Tropical Storm Lane Discussion Number 6
Wiki-Hurricanes Forecast Center
2:00 PM PDT Thu Aug 16 2018
Lane is nearly a hurricane. Satellite animations this afternoon show that the storm is well organized, with convection near -70C across its central dense overcast and numerous spiral bands, especially to the west. Upper-level outflow is beginning to expand in all directions, an indication that the moderate wind shear that has plagued it over the past two days is beginning to relent. Meanwhile, visible images show that a banded eye may be trying to form, and this matches an earlier 15z microwave pass that showed a ragged inner core. Satellite intensity estimates were T3.8/61kt from UW-CIMSS ADT and T4.0/65kt from SAB and TAFB, which would support a hurricane designation. However, considering Lane is still in the process of solidifying its structural integrity, and given that ASCAT has documented a bit of a lag in maximum winds compared to satellite presentation the past few times, the initial intensity has been raised to 60kt.
Broad subtropical ridging north of Lane is keeping the storm on a steady westward track across the East Pacific. This motion will continue for the next 12 hours or so, with a gradual turn toward the west-northwest as a weakness in the mid to upper-levels south of the ridge creates a poleward tug on Lane. By day 5, this weakness will become less apparent and high pressure will re intensify, forcing the storm back westward. At this point, Lane still appears likely to pass south of the Hawaiian Islands, but this is still far from guaranteed.
Now that upper-level winds are beginning to relent, the environment will favor more significant development over the coming days, with ocean temperatures above 28C and mid-level relative humidity value above 65 percent. Once the storm's inner core is solidified, rapid intensification continues to appear likely, with the DTOPS showing a 91% chance of 25kt/24hr RI and a 61% chance of 55kt/48hr RI. The only limiting factors will be intermittent intrusions of environmental dry air as is typical given Lane's current structure, as well as eyewall replacement cycle that cannot be forecast well in advance. By day 5, the storm should encounter moderate to strong wind shear and begin to weaken as a result.
MAXIMUM WINDS FORECAST
INIT 16/2100Z 60 KT 70 MPH
12H 17/0600Z 70 KT 80 MPH
24H 17/1800Z 85 KT 100 MPH
36H 18/0600Z 100 KT 115 MPH
48H 18/1800Z 110 KT 125 MPH...ENTERING CENTRAL PACIFIC
72H 19/1800Z 120 KT 140 MPH
96H 20/1800Z 115 KT 130 MPH
120H 21/1800Z 100 KT 115 MPH