[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT41 KNHC 142035
TCDAT1

Tropical Storm Josephine Discussion Number  13
NWS National Hurricane Center Miami FL       AL112020
500 PM AST Fri Aug 14 2020

An Air Force Reserve Hurricane Hunter aircraft reported that the
circulation of Josephine was still closed, and that the center was
a little farther to the north than previously thought - possibly
due to reformation close to a strong convective burst.  The
aircraft reported a minimum pressure of 1004 mb, and the combination
of flight-level and SFMR winds support an initial intensity of
35 kt.  Satellite imagery indicates that Josephine is encountering
increasing westerly shear, with cirrus clouds west of the storm
blowing into the cyclone.

Aside from the nudge to the north, the initial motion is generally
west-northwestward or 300/14 kt.  There is again no change to the
track forecast philosophy.  Josephine should continue a west-
northwestward motion as it approaches a weakness in the subtropical
ridge in 48-60 h.  Then, the cyclone should gradually turn
northward and move through the weakness in 72-96 h.  Late in the
forecast period, Josephine or its remnants are expected to turn
north-northeastward along the southern edge of the mid-latitude
westerlies.  Portions of the forecast track have been adjusted
northward based mainly on the initial position, and the new
forecast track lies close to the various consensus models.

The increasing shear means that Josephine is just about out of time
to intensify.  The intensity forecast calls for a little
strengthening tonight in case a convective burst causes some spin
up.  After that, the cyclone should weaken, with the new forecast
showing it becoming a depression in 48 h and a remnant low by 96
hr. The global models continue to forecast a faster weakening, and
there is still the alternative scenario that Josephine could decay
to a tropical wave before 96 h.

KEY MESSAGES:

1. Josephine should pass far enough to the northeast of the Leeward
Islands over the weekend 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  14/2100Z 17.8N  56.1W   35 KT  40 MPH
 12H  15/0600Z 18.6N  58.0W   40 KT  45 MPH
 24H  15/1800Z 19.9N  60.5W   40 KT  45 MPH
 36H  16/0600Z 21.1N  62.9W   35 KT  40 MPH
 48H  16/1800Z 22.5N  65.1W   30 KT  35 MPH
 60H  17/0600Z 24.1N  66.7W   30 KT  35 MPH
 72H  17/1800Z 25.7N  67.7W   25 KT  30 MPH
 96H  18/1800Z 28.6N  67.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  19/1800Z 32.1N  65.5W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven
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