000 AXNT20 KNHC 232339 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT SEP 23 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN SECTIONS OF SOUTH AMERICA...AND THE 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... HURRICANE HELENE IS CENTERED NEAR 38.0N 44.4W OR ABOUT 945 MILES...1520 KM...WEST OF THE AZORES AT 23/2100 UTC MOVING EAST-NORTHEAST AT 19 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 970 MB. MAXIMUM SUSTAINED WIND SPEED IS 80 KT WITH GUSTS TO 100 KT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/ WTNT23 KNHC FOR MORE DETAILS. SATELLITE IMAGERY SHOWED THAT A SMALL AREA OF DEEP CONVECTION DEVELOPED OVER AND JUST NORTH OF THE CENTER. SCATTERED MODERATE CONVECTION IS FROM 38N-39N BETWEEN 43W-45W. A BAND OF SCATTERED MODERATE CONVECTION IS NW OF THE CENTER FROM 38N-44N BETWEEN 44W-47W. HELENE IS BARELY MAINTAINING TROPICAL CHARACTERISTICS AND IS EXPECTED TO TRANSFORM INTO AN EXTRATROPICAL CYCLONE IN THE NEAR FUTURE. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 43W S OF 16N. A 109 MB LOW IS BEHIND THE WAVE AXIS NEAR 18N41N. BROAD LOW/MID LEVEL CYCLONIC ROTATION COVERS A LARGE AREA WITH CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION FROM 16N-21N BETWEEN 36W-43W. SLOW DEVELOPMENT OF THIS SYSTEM IS POSSIBLE OVER THE NEXT COUPLE OF DAYS AS IT MOVES TOWARD THE NORTHWEST AT ABOUT 10 MPH. MEANWHILE...THE TROPICAL WAVE WILL CONTINUE TO MOVE WWD AT 10-15 KT. TROPICAL WAVE IS ALONG 60W S OF 20N MOVING W 10 KT. THE WAVE SHOWS AN INVERTED-V CLOUD PATTERN ON SATELLITE PICTURES. SCATTRED SHOWERS AND ISOLATED TSTMS ARE AFFECTING THE WINDWARD ISLANDS FROM 12N-17N BETWEEN 57W-62W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N15W 8N25W 14N38W 10N50W 13N60W. OUTSIDE FROM THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-8N BETWEEN 16W-25W. SCATTERED MODERATE CONVECTION IS FROM 11N-13N BETWEEN 30W-32W. ...DISCUSSION... GULF OF MEXICO... THE GULF OF MEXICO HAS SLY RETURN FLOW DUE TO SURFACE RIDGING. ISOLATED MODERATE CONVECTION IS OVER W CUBA FROM 22N-24N BETWEEN 81W-86W. FAIR WEATHER DOMINATES THE REMAINDER OF THE GULF. A COLD FRONT IS OVER CENTRAL TEXAS MOVING SE. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS CENTERED OVER THE SE GULF OF MEXICO NEAR 23N88W WITH STRONG SUBSIDENCE EXCEPT NEAR THE CONVECTION MENTIONED ABOVE. EXPECT THE COLD FRONT TO ENTER THE NW GULF OF MEXICO SUNDAY MORNING WITH CONVECTION. THE REMAINDER OF THE GULF WILL HAVE CONTINUED SE SURFACE FLOW AND FAIR WEATHER. CARIBBEAN SEA... MODERATE TRADEWINDS ARE NOTED OVER THE CARIBBEAN SEA. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS INLAND OVER EL SALVADOR...GUATEMALA...AND S MEXICO FROM 13N-19N BETWEEN 88W-94W. ISOLATED MODERATE CONVECTION IS OVER HISPANIOLA...AND CUBA...BETWEEN 71W-80W. IN THE UPPER LEVELS... CYCLONIC FLOW IS OVER THE NW CARIBBEAN DUE TO THE UPPER LEVEL LOW OVER THE SE GULF OF MEXICO. THE REMAINDER OF THE CARIBBEAN HAS NELY TO ELY UPPER LEVEL FLOW WITH STRONG SUBSIDENCE. EXPECT MORE CONVECTION OVER THE W CARIBBEAN AND CENTRAL AMERICA OVER THE NEXT 24 HOURS... AS WELL AS MORE SHOWERS OVER THE E CARIBBEAN DUE TO THE TROPICAL WAVE. ATLANTIC OCEAN... A 1023 MB HIGH IS OVER THE W ATLANTIC NEAR 35N65W PRODUCING FAIR WEATHER. A SURFACE TROUGH IS S OF HURRICANE HELENE ALONG 32N44W 26N56W. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE TROUGH. A 1019 MB HIGH IS OVER THE E ATLANTIC NEAR 32N30W. IN THE UPPER LEVELS... AN UPPER LEVEL HIGH IS OVER THE W ATLANTIC NEAR 28N73W. A SMALL UPPER LEVEL LOW IS CENTERED N OF THE LEEWARD ISLANDS NEAR 20N63W. ANOTHER UPPER LEVEL LOW IS CENTERED NEAR 20N50W. A LARGE HIGH IS CENTERED OVER THE CAPE VERDE ISLANDS NEAR 18N25W. $$ FORMOSA