WTPA43 PHFO 180240
Post-Tropical Cyclone Greg Discussion Number 17
NWS Central Pacific Hurricane Center Honolulu HI EP082023
500 PM HST Thu Aug 17 2023
A burst of convection that developed in Greg's northern semicircle
this morning was unable to wrap around the cyclone's core,
apparently due to moderate vertical wind shear. A 2058Z ASCAT pass
found a couple 35 kt wind barbs in association with this convection,
while also indicating that a closed low-level circulation center
(LLCC) may no longer exist. Since then, disorganized convection has
once again developed north of the center, while visible satellite
imagery shows a fully exposed and elongated LLCC. Given the
cyclone's inability to sustain deep convection over the increasingly
ill-defined center for a prolonged period of time, Greg is deemed
to be post-tropical with this advisory. Maximum sustained winds in
the northern semicircle are estimated to be near 30 kt.
The initial motion vector is a somewhat uncertain 265/15 kt, as the
elongated LLCC appeared to relocate westward in response to this
morning's convection. The remnant low will move generally toward the
west (or just south of west) within the trade wind flow supplied by
a surface high far to the north as it weakens to a trough on Friday.
The updated track and intensity forecasts are strongly guided by
regional and global dynamical model guidance.
This is the last advisory issued by the Central Pacific Hurricane
Center on this system. Additional information on this system can be
found in High Seas Forecasts issued by the National Weather Service
in Honolulu, under AWIPS header HFOHSFNP, WMO header FZPN40 PHFO,
and online at weather.gov/hfo/HSFNP.
FORECAST POSITIONS AND MAX WINDS
INIT 18/0300Z 12.0N 158.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
12H 18/1200Z 11.9N 160.5W 30 KT 35 MPH...POST-TROP/REMNT LOW