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#1059320 (Received by flhurricane at: 4:48 PM 29.Aug.2021) TCDAT5 Tropical Depression Ten Discussion Number 7 NWS National Hurricane Center Miami FL AL102021 500 PM AST Sun Aug 29 2021 The depression`s center has again scooted northwestward away from the associated deep convection due to continuing 20-25 kt of northwesterly shear. Since there has been no appreciable change to the various intensity estimates from this morning, the estimated maximum winds remain 30 kt for this advisory. The source of the shear can be seen in water vapor imagery, with high-level clouds emanating from the eastern Caribbean Sea and blowing directly into the depression. In fact, model guidance is now indicating that the shear may increase as high as 35-40 kt during the next 24 hours while the depression moves beneath the subtropical jet stream, and the NHC intensity forecast therefore now shows no intensity change through 36 hours. By 48 hours, the system should have moved north of the subtropical jet, and lower shear and relatively warm waters should finally allow for some strengthening. During the latter part of the forecast period, the NHC intensity forecast is very close to the HCCA and IVCN consensus aids. Much of this forecast is contingent on the depression actually surviving the next 24-36 hours, however. The depression is moving just west of due north (355/10 kt), but the system is expected to slow down and turn slightly toward the north-northeast within 24 hours, ahead of the tail end of a deep-layer trough which extends over much of the central Atlantic. Beginning in about 48 hours, a piece of the east Atlantic subtropical ridge is forecast to pinch off and block the depression, causing it to turn back to the north and north-northwest through the end of the 5-day forecast period. This developing high looks like it will be a little stronger than previously thought, and most of the models have shifted significantly westward after 48 hours. The new NHC track forecast has been adjusted westward as well, but it is not as far west as the deterministic models and the consensus aids. Therefore, additional adjustment may be required in subsequent advisories. FORECAST POSITIONS AND MAX WINDS INIT 29/2100Z 19.7N 50.4W 30 KT 35 MPH 12H 30/0600Z 20.7N 50.3W 30 KT 35 MPH 24H 30/1800Z 22.1N 49.9W 30 KT 35 MPH 36H 31/0600Z 23.3N 49.4W 30 KT 35 MPH 48H 31/1800Z 24.5N 49.3W 35 KT 40 MPH 60H 01/0600Z 25.8N 49.8W 40 KT 45 MPH 72H 01/1800Z 27.4N 50.6W 40 KT 45 MPH 96H 02/1800Z 30.4N 51.9W 50 KT 60 MPH 120H 03/1800Z 33.7N 52.0W 55 KT 65 MPH $$ Forecaster Berg |