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| #801188 (Received by flhurricane at: 10:47 PM 05.Sep.2015) TCDAT2 TROPICAL STORM GRACE DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072015 1100 PM AST SAT SEP 05 2015 Most of the deep convection associated with Grace is located west and southwest of the estimated center position, consistent with light-to-moderate easterly shear analyzed over the cyclone by UW-CIMSS and the SHIPS model. The initial intensity remains 35 kt based on the latest Dvorak classifications from TAFB and SAB. Grace will be moving over warm waters and in a low shear environment for the next 24 to 36 hours, which should support some strengthening. After that time, the shear becomes westerly and increases with the cyclone moving over slightly cooler waters. As a result, much of the intensity guidance suggests that Grace will weaken later in the period, with dissipation also possible. The new NHC intensity forecast is similar to the previous one and is close to the latest IVCN intensity consensus. The initial motion estimate is 280/12. Grace should continue moving generally westward to west-northwestward to the south of a subtropical ridge for the next several days. The track model guidance is in good agreement on this scenario, although there is some variability in forward speed. The new NHC track forecast is an update of the previous one and lies a little south of the consensus given that Grace is forecast to be weaker by the end of the period. This track is close to the latest predictions from the GFS model and the FSU Superensemble. FORECAST POSITIONS AND MAX WINDS INIT 06/0300Z 12.8N 27.5W 35 KT 40 MPH 12H 06/1200Z 13.0N 29.5W 40 KT 45 MPH 24H 07/0000Z 13.3N 32.3W 45 KT 50 MPH 36H 07/1200Z 13.6N 35.1W 50 KT 60 MPH 48H 08/0000Z 14.1N 38.0W 45 KT 50 MPH 72H 09/0000Z 14.8N 44.2W 45 KT 50 MPH 96H 10/0000Z 15.3N 49.5W 40 KT 45 MPH 120H 11/0000Z 16.0N 54.5W 35 KT 40 MPH $$ Forecaster Brennan |
