je.st
news
Tropical Depression Fifteen Forecast Discussion Number 3
2020-09-01 10:35:31| National Hurricane Center (Atlantic)
Issued at 500 AM EDT Tue Sep 01 2020 024 WTNT45 KNHC 010835 TCDAT5 Tropical Depression Fifteen Discussion Number 3 NWS National Hurricane Center Miami FL AL152020 500 AM EDT Tue Sep 01 2020 Deep convection remains displaced to the east and southeast of the depression's low-level center due to increasing west-northwesterly shear. Maximum winds are still estimated to be 30 kt, with no appreciable structural changes having occurred since last evening's ASCAT pass, which showed 25-30 kt winds. The initial motion is toward the northeast, or 050/11 kt, with the depression becoming embedded in the mid-latitude westerlies north of the subtropical ridge. Forecast guidance agrees that the cyclone will turn east-northeastward and then eastward during the next 2-3 days, moving farther out into the Atlantic, although there is greater-than-normal spread among the track models mainly due to speed differences. In particular, the ECMWF is one of the fastest models, while the GFS and UKMET hang the cyclone back to the west a little longer. Since many of the consensus aids, including HCCA, are closer to the faster model solutions, the NHC track forecast leans toward the quicker side of things. UW-CIMSS analyses indicate that the shear has increased to 20-25 kt, and it's only expected to get stronger from here. Some slight strengthening of the depression can't be ruled out during the next 12-24 hours while the shear vector is aligned with the storm motion, but by this time tomorrow the shear is likely to be as strong as 35-45 kt out of the northwest. Therefore, little change in strength is now indicated in the official forecast for the next day or two. The shear magnitude is expected to peak in about 48 hours, and the depression is forecast to be a remnant low at that point, if it hasn't become one already. The GFS dissipates the low in about 48 hours, but since the other models hang onto it a little bit longer, the NHC forecast shows dissipation by day 5. FORECAST POSITIONS AND MAX WINDS INIT 01/0900Z 34.1N 74.4W 30 KT 35 MPH 12H 01/1800Z 35.0N 72.5W 30 KT 35 MPH 24H 02/0600Z 36.0N 69.7W 30 KT 35 MPH 36H 02/1800Z 36.9N 67.0W 30 KT 35 MPH 48H 03/0600Z 37.5N 63.9W 25 KT 30 MPH...POST-TROP/REMNT LOW 60H 03/1800Z 37.7N 61.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 04/0600Z 37.8N 58.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 05/0600Z 39.2N 53.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 06/0600Z...DISSIPATED $$ Forecaster Berg
Tags: number
discussion
tropical
depression
Category:Transportation and Logistics