Tornado watch issued for 29 Oklahoma counties until 4 a.m.

Alfalfa, Beaver, Beckham, Blaine, Caddo, Canadian, Comanche, Cotton, Custer, Dewey, Ellis, Garfield, Grady, Grant, Greer, Harmon, Harper, Jackson, Kay, Kingfisher, Kiowa, Logan, Major, Noble, Roger Mills, Tillman, Washita, Woods and Woodward counties are under the watch until 4 a.m., according to the weather service.

A severe thunderstorm that prompted tornado warnings in Texas was moving into the southwest corner of the state near Altus about 9:30 p.m.

Severe thunderstorms are also developing in the western parts of the state near Elk City and Clinton heading east at 30 mph.

The main threats tonight for western Oklahoma include the possibility of very large hail, damaging winds up to 70 mph and isolated tornadoes, forecasters said.

As a storm system moves eastward from the southern Rockies tonight, the risk of severe weather will increase. A cold front will end the chances of severe weather, after it sweeps eastward across western and central Oklahoma tonight and early Friday, according to the weather service.