WTPZ42 KNHC 202034
Post-Tropical Cyclone Guillermo Discussion Number 14
NWS National Hurricane Center Miami FL EP072021
200 PM PDT Tue Jul 20 2021
Guillermo's circulation consists of a tight swirl of low-level
clouds, and the earlier brief convective flare up dissipated
shortly after the release of the previous advisory. Given that
the system has been devoid of organized deep convection for most of
the last 18 hours, the system is now considered a remnant low and
this will be the last NHC advisory. The initial intensity remains
30 kt based on a recent ASCAT pass that showed an area of 25-30 kt
winds north of the center.
The post-tropical cyclone will remain in an dry, stable airmass
while moving over SSTs of 24-25C, which should result in a gradual
spin down of the circulation. Global model fields indicate that the
low will open up into a trough within 48-60 hours, and that is
indicated in the official forecast.
The remnant low is now moving a little south of due west, with an
initial motion estimate of 265/15. The system is expected to move
west-southwestward until dissipation under the influence of the
expansive low-level ridge centered over the north-central Pacific.
The new NHC track forecast is a little south of and faster than the
previous one, trending toward the latest consensus aids.
FORECAST POSITIONS AND MAX WINDS
INIT 20/2100Z 18.7N 126.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
12H 21/0600Z 18.2N 128.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 21/1800Z 17.5N 131.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 22/0600Z 16.8N 134.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 22/1800Z 16.1N 137.0W 20 KT 25 MPH...POST-TROP/REMNT LOW