The National Weather Service in Norman, Okla., has issued a Severe Thunderstorm Warning for northern Clay County effective until 12:30 p.m. Tuesday, May 21. At 11:25 a.m., the NWS detected a severe thunderstorm approximately six miles northwest of Petrolia, moving northeast at 45 miles per hour.
The fast moving storm is capable of large, damaging hail up to golf-ball size and winds in excess of 60 miles per hour.
A Tornado Watch remains in effect for Clay County until 7 p.m. Tuesday, May 21. The Tornado Watch also includes Wichita and Archer counties.