je.st
news
Tropical Storm Paulette Forecast Discussion Number 11
2020-09-09 16:59:55| National Hurricane Center (Atlantic)
Issued at 1100 AM AST Wed Sep 09 2020 000 WTNT42 KNHC 091459 TCDAT2 Tropical Storm Paulette Discussion Number 11 NWS National Hurricane Center Miami FL AL172020 1100 AM AST Wed Sep 09 2020 Morning visible satellite images show that Paulette's center is located beneath a thin veil of cirrus and displaced to the south of the deep convection. Based on a blend of Dvorak estimates from TAFB and SAB, and a recent ASCAT pass which showed an area of 45-50 kt winds northwest of the center, the initial intensity remains 50 kt. A large upper-level trough is located to the northwest of Paulette, and this feature is producing 20-30 kt of south-southwesterly shear over the cyclone. The shear is forecast to increase well over 30 kt during the next day or two as Paulette gets closer to the upper-level disturbance, which should cause the cyclone's maximum winds to gradually decrease through day 3. The shear is forecast to abate somewhat and back around from the southeast by days 4 and 5, which could allow Paulette to restrengthen a little bit over the subtropical Atlantic at that time. The new NHC intensity forecast is identical to the previous one and is generally close to the IVCN intensity consensus and the HCCA corrected consensus. Although Paulette has been hopscotching around a bit, likely being influenced by the sheared convection, the 12-hour motion is now toward the west-northwest (290/8 kt). Subtropical ridging to the north of Paulette is forecast to keep the cyclone on a westward or west-northwestward trajectory for the next 48 hours. After that time, the ridge is likely to weaken a bit, which should allow Paulette to move toward the northwest with some increase in forward speed on days 3 though 5. There is a typical amount of spread among the track models for this forecast, and while they all agree on the general future trajectory, there are some speed differences. In particular, the UKMET and HWRF start out much slower than the other models, and the ECWMF is much faster than the rest of the guidance by days 4 and 5. Relying on continuity and the model consensus aids, the updated NHC track forecast has been shifted very little from the previous prediction. The initial and forecast tropical-storm-force wind radii have been expanded based on the recent scatterometer data. FORECAST POSITIONS AND MAX WINDS INIT 09/1500Z 20.0N 46.5W 50 KT 60 MPH 12H 10/0000Z 20.3N 48.0W 50 KT 60 MPH 24H 10/1200Z 20.7N 49.9W 45 KT 50 MPH 36H 11/0000Z 20.9N 51.6W 45 KT 50 MPH 48H 11/1200Z 21.3N 53.1W 40 KT 45 MPH 60H 12/0000Z 22.2N 54.3W 40 KT 45 MPH 72H 12/1200Z 23.5N 55.6W 40 KT 45 MPH 96H 13/1200Z 27.0N 59.0W 45 KT 50 MPH 120H 14/1200Z 30.0N 62.5W 50 KT 60 MPH $$ Forecaster Berg
Tags: number
discussion
storm
tropical
Category:Transportation and Logistics