A warning of impending sustained surface winds of hurricane force (64 knots/ 73 mph or greater) within 24 hours or less. A hurricane warning can remain in effect when dangerously high water or a combination of dangerously high water and exceptionally high waves continue even though the winds may be less than hurricane force. For maritime interests, the storm-warning signals are 1) two square red flags with black centers by day and 2) a white lantern between two red lanterns by night. See storm warning.