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Tropical Storm Jerry Discussion Number  18
NWS National Hurricane Center Miami FL       AL102019
500 PM AST Sat Sep 21 2019

Jerry has become quite disorganized this afternoon. The low-level
center is exposed to the northwest of a small area of persistent
deep convection. The NOAA G-IV aircraft, which is flying a research
mission in and around the tropical storm, measured a minimum
pressure of 1004 mb with 17 kt of wind, implying that the minimum
pressure of Jerry has increased since this morning. However, ASCAT
data from a couple hours after an Air Force Reserve hurricane hunter
plane completed its mission into Jerry showed that the maximum winds
were still 50-55 kt. The max winds are therefore conservatively held
at 55 kt for this advisory.

Only minor adjustments were made to the NHC intensity forecast, and
users should not focus on the 5 kt difference between a tropical
storm and hurricane, especially at 72 h and beyond. Based on Jerry's
disheveled appearance, significant strengthening does not seem
imminent. That said, the HWRF and HMON forecast that the cyclone
will quickly restrengthen tonight or tomorrow and become a hurricane
again. If the shear decreases during the next 24 hours, that is
possible, however SHIPS diagnostics suggest that will not happen.
The NHC forecast instead follows the statistical guidance, and keeps
Jerry in a more-or-less steady state through day 5. The cyclone is
still forecast to be near hurricane strength when it moves near
Bermuda next week, and there is still a distinct possibility that
Jerry will re-gain hurricane strength at some point during the next
5 days.

All of the models still show Jerry turning northward later today or
on Sunday toward a break in the subtropical ridge, and then turning
northeastward ahead of an approaching mid-latitude trough. This
track will bring Jerry close to Bermuda by late Tuesday or early
Wednesday. The model spread has increased a little since the last
advisory, but confidence in this scenario is still high. The NHC
track forecast has been adjusted only slightly to the west and
remains near the multi-model consensus through day 5.

Key Messages:

1. Jerry is forecast to be near hurricane strength when it moves
near Bermuda late Tuesday or early Wednesday. It is too soon to
determine what impacts the system may have on the island but
interests there should monitor the progress of Jerry.


FORECAST POSITIONS AND MAX WINDS

INIT  21/2100Z 23.0N  65.8W   55 KT  65 MPH
 12H  22/0600Z 24.3N  66.9W   55 KT  65 MPH
 24H  22/1800Z 25.8N  67.6W   60 KT  70 MPH
 36H  23/0600Z 27.0N  67.8W   60 KT  70 MPH
 48H  23/1800Z 28.5N  67.8W   60 KT  70 MPH
 72H  24/1800Z 31.5N  66.5W   60 KT  70 MPH
 96H  25/1800Z 35.5N  61.5W   60 KT  70 MPH
120H  26/1800Z 40.0N  56.0W   60 KT  70 MPH

$$
Forecaster Zelinsky

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