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Tropical Depression Three Forecast Discussion Number 6
2018-07-08 04:34:54| National Hurricane Center (Atlantic)
Issued at 1100 PM EDT Sat Jul 07 2018 000 WTNT43 KNHC 080234 TCDAT3 Tropical Depression Three Discussion Number 6 NWS National Hurricane Center Miami FL AL032018 1100 PM EDT Sat Jul 07 2018 The depression is gradually becoming better organized. Geostationary satellite and microwave images indicate that the center is located on the northern side of a convective burst and to the east of a broken curved band. The initial intensity is held at 30 kt, in agreement with the Dvorak classification from SAB and ADT values from CIMSS at the University of Wisconsin. This estimate also uses data from NOAA buoy 41002 located about 60 n mi south-southeast of the center. An Air Force reconnaissance aircraft is scheduled to investigate the system overnight, and it should provide a better estimate of the cyclone's intensity. Satellite fixes suggest that the depression has now stalled, as forecast. The cyclone is caught in very weak steering currents between two mid-level ridges and a mid- to upper-level trough to its north. A very slow southeastward motion is expected during the next couple of days as ridging builds to the north of the system. Thereafter, a sharp northeastward turn with an abrupt increase in forward speed is predicted when a deep-layer trough approaches the cyclone. The NHC track forecast is adjusted a little to the south of the previous one in the short term based on the latest guidance. The depression is presently over the warm waters of the Gulf Stream Current and it will remain over these warm SSTs during the next few days. In addition, light to moderate wind shear and perhaps some baroclinic forcing from the approaching trough should allow the cyclone to steadily strengthen during the next few days. The NHC intensity forecast is slightly higher than the previous one, and near the middle of the guidance envelope. Extratropical transition is forecast to occur in a little more than 4 days when the system is expected to cross the north wall of the Gulf Stream current and move over very cold waters. Although the depression is expected to remain offshore of the North Carolina coastline, the tight pressure gradient between the depression and high pressure over the northeastern U.S. is expected to produce gale-force winds over Pamlico and Albemarle Sounds. See products issued by the National Weather Service forecast offices for more details. FORECAST POSITIONS AND MAX WINDS INIT 08/0300Z 32.9N 75.1W 30 KT 35 MPH 12H 08/1200Z 32.8N 74.9W 40 KT 45 MPH 24H 09/0000Z 32.6N 74.6W 45 KT 50 MPH 36H 09/1200Z 32.4N 74.3W 50 KT 60 MPH 48H 10/0000Z 32.3N 73.9W 55 KT 65 MPH 72H 11/0000Z 34.5N 71.0W 70 KT 80 MPH 96H 12/0000Z 41.0N 63.0W 70 KT 80 MPH 120H 13/0000Z 49.0N 53.0W 55 KT 65 MPH...POST-TROP/EXTRATROP $$ Forecaster Cangialosi
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