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Tropical Storm Kristy Discussion Number   8
NWS National Hurricane Center Miami FL       EP132018
200 PM PDT Wed Aug 08 2018

Kristy's overall structure hasn't changed much over the past few
hours, but cloud tops associated with the deepest convection have
noticeably warmed. The intensity estimates from all agencies have
also not changed, so the initial intensity has been held at 40 kt.
Unfortunately, the various intensity models have not changed, either
and the spread remains high. While the HWRF continues to show Kristy
quickly strengthening to hurricane intensity, all of the
statistical-dynamical guidance keeps the tropical storm very weak
throughout the forecast period. The NHC forecast therefore continues
to split the difference between these scenarios and shows slow
strengthening for a couple of days while the cyclone remains in
a low-shear environment. By days 4 and 5, Kristy is forecast to be
moving over much cooler SSTs and through a more stable environment,
which should cause it to weaken and become a remnant low.

The track forecast is also still low confidence. Although Kristy is
currently moving west-northwestward with an initial motion of 300/5
kt, the models are in good agreement that Kristy will turn northward
overnight and tomorrow due to a weakness in the subtropical ridge
created by Hurricane John. The uncertainty grows substantially
beyond 24 h. The GFS continues to insist on a steering flow that
will cause Kristy to become wrapped up in the larger circulation of
John, while the UKMET and ECMWF show only a slow northward motion,
followed by a turn back toward the west or northwest once the
cyclone becomes a remnant low. The NHC forecast has been favoring
the western solution, and I don't see an obvious reason to change
that reasoning at this time.  Therefore, little change has been
made to the track forecast, which lies near a consensus of those two
models, a little west of the multi-model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  08/2100Z 14.7N 129.6W   40 KT  45 MPH
 12H  09/0600Z 15.3N 130.0W   40 KT  45 MPH
 24H  09/1800Z 16.2N 130.3W   45 KT  50 MPH
 36H  10/0600Z 17.2N 130.3W   50 KT  60 MPH
 48H  10/1800Z 18.2N 130.0W   50 KT  60 MPH
 72H  11/1800Z 20.2N 130.0W   45 KT  50 MPH
 96H  12/1800Z 21.3N 130.7W   35 KT  40 MPH
120H  13/1800Z 22.0N 132.0W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Zelinsky

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