South Dakota Red Flag Warning | Effective 04/21/2026 11:48

...RED FLAG WARNING IN EFFECT LATE WEDNESDAY MORNING THROUGH EARLY EVENING ACROSS NORTHEASTERN WYOMING AND WESTERN SOUTH DAKOTA... .Hot, dry, and windy conditions will support widespread critical fire weather conditions Wednesday, mainly in the afternoon and evening. Temperatures tomorrow will range from the 80s to mid 90s with minimum humidities dropping to as low as 10%. Meanwhile, southwesterly winds will increase through the morning as a cold front approaches the region. Sustained winds will be at 20 to 30 mph with gusts of 35 to 45 mph. Scattered thunderstorms are possible across western to central South Dakota Wednesday afternoon and evening. These storms may contain cloud-to-ground lightning and erratic winds with gusts in excess of 50 mph while producing very little precip. This could lead to fire initiation. Conditions will improve Wednesday evening as temperatures fall, humidity rises, and a cold front quickly crosses the area. The National Weather Service in Rapid City has issued a Red Flag Warning for gusty winds and low relative humidity, which is in effect from 10 AM to 8 PM MDT Wednesday. * AFFECTED AREA...Fire Weather Zone 328 Perkins County. * WINDS...South 10 to 20 mph with gusts up to 30 mph. * RELATIVE HUMIDITY...As low as 15 percent. * IMPACTS...The combination of gusty winds and low relative humidity would produce critical fire weather conditions.