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#980751 (Received by flhurricane at: 4:45 PM 03.Sep.2019) TCDAT3 Tropical Depression Eight Discussion Number 1 NWS National Hurricane Center Miami FL AL082019 500 PM AST Tue Sep 03 2019 Satellite images indicate that the broad area of low pressure over the eastern Atlantic has become better defined during day, with rainbands forming on the eastern side of the circulation. This structure is good enough for a tropical depression, and the initial wind speed is set to 30 kt, which agrees with earlier ASCAT passes that showed 25-30 kt. The initial motion estimate is 310/7 kt. A general northwestward motion is anticipated during the next several days, faster by the weekend, as the system is steered by a strengthening eastern Atlantic ridge. One source of uncertainty in the future track is how much the cyclone is affected by a developing mid-level low around 25N45W in a few days. This feature could briefly induce a north-northwestward motion on Friday, and later west-northwestward on day 5 depending on exactly how close the new tropical cyclone gets to the mid-level low. For now it is best not to bite off on any particular model solution, since the intensity and depth of the cyclone isn`t certain at this range. Thus, the forecast is close to the Atlantic model consensus TVCA, shaded a bit on the fast side assuming the system keeps some vertical depth. Although the depression is forecast to be in a low-shear environment during the next couple of days, marginal water temperatures should keep the strengthening rate modest. The intensity forecast is complicated beyond that point due to the system`s interaction with the mid-level low, drier air in the mid-levels, and increasing waters temperatures. This mixed bag of factors makes the forecast rather murky, with any intensity changes at longer range having low predictability at this point. Therefore, the forecast is leveled off at long range, similar to the NOAA corrected-consensus model HCCA, but this uncertain forecast could require a great deal of revision later tonight or tomorrow. FORECAST POSITIONS AND MAX WINDS INIT 03/2100Z 19.0N 32.3W 30 KT 35 MPH 12H 04/0600Z 19.7N 33.2W 35 KT 40 MPH 24H 04/1800Z 20.4N 34.0W 40 KT 45 MPH 36H 05/0600Z 21.4N 34.9W 45 KT 50 MPH 48H 05/1800Z 22.4N 35.8W 45 KT 50 MPH 72H 06/1800Z 26.2N 38.5W 45 KT 50 MPH 96H 07/1800Z 30.0N 41.5W 45 KT 50 MPH 120H 08/1800Z 34.0N 45.5W 45 KT 50 MPH $$ Forecaster Blake |