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#900486 (Received by flhurricane at: 5:11 AM 29.Aug.2017) TCDAT5 Potential Tropical Cyclone Ten Discussion Number 7 NWS National Hurricane Center Miami FL AL102017 500 AM EDT Tue Aug 29 2017 The disturbance has developed a center that has been trackable this evening though it is still not well-defined, since it appears to be considerably elongated northeast-southwest. The disturbance continues to display very cold, but extremely asymmetric deep convection with all of the thunderstorm activity east of the center due to strong vertical shear. Moreover, the convection is showing no identifiable banding features. So the system is not yet a tropical cyclone. Regardless of the label we use to describe this hybrid system, maximum winds are around 35 kt based upon a Dvorak classification from TAFB and observed winds just below that from the NDBC Buoy 41013. The initial motion of the disturbance is northeast at a faster rate of about 10 kt. Continued acceleration is expected during the next couple of days as a mid- to upper-level trough over the Great Lakes moves closer to the system. The NHC forecast track takes the disturbance across the North Carolina coastline today. By tonight, the cyclone is forecast to move offshore and accelerate over the Atlantic in the mid-latitude westerlies. The NHC track forecast lies near the middle of the guidance envelope and is not substantially changed from the previous advisory. Given the poor organization of the disturbance and the strong wind shear environment that it is embedded within, the chances of this disturbance becoming a tropical cyclone have decreased to about a coin flip. Nonetheless, the potential impacts of tropical-storm- force winds across portions of North Carolina are likely today even if the system does not become a tropical cyclone. The system is expected to become extratropical in 24 hours or less when it interacts with the aforementioned mid- to upper-level trough. Significant strengthening as an extratropical cyclone is forecast for a couple of days due to baroclinic forcing. No significant change has been made to the NHC intensity forecast. The track, intensity, and wind radii forecasts from 24 to 120 h are based on guidance provided by NOAA`s Ocean Prediction Center. FORECAST POSITIONS AND MAX WINDS INIT 29/0900Z 33.5N 78.5W 35 KT 40 MPH...POTENTIAL TROP CYCLONE 12H 29/1800Z 35.4N 76.0W 40 KT 45 MPH 24H 30/0600Z 38.0N 71.5W 50 KT 60 MPH...POST-TROP/EXTRATROP 36H 30/1800Z 39.5N 66.5W 60 KT 70 MPH...POST-TROP/EXTRATROP 48H 31/0600Z 41.0N 61.0W 70 KT 80 MPH...POST-TROP/EXTRATROP 72H 01/0600Z 44.5N 50.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 02/0600Z 50.0N 33.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 120H 03/0600Z 55.0N 19.0W 30 KT 35 MPH...POST-TROP/EXTRATROP $$ Forecaster Landsea |