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#803407 (Received by flhurricane at: 4:34 PM 23.Sep.2015) TCDAT5 TROPICAL STORM IDA DISCUSSION NUMBER 22 NWS NATIONAL HURRICANE CENTER MIAMI FL AL102015 500 PM AST WED SEP 23 2015 Ida's cloud pattern has not changed significantly during the day. The center of the cyclone is located to the west of a small area of deep convection, and the initial intensity is still estimated at 35 kt. Most of the global models indicate that a gradual relaxation of the shear should begin in a day or two, resulting in a little more favorable environment for Ida to re-strengthen. On this basis, the NHC forecast calls for a small increase in intensity beyond 48 hours. This is consistent with the previous forecast and the intensity consensus model. Ida has been drifting generally eastward embedded within the base of a mid- to upper-level trough. This trough is expected to lift out and keep the cyclone moving very slowly toward the northeast during the next 24 hours or so, while embedded within weak steering currents. After that time, Ida is forecast to turn to the north and north-northwest as a subtropical ridge gradually replaces the trough. The NHC forecast has changed very little from the previous one, and is very close to multi-model consensus. One interesting change is that the ECMWF and GFS models had been forecasting Ida to linger for a week or more over the Atlantic as a strong tropical cyclone. However, the most recent runs of both models now show a much weaker system. FORECAST POSITIONS AND MAX WINDS INIT 23/2100Z 19.9N 46.6W 35 KT 40 MPH 12H 24/0600Z 19.9N 46.0W 35 KT 40 MPH 24H 24/1800Z 20.7N 45.8W 35 KT 40 MPH 36H 25/0600Z 21.5N 46.0W 35 KT 40 MPH 48H 25/1800Z 22.5N 46.7W 35 KT 40 MPH 72H 26/1800Z 24.0N 47.5W 40 KT 45 MPH 96H 27/1800Z 25.0N 48.0W 45 KT 50 MPH 120H 28/1800Z 25.5N 48.5W 50 KT 60 MPH $$ Forecaster Avila |