WTPZ43 KNHC 272036

200 PM PDT SAT AUG 27 2016

Lester's cloud pattern has increased some in organization during the last several hours. The cyclone's small central dense overcast has become more symmetric, with a well-defined 20 n mi wide eye evident in visible satellite imagery. A broken band is also wrapping around the southeastern semicircle of the Lester's circulation. Dvorak T-numbers are a consensus T5.0 from both satellite agencies. Based on these data, the initial intensity estimate is increased to 90 kt.

Lester has been moving a little faster, and the initial motion estimate is 270/11. A strong subtropical ridge to the north of Lester should steer the cyclone on a nearly due-west course for at least the next few days. After about 72 hours, there are differences in the strength of the subtropical ridge north of Lester, which are somewhat dependent on the progression of a mid-latitude trough through the eastern Pacific. There also exists some potential for binary interaction with Madeline late in the forecast period, which could impart a more poleward motion to Lester. The GFS-based guidance continues to lie on the northern side of the guidance envelope, while the latest ECMWF solution remains on the southern edge. The new track forecast is nearly identical to the previous one through 48 hours but has been shifted northward in the direction of a consensus of the ECMWF, HWRF, GFS, and UKMET models after that time.

A nearly uniform easterly flow over Lester throughout the troposphere is forecast for several days, resulting in a low-shear environment. SSTs should be warm enough next day or so for some intensification, but the environment around Lester will be drying. In about 36 to 48 hours, the hurricane should begin to traverse a region of lower SSTs between 130W and 140W. This will occur at a time when global models forecast the near-storm environment to become extremely dry. Slow weakening should commence around this time and throughout the remainder of the forecast period. This scenario is in line with the guidance, and the new intensity forecast is in best agreement with the multi-model consensus and LGEM.


INIT 27/2100Z 17.9N 119.6W 90 KT 105 MPH 12H 28/0600Z 18.0N 121.3W 95 KT 110 MPH 24H 28/1800Z 18.2N 123.9W 95 KT 110 MPH 36H 29/0600Z 18.3N 126.8W 90 KT 105 MPH 48H 29/1800Z 18.5N 129.6W 85 KT 100 MPH 72H 30/1800Z 18.8N 135.0W 80 KT 90 MPH 96H 31/1800Z 18.9N 139.8W 75 KT 85 MPH 120H 01/1800Z 19.5N 144.6W 70 KT 80 MPH

$$ Forecaster Kimberlain