National Weather Service United States Department of Commerce

CRITERIA for Watches and Warnings (must meet all 3 or 4)

  • During vegetation stage I or II (cured/transition - spring/fall)
    • 1)Winds sustained or frequently gusting above 25 mph.
    • 2) Relative Humidity less than 30%.
    • 3) Rainfall less than 1/4 of an inch during the previous 3 or more days.
  • During vegetation stage III (green - summer)
    • 1)Winds sustained or frequently gusting above 25 mph.
    • 2) Relative Humidity less than 30%.
    • 3) Rainfall less than 1/4 of an inch during the previous 5 or more days.
    • 4) Fuels; Keetch Byram Drought Index (KBDI) above 300.

FIRE WEATHER WATCH

A Fire Weather Watch is used to advise of the possible development of a red flag event in the near future. Usually fire danger is in the very high to extreme category. A Fire Weather Watch will normally be issued 12 to 24 hours in advance of the expected onset of severe fire weather conditions. The watch will be issued via an RFW product (i.e. RFWOKX). The product will contain a headline and the basis for the watch issuance. Fire Weather Watch information will be included in the affected areas of the daily routine Fire Weather Forecast. A Fire Weather Watch will be canceled via an RFW if subsequent information indicates that the conditions are no longer expected to develop.

RED FLAG WARNING

A Red Flag Warning is issued to indicate the imminent danger of severe fire weather with a relatively high probability of occurrence. Usually the fire danger is in the very high to extreme category. A Red Flag Warning will normally be issued for potential severe fire weather events in less than 12 hours. A Red Flag Warning may or may not be preceded by a Fire Weather Watch. The warning will be issued via an RFW product and contain a headline and basis for the warning issuance. Red Flag Warning information will be included in the affected areas of the daily routine Fire Weather Forecast. A Red Flag Warning will be canceled via an RFW if subsequent information indicates that the conditions are no longer expected to develop.

 


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