wind signal

from The Collaborative International Dictionary of English v.0.48

Wind signal \Wind signal\
   In general, any signal announcing information concerning
   winds, and esp. the expected approach of winds whose
   direction and force are dangerous to shipping, etc. The
   wind-signal system of the United States Weather Bureau
   consists of storm, information, hurricane, hot wind, and
   inland storm signals.
   [Webster 1913 Suppl.]