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#873219 (Received by flhurricane at: 10:56 PM 28.Aug.2016) TCDAT3 TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL082016 1100 PM EDT SUN AUG 28 2016 Satellite imagery shows that Tropical Depression Eight is currently comprised of a swirl of low-level clouds accompanied by minimal shower activity. This structure is due to the impacts of 20-25 kt of southeasterly vertical wind shear and abundant mid- to upper-level dry air seen in water vapor imagery. Satellite intensity estimates from TAFB and SAB remain 30 kt, so that is the initial intensity for this advisory. The initial motion is 285/9. For the next 48 hours, the depression is expected to move west-northwestward to northwestward toward a weakness in the subtropical ridge near the North Carolina coast. After that time, a mid-latitude shortwave trough moving through the northeastern United States is forecast to erode the ridge and cause the cyclone to recurve northeastward into the westerlies. The track guidance is in good agreement with this scenario, and the new track forecast lies near the consensus models through 48 hours. The dynamical models forecast the shear to decrease during the next 48 hours and for the depression to move into a more moist environment. Based on this, the intensity guidance is showing strengthening as the system approaches the coast of North Carolina. The intensity forecast also shows some strengthening, but it is on the low side of the guidance envelope due to uncertainty about whether the environment will become as favorable as the models are suggesting. After recurvature, the cyclone is forecast to merge with a cold front and dissipate after 72 hours. The 48 hour position is about 35 n mi from Cape Hatteras. This, combined with the various uncertainties in the forecast, requires a tropical storm watch for portions of the North Carolina coast at this time. FORECAST POSITIONS AND MAX WINDS INIT 29/0300Z 32.2N 72.1W 30 KT 35 MPH 12H 29/1200Z 32.8N 73.4W 30 KT 35 MPH 24H 30/0000Z 33.5N 74.6W 35 KT 40 MPH 36H 30/1200Z 34.1N 75.3W 35 KT 40 MPH 48H 31/0000Z 34.9N 75.1W 40 KT 45 MPH 72H 01/0000Z 37.6N 71.5W 40 KT 45 MPH 96H 02/0000Z...DISSIPATED $$ Forecaster Beven |