000 AXNT20 KNHC 291752 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI OCT 29 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... TROPICAL STORM SHARY IS CENTERED NEAR 30.2N 65.8W AT 29/1800 UTC OR ABOUT 135 NM SSW OF BERMUDA MOVING NNE AT 10 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. SCATTERED MODERATE CONVECTION IS LOCATED 180 NM FROM THE CENTER WITHIN THE SOUTHERN SEMICIRCLE. ELSEWHERE ISOLATED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF A LINE FROM 36N64W TO 24N72W. THIS AREA OF PRECIPITATION IS LOCATED WITHIN A MARGINAL UPPER LEVEL DIFFLUENT ZONE WEST OF AN UPPER LEVEL TROUGH AXIS THAT EXTENDS FROM 31N64W SW INTO THE WESTERN CARIBBEAN SEA NEAR 16N81W. SEE THE LATEST NHC INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT5/ WTNT35 KNHC AND THE FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. A TROPICAL WAVE EXTENDS FROM 05N54W TO 15N56W MOVING WNW AT 15-20 KT. A 1005 MB LOW IS POSITIONED ALONG THE WAVE AXIS NEAR 09N56 AND CONTINUES TO PROVIDE LOW-LEVEL FOCUS FOR NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION FROM 09N-13N BETWEEN 52W-59W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS ELSEWHERE FROM 06N-16N BETWEEN 50W-60W. ENHANCEMENT OF THE STRONGER ONGOING CONVECTION IS DUE TO UPPER LEVEL DIFFLUENCE PROVIDED BY A BROAD UPPER LEVEL ANTICYCLONE CENTERED NEAR 11N51W. ...ITCZ... ITCZ AXIS IS ANALYZED ALONG 07N11W 09N22W 05N33W 09N54W. A SURFACE TROUGH IS EMBEDDED WITHIN THE ITCZ AND EXTENDS FROM 07N23W TO 17N19W. THIS SURFACE TROUGH AXIS WAS DEPICTED ON AN EARLY MORNING ASCAT PASS AROUND 29/1124 UTC. ISOLATED MODERATE CONVECTION IS WITHIN 150 NM EAST AND 90 NM WEST OF THE TROUGH AXIS S OF 14N. THIS CONVECTION IS LIKELY ENHANCED DUE TO AN UPPER LEVEL TROUGH WITH AXIS ALONG 25W. ELSEWHERE...SCATTERED MODERATE CONVECTION IS FROM 06N-12N BETWEEN 13W-20W...AND FROM 03N-07N BETWEEN 24W-29W...AND WITHIN 240 NM NORTH OF THE AXIS BETWEEN 29W-46W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL LONGWAVE TROUGH EXTENDS ALONG THE EASTERN U.S. COAST FROM THE MID-ATLC STATES SOUTHWESTWARD OVER THE NE GULF TO 26N90W. THIS UPPER LEVEL TROUGHING SUPPORTS A COLD FRONT ANALYZED FROM THE W ATLC ACROSS THE CENTRAL FLORIDA PENINSULA AND INTO THE GULF NEAR FORT MYERS THEN SW ALONG 24N90W TO THE EASTERN MEXICO COAST NEAR 20N96W. ISOLATED SHOWERS AND TSTMS ARE WITHIN 60 NM EITHER SIDE OF THE COLD FRONT. EAST OF THE COLD FRONT...MOSTLY FAIR CONDITIONS PREVAIL UNDER LIGHT NE SURFACE WINDS AND A DRY AND SUBSIDENT UPPER LEVEL RIDGE AXIS ACROSS THE SE GULF AND STRAITS OF FLORIDA. WEST OF THE COLD FRONT...STRONG NORTHERLY WINDS ARE FORECAST THROUGH EARLY SATURDAY WITH NW TO N WINDS REACHING GALE FORCE AS THE FRONT BEGINS TO STALL AND DISSIPATE THROUGH LATE SATURDAY. CARIBBEAN SEA... BROAD SCALE UPPER LEVEL TROUGHING IS LOCATED ACROSS MUCH OF THE CARIBBEAN BASIN WITH AXIS EXTENDING FROM AN ELONGATED UPPER LEVEL LOW CENTERED IN THE SW NORTH ATLC NEAR 24N69W THROUGH THE WINDWARD PASSAGE TO 15N81W. WATER VAPOR IMAGERY NOTES THAT THE AIRMASS ASSOCIATED WITH THE UPPER LEVEL LOW IS MOSTLY DRY AND STABLE...HOWEVER...A STREAM OF MID-LEVEL MOISTURE IS NOTED AROUND THE WESTERN AND SOUTHERN PERIPHERY OF THE BASE OF THE TROUGH PROVIDING ISOLATED SHOWERS AND TSTMS OVER THE GULF OF HONDURAS...AND PORTIONS OF INLAND HONDURAS...AS WELL AS THE SW CARIBBEAN S OF 12N. MOIST SW FLOW ALOFT IS LOCATED EAST OF THE UPPER LEVEL TROUGH AXIS AND IS GENERATING ISOLATED SHOWERS N OF 14N BETWEEN 65W-80W. FARTHER EAST...AS THE TROPICAL WAVE AND ASSOCIATED AREA OF LOWER PRESSURE ALONG 56W CONTINUES TRACKING WEST-NORTHWESTWARD OVER THE NEXT FEW DAYS...LOCALLY HEAVY RAINFALL AND STRONG GUSTY WINDS ARE EXPECTED TO IMPACT THE WINDWARD ISLANDS AND NORTHERN PORTIONS OF VENEZUELA THROUGH THE WEEKEND. ATLANTIC OCEAN... TROPICAL STORM SHARY AND THE TROPICAL WAVE IN THE TROPICAL ATLC ARE THE PRIMARY CONCERNS IN THE ATLC BASIN THIS AFTERNOON...SEE SPECIAL FEATURES ABOVE. THE UPPER LEVEL TROUGH THAT EXTENDS ALONG THE EASTERN U.S. INTO THE NE GULF OF MEXICO SUPPORTS A COLD FRONT THAT ENTERS THE REGION NEAR 32N74W TO THE FLORIDA PENINSULA NEAR JUPITER. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 90 NM EAST OF THE FRONT. A BROAD ELONGATED UPPER LEVEL LOW CENTERED NEAR 24N69W COVERS THE REMAINDER OF THE W ATLC AND EXTENDS INFLUENCE THROUGH THE WINDWARD PASSAGE INTO THE WESTERN CARIBBEAN SEA. THIS UPPER LEVEL FEATURE IS PROVIDING DIFFLUENCE ALOFT ENHANCING THE ISOLATED SHOWERS AND TSTMS ASSOCIATED WITH SHARY. FARTHER EAST OVER THE CENTRAL AND EASTERN ATLC...A SURFACE RIDGE CONTINUES TO DOMINATE W OF 60W WITH ONLY A WEAK 1012 MB LOW CENTERED NEAR 25N44W EMBEDDED WITHIN THE RIDGE. THIS LOW IS LOCATED ON THE WESTERN END OF AN UPPER LEVEL TROUGH THAT EXTENDS AN AXIS FROM THE MADEIRA ISLANDS TO 27N30W TO 27N43W. ISOLATED SHOWERS ARE OCCURRING FROM 23N-27N BETWEEN 40W-46W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN