Posted: Jul 26, 2013 2:36 PM by Meteorologist Mike Heard
Updated: Jul 26, 2013 2:44 PM
Red Flag Warning in effect from noon to 9pm Saturday for gusty winds and low humidities across Deer Lodge and west Beaverhead national forest.
West winds 15-20 mph with gusts up to 30 mph is likely.
Minimum humidities 5%-15%.
Winds will begin to increase around midday Saturday and peak in the later afternoon or early evening. This will coincide with low relative humidity especially down in the valley floors.
North of Wise River will be most affected by critical fire weather conditions. However, locations south of Wise River will still be very dry.
A Red Flag Warning is intended to alert land managers to expected weather conditions that along with sufficiently dry fuels, will significantly increase fire danger.
NOAA Definition of Red Flag Warning
A term used by fire-weather forecasters to call attention to limited weather conditions of particular importance that may result in extreme burning conditions. It is issued when it is an on-going event or the fire weather forecaster has a high degree of confidence that Red Flag criteria will occur within 24 hours of issuance. Red Flag criteria occurs whenever a geographical area has been in a dry spell for a week or two, or for a shorter period , if before spring green-up or after fall color, and the National Fire Danger Rating System (NFDRS) is high to extreme and the following forecast weather parameters are forecasted to be met:
1) a sustained wind average 15 mph or greater
2) relative humidity less than or equal to 25 percent and
3) a temperature of greater than 75 degrees F.
In some states, dry lightning and unstable air are criteria. A Fire Weather Watch may be issued prior to the Red Flag Warning.