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#979539 (Received by flhurricane at: 4:51 PM 26.Aug.2019) TCDAT1 Tropical Depression Six Discussion Number 1 NWS National Hurricane Center Miami FL AL062019 500 PM EDT Mon Aug 26 2019 The circulation associated with the area of low pressure that has been tracked across the western Atlantic the past several days has become better defined during the past 24 hours. The associated convection, which is located well to the southeast of the low-level center due to shear, has also become more persistent and organized into a band today. As a result, advisories are being initiated on a tropical depression. The initial wind speed has been set at 30 kt, based on earlier ASCAT data. There were a few 35-kt vectors in the ASCAT-A overpass but those data appeared to be rain-inflated. The depression is currently located over warm water but within an environment of moderate westerly shear, which is likely to continue during the next day or so. Although some slight strengthening is forecast, the shear is likely to prohibit significant deepening during that time. After 36 h, the shear is forecast to decrease while the system moves northeastward and some modest strengthening is anticipated. Later in the period, an approaching mid-latitude trough may also help to strengthen the cyclone due to baroclinic processes, and the system is forecast to become extratropical in 3 to 4 days, and should be absorbed by a larger extratropical cyclone by day 5. The initial motion estimate is a somewhat uncertain 080/2 kt. The depression is forecast to drift eastward or northeastward during the next day or so as it remains in an area of weak steering flow between a couple of mid-level anticyclones. As the aforementioned mid-latitude trough approaches the northeastern United States on Wednesday, it should cause the cyclone to accelerate northeastward well east of the east coast of the United States. The track guidance is in relatively good agreement, but there are some differences in how fast it will be ejected northeastward. The NHC track forecast leans toward the slower ECMWF solution during the first day or so, then closer to the consensus aids later in the period. FORECAST POSITIONS AND MAX WINDS INIT 26/2100Z 31.7N 72.5W 30 KT 35 MPH 12H 27/0600Z 31.8N 72.0W 35 KT 40 MPH 24H 27/1800Z 32.1N 71.9W 35 KT 40 MPH 36H 28/0600Z 32.9N 71.9W 35 KT 40 MPH 48H 28/1800Z 34.6N 71.5W 40 KT 45 MPH 72H 29/1800Z 40.3N 66.8W 45 KT 50 MPH 96H 30/1800Z 47.0N 60.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 120H 31/1800Z...DISSIPATED $$ Forecaster Brown |