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Tropical Storm Jose Discussion Number  60
NWS National Hurricane Center Miami FL       AL122017
500 AM EDT Wed Sep 20 2017

Enhanced BD-curve infrared imagery shows considerable decay of
yesterday afternoon's burst of deep convection near Jose's center.
An earlier GPM low-frequency microwave overpass revealed that the
strongest convection and associated winds were located in the north
and west periphery of of the cyclone's circulation, a wind pattern
indicative of non-tropical systems.  Based on the deteriorating
cloud pattern and a blend of the latest subjective T-numbers from
TAFB and SAB, the initial intensity is lowered to 55 kt.  Jose has
begun its movement north of the Gulf Stream's north wall and over
decreasing oceanic temperatures.  Subsequent CIMSS shear analysis
and the SHIPS model indicate modest southwesterly shear undercutting
the outflow aloft.  These inhibiting factors should result in
additional weakening, and the official forecast calls for Jose to
become a post-tropical cyclone in 48 hours, if not sooner.

The initial motion is estimated to be northeastward, or 040/7 kt.
There is no significant change to the previous track forecast or
philosophy.  The large-scale models continue to agree on Jose
decreasing in forward speed and gradually turning toward the east on
Thursday morning in response to a mid-tropospheric shortwave trough
moving eastward out of the eastern Canadian provinces.  Through
the remainder of the forecast period, high pressure is expected to
build over the northeast U.S. and adjacent waters, causing Jose to
drift southward and southwestward through the 72 hour period.  After
that time, the cyclone is expected to basically meander in the
northwest Atlantic within the weak steering flow produced by the
aforementioned high pressure to the northwest of the cyclone and a
building mid-level ridge to the southeast.  The NHC forecast a
little slower at days 4 and 5 and closely follows the GFS/ECMWF
(GFEX) consensus and the forecast input from NOAA Ocean Prediction
Center.


KEY MESSAGES:

1. While the center of Jose is forecast to remain offshore of the
U.S. east coast, the large cyclone is expected to cause some direct
impacts in portions of New England, and a tropical storm warning
is in effect for Cape Cod, Block Island, Martha's Vineyard, and
Nantucket.

2. Minor to moderate coastal flooding is possible from Delaware to
southern New England during the next several days.  Please see
products issued by local National Weather Service forecast offices.

3. Swells generated by Jose are affecting Bermuda, the Bahamas, and
much of the U.S. east coast.  These swells are likely to cause
dangerous surf and rip current conditions for the next several days
in these areas.

4. Jose is expected to produce additional rainfall accumulations of
1 to 2 inches over Martha's Vineyard and Cape Cod, and 2 to 4 inches
in Nantucket as it passes offshore today into Thursday.  This
rainfall could cause isolated flash flooding.


FORECAST POSITIONS AND MAX WINDS

INIT  20/0900Z 38.4N  70.3W   55 KT  65 MPH
 12H  20/1800Z 39.1N  69.3W   55 KT  65 MPH
 24H  21/0600Z 39.6N  68.1W   50 KT  60 MPH
 36H  21/1800Z 39.5N  67.8W   45 KT  50 MPH
 48H  22/0600Z 39.2N  68.3W   40 KT  45 MPH...POST-TROPICAL
 72H  23/0600Z 38.9N  69.4W   40 KT  45 MPH...POST-TROPICAL
 96H  24/0600Z 39.2N  69.5W   35 KT  40 MPH...POST-TROPICAL
120H  25/0600Z 39.5N  68.9W   30 KT  35 MPH...POST-TROPICAL

$$
Forecaster Roberts

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