National Weather Service United States Department of Commerce

Heat the Southwest; Fire Weather in the Central U.S.; Kona Low Impacting Hawaii

A rare March heat wave is ongoing with much above-normal temperatures over the Southwest U.S. through this weekend. Periods of critical fire weather will persist from the central Rockies to the central and southern Plains through the weekend as gusty winds and low relative humidity continue. A Kona low will continue to bring several rounds of moderate to heavy rainfall to Hawaii through Sunday. Read More >

Fire Weather Watch/Red Flag Warning Criteria
Specific conditions must be met for a Fire Weather Watch and/or a Red Flag Warning to be issued. These conditions are as follows:
1. KBDI greater that or equal to 600, and
2. Two minute ASOS winds greater than or equal to 17 kts (20 mph), or 20 foot winds greater than or equal to 14 kts (16 mph), and
3. Minimum relative humidity of less than 60% in one or more observations, and
4. Low 10-hr fuel moisture, typical less than 13.
5. Monthly precipitation less than two inches with a decrease and/or cessations of percolation (dew)can signal the onset of the fire season. Forecaster judgment must be used in the watch/warning decision making process.