Red Flag Warnings are in effect Friday across northeastern Wyoming, southeastern Montana, western South Dakota and southwestern North Dakota.
Southwest winds gusting 40 to 55 mph, humidity as low as 13 percent and unseasonably warm temperatures create critical fire weather conditions.
Any fires that develop will spread rapidly. Outdoor burning is not recommended.
A strong cold front arrives Friday evening, shifting winds to the northwest.
Northeastern Wyoming and Western South Dakota
NWS Rapid City says the warning remains in effect until 11 p.m. MDT.
Where: Northern Foot Hills, Butte County area, Northern Campbell, Southern Campbell, Crook County Plains, Weston County Plains and the Wyoming Black Hills.
Winds: southwest at 25 to 35 mph, gusting to 50 mph.
Humidity: as low as 13 percent.
Winds turn northwest after midnight as the front moves through.
Some showers may accompany the front, but no widespread wetting rain is expected.
Southeast Montana and Northern Wyoming
NWS Billings has a Red Flag Warning from noon to midnight MDT.
Where: Northern Cheyenne Reservation, Custer National Forest (Ashland and Sioux ranger districts) and Sheridan County, Wyoming.
Counties: Sheridan (WY), Harding (SD), Big Horn, Carter, Fallon, Powder River, Rosebud and Treasure (MT).
Winds: southwest at 20 to 30 mph, gusting to 45 mph, with gusts to 45 mph continuing from the northwest through much of tonight.
Humidity: 14 to 20 percent. Highs: 75 to 85 degrees.
The most dangerous conditions are southeast of a line from Baker, Montana, to Sheridan, Wyoming.
Southwest North Dakota
NWS Bismarck has a Red Flag Warning for Slope and Bowman counties until 8 p.m. MDT.
Winds are south at around 20 mph, gusting to 40 mph.
Afternoon humidity drops to 15 to 25 percent.
Central Wyoming
NWS Riverton has a Red Flag Warning for Johnson County (Casper BLM) from noon to 8 p.m. MDT.
Southwest winds of 30 to 40 mph gust to 55 mph, with humidity as low as 20 percent and highs in the upper 60s.
The cold front moves in after 6 p.m., bringing northwest winds of 20 to 30 mph with gusts to 40 mph.
Sharp Change Ahead
NWS Rapid City says the front crosses northeastern Wyoming and the northwestern South Dakota plains between 9 p.m. and midnight MDT.
It reaches the rest of western and south-central South Dakota between midnight and 4 a.m. MDT Saturday.
Sunday highs are forecast in the 40s to near 50.
Fire Safety
Do not burn outdoors, and avoid anything that could spark a fire.
Report fires right away, and know your escape routes.
Local forecasts and alerts: NWS Rapid City, NWS Billings, NWS Bismarck and NWS Riverton.
