The storm was predicted to bring between 5 and 10 inches of rainfall to northern Luzon island before moving on to the South China Sea by late Friday.
Krosa intensified to Category-2 force as it neared Luzon on Thursday, packing maximum sustained winds of almost 100 mph, according to the U.K.-based Tropical Storm Risk.
It was expected to regain some of the strength lost while passing over Luzon before later striking South China's Hainan Island and possibly central Vietnam during the following week.
Typhoon Krosa Track
Satellite Loop Data: CIMSS