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Tropical Storm KRISTY


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Tropical Storm Kristy Discussion Number   6
NWS National Hurricane Center Miami FL       EP132018
200 AM PDT Wed Aug 08 2018

Satellite images indicate that Kristy is not well organized, with a
dry slot wrapping around the northwestern side of the circulation.
In addition the center is on the northwestern edge of an area of
deep convection; an artifact of continued shear.  A scatterometer
pass revealed maximum winds of about 35 kt, which is a fair bit
below the satellite estimates.  The initial wind speed is held at a
possibly generous 40 kt since convection has increased in the past
few hours.

Shear from an upper-level low to the north-northeast of Kristy is
forecast is relax in a day or so, and by that time the cyclone will
probably have mixed the current dry air intrusion.  Thus some
restrengthening is shown commencing beyond 24 hours.  There is
only a narrow window for intensification, however, since between
48-72 hours the SSTs should become rather marginal with a possible
increase in a shear. The guidance has come down markedly from the
last cycle, with most of the models surprisingly showing no increase
in strength.  This forecast will lower the winds about 10 kt from
the previous one during days 1-4, but is still about 10 kt above the
consensus at those time frames since the environment doesn't appear
to be that hostile.

No change has been made to the initial motion estimate of 285/7 kt.
Kristy should turn northwestward by this evening and then northward
late Thursday as a narrow ridge is eroded away to the north of the
cyclone.  While some binary interaction with Hurricane John is
possible, it seems like Kristy will be steered toward John, then
turn northwestward in about 96 hours due to weak ridging developing
between the cyclones.  Model guidance is coming into better
agreement on this scenario, with the ECMWF and GFS solutions
converging toward the model consensus.  The latest NHC forecast is
slow to a blend of the corrected-consensus guidance, and is very
close to the previous NHC track forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  08/0900Z 14.2N 128.5W   40 KT  45 MPH
 12H  08/1800Z 14.8N 129.4W   40 KT  45 MPH
 24H  09/0600Z 15.5N 130.2W   40 KT  45 MPH
 36H  09/1800Z 16.4N 130.5W   45 KT  50 MPH
 48H  10/0600Z 17.3N 130.5W   50 KT  60 MPH
 72H  11/0600Z 19.5N 130.0W   50 KT  60 MPH
 96H  12/0600Z 21.5N 130.5W   40 KT  45 MPH
120H  13/0600Z 23.0N 132.0W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Blake

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