Isolated thunderstorms will be possible across far southwest Oklahoma this afternoon just to the north of a stalled out frontal boundary. Shower and thunderstorm chances will increase across the entire area late tonight and early Sunday as an upper level storm system moves east into the central plains. Afternoon heat index values will rise into the 100 to 105 degree range across far southeast Oklahoma this afternoon.
Widespread showers and thunderstorms will continue Sunday as the upper level storm system continues moving east and a cold front approaches from the north. A few of the storms may be strong to severe, and locally heavy rainfall will also be a concern. Thunderstorm chances will end Monday following the passage of a cold front, but an upper level disturbance moving southeast in the northwest flow aloft will bring low thunderstorm chances back to the area late Wednesday night and early Thursday.