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#803508 (Received by flhurricane at: 10:37 PM 26.Sep.2015) TCDAT5 TROPICAL DEPRESSION IDA DISCUSSION NUMBER 35 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102015 1100 PM AST SAT SEP 26 2015 Deep convection again pulsed near and to the east of the center of Ida this evening, but is now waning as shear of around 20 kt continues over the cyclone. The most recent ASCAT missed Ida, so the initial intensity remains 30 kt based on persistence. The statistical models continue to suggest that Ida will intensify later in the forecast period, while the GFS and ECMWF show the circulation weakening and eventually elongating and dissipating by day 5 as a front impinges on Ida from the north. The NHC forecast continues to follow the solution of the global models given that the cyclone is currently embedded in a dry environment with moderate shear. It would also not be surprising if Ida were to dissipate sooner than forecast. The initial motion has been to the left of and slower than the previous advisory, and is estimated at 285/04. A continued bend of Ida's track toward the left is forecast as the shallow cyclone comes under the influence of an amplifying low-level ridge to the north. Much of the guidance has trended to the left and faster this cycle, and given the change in the initial motion and the trend in the guidance, the new NHC track is faster and about a half degree south of the previous one. The NHC forecast is close to a blend of the GFS and ECMWF through 48 hours and not far from the GFS after that time. FORECAST POSITIONS AND MAX WINDS INIT 27/0300Z 24.3N 47.4W 30 KT 35 MPH 12H 27/1200Z 24.3N 48.0W 30 KT 35 MPH 24H 28/0000Z 23.8N 49.1W 30 KT 35 MPH 36H 28/1200Z 23.2N 50.8W 30 KT 35 MPH 48H 29/0000Z 22.8N 53.2W 30 KT 35 MPH 72H 30/0000Z 23.2N 57.4W 30 KT 35 MPH 96H 01/0000Z 23.5N 60.5W 25 KT 30 MPH 120H 02/0000Z...DISSIPATED $$ Forecaster Brennan |