Official Discussion issued by the National Hurricane Center

Paulette (AL172020) DATA RELEASED: 9/9/2020 3:00:00 PM UTC

Copy of official data

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.


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