[8/1/18] Fire Weather Watch for Wednesday/Thursday
Hot and dry weather coupled with breezy winds will create hazardous fire conditions
during the afternoon and evening hours today and tomorrow (Wednesday/Thursday).
The National Weather Service in Spokane has issued a Fire Weather
Watch for wind and low relative humidity, which is in effect from
Thursday afternoon through Thursday evening.
Cooler temperatures arriving Friday will end this situation.
A Red Flag Warning remains in effect for Wednesday afternoon and evening.
* Affected Area: Fire Weather Zone 677 East Washington Central
Cascade Valleys (Okanogan/Methow/Chelan)
* Winds: West 10 to 20 mph with gusts up to 30 mph.
* Relative Humidities: 10 to 20 percent in the valleys and 20 to
30 percent over the higher terrain.
* Impacts: The combination of strong winds and low humidity will
lead to rapid spread of new or existing wildfires.
Definitions of a Fire Weather Watch and a Red Flag Warning
A Fire Weather Watch or Red Flag Warning is issued when the combination of dry fuels and weather
conditions support extreme fire danger. These products are written for land and fire managers to
highlight the increased fire danger.
Each National Weather Service office creates local criteria for fire weather watches and red flag
warnings. Common criteria include:
1. Sustained 20 foot winds of 20 mph or higher.
2. Afternoon relative humidity less than 25%.
3. 10 hour fuel moisture at 8% or less for one day.
A Fire Weather Watch is issued up to 72 hours before the above conditions are expected to occur.
A Red Flag Warning is issued when the conditions above are expected to occur or are occurring within
the next 24 hours.