KADENA AIR BASE, Okinawa — Typhoon Chan-Hom rumbled toward an expected Thursday evening landfall on the Philippines’ northernmost island of Luzon.

From there, it’s forecast to die out before reaching Okinawa, weather officials said.

At 3 p.m. Thursday, Chan-Hom packed sustained 98 mph winds and 121 mph gusts at its center. It was forecast to churn 86 miles north of Clark Air Base at 11 p.m. Thursday, raking what used to be the Air Force’s largest overseas facility with 75 mph sustained winds and 92 mph gusts.

From there, it’s forecast to rapidly lose strength as it dies down Saturday to a tropical depression, with 23 mph sustained winds and 34 mph gusts at 3 p.m..

According to Lt. Cmdr. Jeremy Callahan of the Joint Typhoon Warning Center in Hawaii, “significant wind-shear values” between Luzon and Okinawa will likely prevent Chan-Hom from reorganizing into a significant storm.

“Even though we have it dissipating within 48 hours, we will continue to monitor it” in case it should redevelop, Callahan said.

Chan-Hom is the second numbered and named storm of the 2009 northwest Pacific’s tropical cyclone season. Chan-Hom is Laotian for tree.