUCATAN CHANNEL/W CUBA NEAR 22N85W. CARIBBEAN SEA... THE BROAD UPPER RIDGE THAT HAS DOMINATED THE CARIBBEAN OVER THE PAST SEVERAL DAYS HAS SHIFTED W NOW ANCHORED OVER S MEXICO COVERING ONLY THE FAR W CARIBBEAN W OF 75W PROVIDING DIFFLUENCE ALOFT AND COUPLED WITH ANY LINGERING MOISTURE OVER THE SW CARIBBEAN CONTINUES TO GENERATE CLUSTERS OF SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS S OF A LINE FROM COLOMBIA NEAR 11N73W TO NE NICARAGUA NEAR 14N84W. A LARGE UPPER LOW OVER THE W/CENTRAL ATLC COVERS THE REMAINDER OF THE CARIBBEAN. WATER VAPOR IMAGERY INDICATES MODERATE SUBSIDENCE AND DRY AIR ALOFT IS MAINTAINED ACROSS THE CENTRAL CARIBBEAN FROM THE LESSER ANTILLES TO THE YUCATAN PENINSULA GIVING THE REMAINDER OF THE BASIN FAIR WEATHER AGAIN TONIGHT WITH SOME POSSIBLE ISOLATED LOW LEVEL SHOWERS MOVING ACROSS THE E CARIBBEAN E OF 75W INCLUDING THE LESSER ANTILLES. ATLANTIC OCEAN... THE UPPER RIDGE ANCHORED OVER THE THE FLORIDA PANHANDLE COVERING THE N GULF OF MEXICO EXTENDS OVER THE FAR W ATLC N OF 24N W OF 74W. A SURFACE RIDGE COVERS THE W ATLC EXTENDING W INTO THE E GULF OF MEXICO ANCHORED BY A 1028 MB HIGH ABOUT 500 NM ENE OF BERMUDA LEAVING THE W ATLC W OF 63W UNDER FAIR CONDITIONS AGAIN TONIGHT. THE SHORTWAVE UPPER TROUGH HAS DEVELOPED INTO AN UPPER LOW ROUGHLY CENTERED 23N62W AND COVERING THE CENTRAL/W ATLC AND THE E CARIBBEAN BETWEEN 50W-74W ENHANCING THE ACTIVITY ASSOCIATED WITH THE POSSIBLE SUBTROPICAL SYSTEM IN THE SPECIAL FEATURES...SEE ABOVE. A VERY WEAK UPPER LOW IS IN THE E/CENTRAL ATLC CENTERED ROUGHLY NEAR 27N39W SUPPORTING THE POSSIBLE TROPICAL SYSTEM IN THE SPECIAL FEATURES...SEE ABOVE. A WEAKENING SURFACE RIDGE CONTINUES TO DOMINATE THE FAR E ATLC N OF 25N E OF 30W ANCHORED BY A 1026 MB HIGH OFF THE COAST OF PORTUGAL. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW