Dangerous Cold Weather for Most of the Country; Rare Winter Storm for the South; Fire Weather Concerns for Southern California

Arctic air will filter south and east through early this week. As this cold air moves across the South, a rare winter storm is forecast to develop from Texas, Gulf Coast States into the Southeast through early this week. Several new daily record low temperatures are expected, including new record-low maximum temperatures. For Southern California, fire weather concerns increase this week. 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.