NWS Central Pacific Hurricane Center Honolulu HI EP082023
500 PM HST Mon Aug 14 2023
Greg's convection continues to pulse, and remains concentrated on
the west side of the center due to southeasterly shear in the
vicinity. Objective Dvorak intensities range from 34 to 42
kt, and subjective intensities from PHFO, SAB and JTWC are between
2.5 and 3.0. Using a blend of these estimates, maintaining the
initial intensity at 40 kt.
The initial motion is 270/10 kt. Greg continues to move to the west
on the southern edge of the subtropical ridge to the north. Expect
little change in this over the next couple of days, with Greg
heading in a west to slightly west-northwest direction. As the
system reaches the western edge of the ridge, it is expected to
weaken and slowly take a turn to the southwest. On this path, Greg
will pass far south of the Hawaiian Islands Thursday and Friday,
with no direct impacts to the state. The forecast track remains
similar to the previous forecast, with some influence from the HCCA
and TVCE. The track slows the forward progress a bit for hours 36 to
60 based on the HCCA and TVCE, and is a touch further north around
hour 60.
Greg remains over very warm waters, with weakening southeasterly
shear. Over the next 36 hours, the shear is expected to weaken,
which will allow Greg to slowly strengthen. The forecast intensity
is on the high end of the consensus models during this time, and
then follows the gradual weakening trend in the guidance. Between
hours 48 and 60, Greg will move over slightly cooler waters, with an
increase in deep layer shear, and mid-level dry air beginning to
feed into the system. These all contribute to the weakening of the
system between days 2 and 3, with Greg becoming post-tropical on day
4, and opening up into a trough and dissipating by day 5.
FORECAST POSITIONS AND MAX WINDS
INIT 15/0300Z 11.3N 143.1W 40 KT 45 MPH
12H 15/1200Z 11.5N 145.0W 45 KT 50 MPH
24H 16/0000Z 11.7N 147.4W 45 KT 50 MPH
36H 16/1200Z 12.1N 149.9W 45 KT 50 MPH
48H 17/0000Z 12.7N 152.2W 40 KT 45 MPH
60H 17/1200Z 12.8N 154.6W 40 KT 45 MPH
72H 18/0000Z 12.6N 157.3W 35 KT 40 MPH
96H 19/0000Z 11.8N 162.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 20/0000Z...DISSIPATED
$$
Forecaster M Ballard