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Tropical Storm Kristy Discussion Number  15
NWS National Hurricane Center Miami FL       EP132018
800 AM PDT Fri Aug 10 2018

Kristy appears to have at least maintained its strength over the
past several hours. A partial hit from the AMSR instrument at 0950
UTC indicated a closed or nearly-closed mid-level eye was present,
and this feature was still apparent in SSMI imagery a few hours
later. Convection near Kristy's center has also recovered after a
brief decrease earlier this morning. There is a large spread in the
latest satellite intensity estimates. Objective estimates from the
UW-CIMSS ADT and SATCON are around 50 kt, while the latest
subjective Dvorak classification from SAB supports an intensity of
77 kt. The initial intensity has been held at 60 kt as a compromise
between the various estimates, but this estimate is perhaps more
uncertain than usual.

In the short term, Kristy still has a brief period to maintain its
intensity for about 12 hours while the shear is low and it remains
over marginally warm SSTs around 26C. In fact, I can't rule out that
Kristy could briefly become a hurricane later today. Beginning
tomorrow, the cyclone will be moving over cooler waters, and steady
weakening should begin. The intensity guidance is in very good
agreement on this solution for 24 hours and beyond. By early next
week, the tropical storm will likely lose all convection and become
a remnant low, while continuing to gradually spin down over sub-24C
waters.

The initial motion is now 010/8 kt. Kristy should continue moving
generally northward for the next couple of days, towards a weakness
in the subtropical ridge created by John and to the east of a large
upper-level trough located over the central Pacific. Once the
cyclone becomes a remnant low, it should turn gradually westward,
steered by the low-level flow. Even the GFS no longer shows any
significant interaction between Kristy and the remnants of John, so
the NHC forecast has shifted substantially southwestward by the end
of the forecast period, close to the HCCA and TVCN consensus aids.
Additional adjustments in this direction may be required if it
becomes clear that Kristy will weaken sooner than currently
forecast.

FORECAST POSITIONS AND MAX WINDS

INIT  10/1500Z 18.9N 129.8W   60 KT  70 MPH
 12H  11/0000Z 19.9N 129.6W   60 KT  70 MPH
 24H  11/1200Z 20.9N 129.5W   50 KT  60 MPH
 36H  12/0000Z 21.6N 129.7W   40 KT  45 MPH
 48H  12/1200Z 22.1N 130.1W   35 KT  40 MPH
 72H  13/1200Z 23.3N 131.5W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  14/1200Z 24.0N 133.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  15/1200Z 24.5N 135.0W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Zelinsky

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