[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 181454
TCDAT5

Tropical Storm Jerry Discussion Number   5
NWS National Hurricane Center Miami FL       AL102019
1100 AM AST Wed Sep 18 2019

Satellite images indicate that Jerry continues to become better
organized, with a large curved band wrapping around the center.
While microwave data does not show an inner core yet, the overall
satellite presentation has improved during the past several hours.
The initial wind speed is set to 45 kt, which closely matches
almost all of the available Dvorak estimates and a just-arrived
ASCAT-C scatterometer pass.

Further intensification of Jerry is expected during the next day or
two as the cyclone moves over very warm waters within light shear.
While this type of environment could support even more
strengthening than forecast, there is some substantial dry air
around the cyclone, which is forecast to limit the intensification
rates for now.  This forecast leans heavier on the regional
hurricane models HWRF, HMON and COAMPS-TC, which all show a weaker
cyclone than the statistical/dynamical LGEM and SHIPS models.
Most of the guidance shows increasing shear in a couple of days, and
the shear could become somewhat strong by next week.  While little
change in strength is indicated beyond Friday, this usually doesn't
happen in reality, and further changes will be necessary as the
environmental factors become more clear.

The initial motion continues to be west-northwestward, or 290/12
kt.  The subtropical ridge to the north should steer Jerry at a
faster forward speed for the next couple of days.  Afterward, a
northwest to north-northwestward turn, influenced by a weakness in
the aforementioned ridge left behind by Humberto, is expected. The
NHC track forecast is basically an update from the previous advisory
and lies on the left side of the guidance suite, nearest the ECMWF
model and the corrected-consensus forecasts.


Key Messages:

1. Jerry is expected to strengthen and be a hurricane when it moves
near the northern Leeward Islands Friday, although it is too soon to
determine the direct impacts to the islands. Interests there should
ensure they have their hurricane plan in place and monitor the
progress of this system.  Watches could be issued for a portion of
this area this afternoon or evening.


FORECAST POSITIONS AND MAX WINDS

INIT  18/1500Z 14.6N  49.2W   45 KT  50 MPH
 12H  19/0000Z 15.3N  51.0W   55 KT  65 MPH
 24H  19/1200Z 16.3N  53.7W   60 KT  70 MPH
 36H  20/0000Z 17.3N  56.5W   65 KT  75 MPH
 48H  20/1200Z 18.4N  59.5W   65 KT  75 MPH
 72H  21/1200Z 20.5N  65.3W   65 KT  75 MPH
 96H  22/1200Z 23.3N  69.1W   65 KT  75 MPH
120H  23/1200Z 26.5N  70.5W   60 KT  70 MPH

$$
Forecaster Blake
This weather bulletin was brought to you by:
www.nashvilleweather.net