UPDATE: 11:08PM, Threat of flooding increasing with line of thunderstorms near Kansas-Oklahoma border. Radar indicates that already three inches has fallen in spots. Given the earlier heavy rains, this is more than enough to cause flooding. Some flooding has already been reported in Ponca City, OK.
UPDATE: 10:20PM, flash flood warning already issued for the areas circled.
As much as 4" expected in southern Kansas. Now, don't take this too literally...this can shift 30 mi. or so in any direction. However, flooding is especially dangerous at night..and given the saturated ground there will be areas of flooding late tonight and tomorrow morning. Click to enlarge.