WTPA41 PHFO 021503

500 AM HST FRI SEP 02 2016
Latest satellite images show that Lester remains a strong and well-
organized hurricane, with a solid ring of cold cloud tops
surrounding the eye. However, the eye has been shrinking, and eye
temperatures have cooled somewhat since the previous advisory,
while the outflow has diminished in the southern semicircle. These
observations indicate that Lester has weakened somewhat overnight.
Subjective Dvorak current intensity estimates from HFO/SAB/GTW
ranged from 5.5/102 kt to 6.0/115 kt, while UW-CIMSS ADT yielded
5.3/97 kt. As Lester appears weaker since reconnaissance aircraft
last determined the intensity was near 100 kt, the current intensity
for this advisory is set to 95 kt. Another reconnaissance flight
into Lester is planned for later this morning, while the G-V will
conduct one more synoptic surveillance mission later today before
heading back to the mainland. 

The initial motion vector for this advisory is 295/12 kt, and
Lester has been tracking to the right of the previous forecast track
overnight. Lester is expected to track toward the west-northwest on
the southern flank of a low-to mid-level ridge over the next couple
of days. A turn toward the northwest and north at the end of the
forecast is expected as Lester nears the southwestern and western
periphery of the ridge. On day 5, Lester will be close to a mid-
latitude trough approaching from the west. While the spread in the
guidance suite increases at that time, the earlier periods of the
forecast feature tightly clustered guidance. The updated forecast is
essentially an update of the previous, and lies very close to the
TVCN multi-model consensus. The updated forecast track has Lester
passing the latitude of the Big Island this morning, allowing the
hurricane watch to be discontinued. 

The updated intensity forecast indicates that Lester has reached
peak intensity, and will steadily weaken through the forecast
period, as depicted by nearly all the intensity guidance. Initially,
some of that weakening may be due to a temporary decrease in water
temperatures, as Lester is currently tracking over the area where
Hurricane Madeline rapidly intensified earlier this week. Overall,
the weakening trend is based on persistent and gradually increasing
vertical wind shear supplied by the southerly flow aloft between an
upper-level trough near Hawaii and an upper-level anticyclone to the
east, although significantly decreasing water temperatures on day 4
and 5 will contribute as well. The official intensity forecast
closely follows the LGEM and SHIPS guidance.
A Hurricane Watch remains in place for portions of the main Hawaiian
Islands as the official forecast still brings the system close to
portions of the chain. Although forecast model guidance has been
stable for the past couple of days, and the official forecast keeps
the center of Lester northeast of the islands, a westward deviation
from the official forecast track could bring profound impacts to
Hawaii. In addition, users are also reminded that impacts from
hurricanes can occur well away from the center.
INIT  02/1500Z 19.7N 148.4W   95 KT 110 MPH
 12H  03/0000Z 20.4N 150.2W   85 KT 100 MPH
 24H  03/1200Z 21.4N 152.8W   80 KT  90 MPH
 36H  04/0000Z 22.6N 155.6W   70 KT  80 MPH
 48H  04/1200Z 23.9N 158.3W   60 KT  70 MPH
 72H  05/1200Z 27.0N 163.0W   60 KT  70 MPH
 96H  06/1200Z 31.5N 166.5W   55 KT  65 MPH
120H  07/1200Z 37.0N 166.5W   50 KT  60 MPH
Forecaster Birchard