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| #900180 (Received by flhurricane at: 10:44 PM 27.Aug.2017) TCDAT5 Potential Tropical Cyclone Ten Discussion Number 2 NWS National Hurricane Center Miami FL AL102017 1100 PM EDT Sun Aug 27 2017 Deep convection has been increasing in both intensity and coverage during the past several hours in association with Potential Tropical Cyclone Ten. However, satellite and radar data indicate that the circulation remains poorly defined, therefore, the system is not yet a tropical cyclone. The initial intensity is held at 30 kt based on the surrounding surface observations and the earlier ASCAT data. The disturbance is located in weak steering currents, and has been meandering during the last several hours. A continued slow and erratic motion is likely to continue overnight and early Monday. A mid- to upper-level trough currently over the central U.S. is expected to approach the system, and should cause the disturbance to begin moving northeastward by late Monday. A faster east- northeastward to northeastward motion is forecast thereafter when the system becomes embedded in the mid-latitude westerlies. The models are in fair agreement, and only small changes were made to the previous NHC track forecast. This forecast takes the center of the disturbance near the Georgia and South Carolina coasts tonight and Monday and along the North Carolina coastline Monday night and Tuesday. The elongated center of the disturbance is located to the west of the main area of deep convection due to strong westerly vertical wind shear. The shear is only expected to lessen a little during the next 12 to 24 hours, but it will likely weaken enough to allow the system to become a tropical cyclone. After that time, increasing shear and interaction with the aforementioned trough should cause the disturbance to lose its tropical characteristics in about 48 hours. Strengthening is likely for a couple of days while the system is post-tropical due to baroclinic effects. Although the potential for tropical storm winds are within the warning time period (36 hours), given the uncertainty in whether these winds will occur on land in northeastern South Carolina and southeastern North Carolina, a tropical storm watch remains in effect for those areas. Note that north of Duck, North Carolina, hazards from this system will be handled with non-tropical products issued by local National Weather Service offices. FORECAST POSITIONS AND MAX WINDS INIT 28/0300Z 30.5N 80.8W 30 KT 35 MPH...POTENTIAL TROP CYCLONE 12H 28/1200Z 30.9N 81.0W 35 KT 40 MPH...TROPICAL CYCLONE 24H 29/0000Z 32.3N 79.9W 35 KT 40 MPH 36H 29/1200Z 34.4N 77.5W 35 KT 40 MPH...NEAR THE COAST 48H 30/0000Z 36.5N 73.8W 45 KT 50 MPH...POST-TROPICAL 72H 31/0000Z 39.9N 64.2W 55 KT 65 MPH...POST-TROP/EXTRATROP 96H 01/0000Z 43.2N 53.4W 60 KT 70 MPH...POST-TROP/EXTRATROP 120H 02/0000Z 47.2N 41.1W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Cangialosi |
