000
WTPZ43 KNHC 212033
TCDEP3

Tropical Storm Kiko Discussion Number  38
NWS National Hurricane Center Miami FL       EP132019
200 PM PDT Sat Sep 21 2019

A pair of ASCAT passes within the past 2-3 hours revealed maximum
winds of 40-45 kt, so Kiko's intensity has been lowered to 45 kt.
The low-level center appears to be moving out from under the
convective cirrus, and the cloud-top temperatures have been warming
significantly for much of the day.  According to analyses from
UW-CIMMS, about 15 kt of southwesterly shear is affecting the
cyclone, but there is a chance that the shear will decrease a bit
as Kiko loses latitude during the next 36 hours.  On the negative
side, Kiko will remain in a relatively dry and somewhat stable air
mass, and these conditions could limit the amount of deep convection
the cyclone is able to produce.  The new NHC intensity forecast is
very close to the IVCN consensus and the HCCA model, keeping a
relatively steady intensity for the next 3 days.  By days 4 and 5,
an increase in shear and lower oceanic heat content should lead to
weakening, and simulated infrared satellite imagery from the GFS
and ECMWF suggest that Kiko's deep convection may dissipate for
good by that time.  As a result, the official forecast now shows
Kiko becoming a remnant low by day 5.

Kiko is now moving slowly west-southwestward, or 250/4 kt.  An
elongated mid- to upper-level trough extending from California to
near the Hawaiian Islands is digging southward, which is forcing
the subtropical ridge--and Kiko--to lose latitude during the next
36 hours.  After that time, the western portion of the trough is
forecast to cut off east of the Hawaiian Islands, causing Kiko to
turn sharply northwestward on days 2-4.  Once a remnant low, Kiko
is then expected to be steered by lower-level flow, causing it to
turn back to the southwest.  The updated NHC track is a little
farther south during the first 2 days to account for the adjusted
initial position, otherwise it's very close the previous forecast
and the various multi-model consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT  21/2100Z 18.0N 131.6W   45 KT  50 MPH
 12H  22/0600Z 17.4N 132.5W   40 KT  45 MPH
 24H  22/1800Z 16.5N 133.6W   40 KT  45 MPH
 36H  23/0600Z 15.9N 134.8W   40 KT  45 MPH
 48H  23/1800Z 16.1N 135.9W   45 KT  50 MPH
 72H  24/1800Z 18.3N 137.5W   40 KT  45 MPH
 96H  25/1800Z 19.0N 138.8W   30 KT  35 MPH
120H  26/1800Z 17.7N 139.5W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Berg