The U.S. Navy in Japan uses the Tropical Cyclone Conditions of Readiness to determine conditions of destructive weather from a tropical cyclone, or typhoon.
The following are descriptions of each TCCOR:
• TCCOR 4 (Typhoon Condition IV): Lowest stage. Indicates that a possible threat of destructive winds will occur in 72 hours.
• TCCOR 3 (Typhoon Condition III): Destructive winds are possible within 48 hours.
• TCCOR 2 (Typhoon Condition II): Destructive winds are anticipated in 24 hours.
• TCCOR 1 (Typhoon Condition I): Destructive winds are anticipated within 12 hours.
Definitions provided by the National Weather Service:
• Tropical Storm Watch: A tropical storm watch is issued when a tropical cyclone, or typhoon, containing winds of 39 to 73 mph or higher poses a possible threat, generally within 48 hours. These winds may be accompanied by storm surge, coastal flooding, and/or river flooding. The watch does not mean that tropical storm conditions will occur, it only means that these conditions are possible.
• Tropical Storm Warning: A tropical storm warning is issued when sustained winds of 39 mph to 73 mph or higher associated with a tropical cyclone, or typhoon, are expected in 36 hours or less. These winds may be accompanied by storm surge, coastal flooding, and/or river flooding.
Source: National Weather Service