[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT41 KNHC 151433
TCDAT1

Tropical Storm Josephine Discussion Number  16
NWS National Hurricane Center Miami FL       AL112020
1100 AM AST Sat Aug 15 2020

Josephine has a sheared cloud pattern in satellite imagery this
morning, with the low-level center located near the western edge of
the main convective area.  An Air Force Reserve Hurricane Hunter
aircraft investigating the storm reported flight-level winds as
high as 47 kt at 925 mb, along with surface wind estimates from the
Stepped Frequency Microwave Radiometer of 35-40 kt.  Based on these
data, the initial intensity remains 40 kt.  The aircraft also
reported that, while the area of westerly winds south of the center
was small, the circulation is still closed and that the central
pressure was near 1008 mb.

The storm has moved a little to the left since the last advisory,
with the motion now west-northwestward or 290/14 kt.  Other than
that, there is little change in the forecast track or the forecast
track philosophy.  During the next 2-3 days, Josephine or its
remnants are likely to continue to move west-northwestward to the
south and southwest of a subtropical high pressure area.  After
that, the system is forecast to re-curve to the north and
north-northeast through a break in the western portion of the high.
The new NHC forecast lies to the the center of the tightly-
clustered guidance and near the various consensus models.

Josephine is expected to remain in an environment of moderate to
strong westerly shear for at least the next 48-60 h.  This should
cause the system to weaken, with the new intensity forecast now
calling for Josephine to weaken to a depression between 36-48 h and
degenerate to a remnant low by 72 h.  Several global models forecast
the cyclone to degenerate to a tropical wave before 72 h, and this
remains a viable alternative forecast scenario, especially
considering how small the closed circulation is.  There is a chance
that Josephine or its remnants could encounter a less hostile
environment after 72 h.  However, it is unclear at this time whether
there will be enough left of the system to take advantage of that.


KEY MESSAGES:

1. Josephine should pass far enough to the northeast of the Leeward
Islands today and tonight to prevent major impacts.  However,
interests there should continue to monitor its progress until the
storm has passed north of that area.

2. Locally heavy rainfall is possible in the northern Leeward
Islands, the Virgin Islands, and Puerto Rico as Josephine passes by
to the northeast. Isolated minor flooding is possible in Puerto
Rico through Monday.


FORECAST POSITIONS AND MAX WINDS

INIT  15/1500Z 19.1N  60.2W   40 KT  45 MPH
 12H  16/0000Z 19.8N  61.9W   40 KT  45 MPH
 24H  16/1200Z 21.0N  64.1W   35 KT  40 MPH
 36H  17/0000Z 22.3N  66.3W   35 KT  40 MPH
 48H  17/1200Z 23.8N  67.9W   30 KT  35 MPH
 60H  18/0000Z 25.2N  68.7W   30 KT  35 MPH
 72H  18/1200Z 26.7N  69.1W   25 KT  30 MPH
 96H  19/1200Z 29.0N  68.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  20/1200Z 32.5N  64.5W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven
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