000 AXNT20 KNHC 160016 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI SEP 15 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 GORDON IS CENTERED NEAR 31.1N 53.5W AT 15/2100 UTC AND IS STATIONARY. ESTIMATED MINIMUM CENTRAL PRESSURE IS 976 MB. MAXIMUM SUSTAINED WINDS ARE 80 KT WITH GUSTS TO 100 KT. GORDON IS NOW A CATEGORY ONE HURRICANE ON THE SAFFIR-SIMPSON HURRICANE SCALE. ADDITIONAL WEAKENING IS FORECAST DURING THE NEXT 24 HOURS. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. INFRARED IMAGERY HAS SHOWN THAT THE CLOUD TOPS NEAR THE CENTER OF GORDON HAVE WARMED A BIT. SCATTERED MODERATE CONVECTION NOW LIES FROM 30N-33N BETWEEN 52W-55W. TROPICAL STORM HELENE WAS CENTERED NEAR 16.7N 42.8W AT 15/2100 UTC MOVING WEST-NORTHWEST AT 13 KT. THIS MOTION IS EXPECTED TO CONTINUE DURING THE NEXT DAY OR TWO. ESTIMATED MINIMUM CENTRAL PRESSURE IS 992 MB. MAXIMUM SUSTAINED WINDS ARE 60 KT WITH GUSTS TO 75 KT. SOME STRENGTHENING IS FORECAST DURING THE NEXT 24 HOURS AND HELENE COULD BECOME A HURRICANE WITHIN 12 HOURS. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. GOES AND METEOSAT SATELLITE IMAGES INDICATE THAT THE CLOUD PATTERN IS BETTER ORGANIZED AND IS MORE TYPICAL OF A STRONG TROPICAL STORM. THE CONVECTION IS MORE CONCENTRATED NEAR THE CENTER...AND THERE IS A WELL-DEFINED CYCLONICALLY CURVED BAND TO THE SOUTH WITH NUMEROUS RAINBANDS ALL AROUND. NUMEROUS STRONG CONVECTION IS NEAR THE CENTER FROM 16N-18N BETWEEN 41W-43W. SCATTERED MODERATE /ISOLATED STRONG CONVECTION IS FROM 13N-19N BETWEEN 37W-45W. ...TROPICAL WAVES... A TROPICAL WAVE IS OFF THE COAST OF AFRICA ALONG 20W S OF 20N MOVING W NEAR 10 KT. THIS WAVE IS ACCOMPANIED BY A 1012MB SURFACE LOW NEAR 15N20W. BROAD CYCLONIC CURVATURE IS CLEARLY NOTED IN THE LOW TO MID CLOUD FIELD...AND IN THE AVAILABLE SURFACE OBSERVATIONS. CLOUD TOPS ASSOCIATED WITH THIS WAVE HAVE WARMED A FEW DEGREES OVER THE LAST FEW HOURS...THOUGH SCATTERED MODERATE TO ISOLATED STRONG CONVECTION STILL EXISTS E OF THE WAVE AXIS FROM 16N-19N BETWEEN 13W-17W. TROPICAL WAVE ALONG 64W HAS BEEN DROPPED. A SURGE OF LOW CLOUDS REMAINS MOVING W NEAR 15 KT. THE SURGE DELINEATES THE LEADING EDGE OF DENSE AFRICAN DUST OVER THE E CARIBBEAN THAT EXTENDS E TO T.S. HELENE. THERE IS NO DEEP CONVECTION E OF 64W IN THE CARIBBEAN. TROPICAL WAVE IS ALONG 74W S OF 17N MOVING W 10 TO 15 KT. THIS WAVE EXHIBITS AN INVERTED V PATTERN ON SATELLITE IMAGERY. PATCHES OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER HISPANIOLA FROM 16N-21N BETWEEN 69W-73W. TROPICAL WAVE IS ALONG 82W/83W S OF 15N MOVING W 10 TO 15 KT. BROAD LOW LEVEL CYCLONIC TURNING IS NOTED OVER THE SW