Official Discussion issued by the National Hurricane Center

Josephine (AL112020) DATA RELEASED: 8/14/2020 3:00:00 AM UTC

Copy of official data

Tropical Storm Josephine Discussion Number  10
NWS National Hurricane Center Miami FL       AL112020
1100 PM AST Thu Aug 13 2020

Enhanced infrared GOES 16 imagery and a recent ASCAT-A overpass
indicated that the center of circulation is still located to
the south of a rather shapeless deep convective mass.  Recent
images show a small burst developing just to the west of the center,
but the associated cloud tops are already warming.  Based on the
overall cloud pattern, light southerly shear and a dry, relatively
stable surrounding environment continue to hamper significant
development.  There were no changes to the satellite intensity
estimates from TAFB and SAB, and the initial intensity is once
again held at a possibly generous 40 kt.

Josephine's relatively small window of opportunity for further
strengthening is within the next 18 to 24 hours.  The forecast
still shows a peak intensity of 50 kt at the time and is above all
of the skilled guidance.  After which, strong southwesterly shear
produced by a northeast to southwest oriented deep-layer
mid-Atlantic trough is expected to induce gradual weakening.  This
inhibiting upper wind pattern is forecast to affect the cyclone
through day 5.  The NHC forecast through 60 hours is based on the
better performing IVCN consensus which consists of the Decay SHIPS,
LGEM and the hurricane models.  Beyond mid-period, the forecast is
basically a blend of the IVCN and the global models which now shows
Josephine degenerating into a remnant low at day 5.

The initial motion is estimated to be west-northwestward, or 300/15
kt within the southwestern periphery of a subtropical high situated
to the northeast of Josephine.  Weakening of the western portion of
the ridge should cause Josephine to turn northwestward in 3 days,
followed by a turn generally northward at day 4 in response to a
major shortwave trough approaching the east coast of the U.S. and
the western Atlantic.  The official forecast is a little faster than
the previous one through 5 days and is once again close to the HFIP
Corrected Consensus model.

Josephine should pass far enough to the northeast of the Leeward
Islands over the weekend to prevent major impacts.  However,
interests in the area should continue to monitor its progress until
the storm has passed north of that area.


FORECAST POSITIONS AND MAX WINDS

INIT  14/0300Z 14.8N  52.2W   40 KT  45 MPH
12H  14/1200Z 15.8N  54.0W   45 KT  50 MPH
24H  15/0000Z 17.3N  56.7W   50 KT  60 MPH
36H  15/1200Z 18.8N  59.5W   45 KT  50 MPH
48H  16/0000Z 20.0N  62.1W   40 KT  45 MPH
60H  16/1200Z 21.3N  64.4W   40 KT  45 MPH
72H  17/0000Z 22.8N  66.2W   35 KT  40 MPH
96H  18/0000Z 26.0N  67.7W   30 KT  35 MPH
120H  19/0000Z 29.5N  66.9W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Roberts