CARIBBEAN SEA AND CENTRAL AMERICA. ISOLATED MODERATE CONVECTION IS FROM 8N-16N BETWEEN 77W-86W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 15N16W 13N25W 14N30W 15N40W 10N47W 8N60W. OUTSIDE OF THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES AND HELENE...CLUSTERS OF WIDELY SCATTERED MODERATE CONVECTION ARE SEEN FROM 11N-14N BETWEEN 28W-33W... AND FROM 13N-17N BETWEEN 33W-37W (JUST E OF HELENE). SCATTERED SHOWERS ARE APPROACHING S AMERICA FROM 7N-10N BETWEEN 50W-60W. ...DISCUSSION... GULF OF MEXICO... A WEAK 1016 MB HIGH IS OVER THE CENTRAL GULF OF MEXICO NEAR 25N87W. WINDS ARE 5-10 KT AROUND THE HIGH. SCATTERED MODERATE CONVECTION IS OVER SOUTH FLORIDA FROM 25N-28N BETWEEN 79W-81W MOSTLY DUE TO A STATIONARY FRONT THAT EXTENDS E TO THE W ATLANTIC. IN THE UPPER LEVELS...BROAD DEEP LAYERED TROUGH COVERS THE E US...THE W ATLC...AND ERN GULF N OF 24N AND E OF 95W MOVING E. A RIDGE IS OVER MEXICO AND THE W CARIBBEAN W OF 95W. EXPECT UPPER LEVEL DIFFLUENCE TO PRODUCE SCATTERED SHOWERS OVER TEXAS...THE GULF OF MEXICO...AND S FLORIDA DURING THE NEXT 24 HOURS. CARIBBEAN SEA... TWO TROPICAL WAVES ARE TRAVERSING THE CARIBBEAN SEA... SEE ABOVE. AN ITCZ ALSO EXTENDS FROM E VENEZUELA TO PANAMA ALONG 9N60W 9N84W. SCATTERED MODERATE TO STRONG CONVECTION IS OVER N VENEZUELA AND N COLOMBIA FROM 8N-12N BETWEEN 71W-77W...AND IS OVER PANAMA AND COSTA RICA FROM 8N-10N BETWEEN 77W-83W. ELSEWHERE...SCATTERED MODERATE CONVECTION REMAINS OVER INLAND CUBA BETWEEN 75W-84W. SIMILAR CONVECTION IS OVER THE YUCATAN PENINSULA FROM 20N-22N BETWEEN 87W-89W. IN THE UPPER LEVELS...NELY FLOW IS OVER THE NW CARIBBEAN W OF JAMAICA... WHILE SWLY FLOW IS OVER THE CENTRAL CARIBBEAN BETWEEN 70W-80W. AN UPPER LEVEL HIGH NE OF THE LEEWARD ISLANDS IS NEAR 22N57W PRODUCING SELY FLOW OVER THE E CARIBBEAN SEA E OF 70W. EXPECT...THE TROPICAL WAVES TO MOVE W WITH CONVECTION DURING THE NEXT 24 HOURS. ATLANTIC OCEAN... A STATIONARY FRONT IS OVER THE W ATLANTIC ALONG 32N73W 26N80W. ISOLATED MODERATE CONVECTION IS WITHIN 60 NM OF THE FRONT. A PREFRONTAL TROUGH IS ALONG 32N66W 25N74W. ISOLATED MODERATE CONVECTION IS WITHIN 60 NM OF THE TROUGH. HURRICANE GORDON IS FURTHER E OVER THE CENTRAL ATLANTIC...SEE ABOVE. A DOMINATE 1025 MB HIGH IS SE OF THE AZORES NEAR 34N22W. IN THE UPPER LEVELS... A TROUGH IS OVER THE W ATLANTIC N OF 25N W OF 75W. AN UPPER LEVEL HIGH IS NE OF THE LEEWARD ISLANDS NEAR 22N57W. GOOD UPPER LEVEL OUTFLOW IS OVER HURRICANE GORDON. A TROUGH IS OVER THE CENTRAL ATLANTIC N OF 20N BETWEEN 30W-40W. A RIDGE IS OVER THE E ATLANTIC N OF 20N AND E OF 30W. T.S. HELENE ALSO HAS GOOD UPPER LEVEL OUT FLOW. $$ FORMOSA