Above is the latest severe weather outlook for this afternoon & evening from the SPC. They have upgraded portions of Oklahoma, southeast Kansas, southwest and southcentral Missouri and northwest Arkansas to a "Moderate" risk of severe weather (as shown by the red shaded area). This means that areal coverage of severe thunderstorm activity is likely to be more widespread in these areas. A similar risk upgrade was made to portions of the Ohio Valley.
Tornadoes will be possible with severe storms this afternoon, especially within the brown and yellow shaded areas on the image below:
Very large hail will also be another risk. The greatest threat of very large (i.e., baseball size or larger) hail will be within the pink and black hatched area on the image below:
A cluster of strong to severe storms has already formed this morning along the Kansas/Oklahoma border and is now moving across southcentral Missouri, northwest Arkansas and extreme northeast Oklahoma. This activity will continue to progress East/Southeast into adjacent portions of Missouri and Arkansas this afternoon, with damaging winds and large hail the greatest threats.
By mid to late afternoon, thunderstorms are expected to develop in Western portions of the Moderate risk area from southern Kansas into western Oklahoma. This activity will move and/or develop Eastward into adjacent areas of southcentral & southeast Kansas and central and eastern Oklahoma by late afternoon and into this evening. Very large hail, damaging winds and tornadoes will all be possible with this activity.
An outflow boundary is currently flowing southwestward from the thunderstorm complex along the Arkansas/Missouri/Oklahoma border areas, and is moving toward the Tulsa area (thin blue line circled in red on the radar image below):
Updated radar image showing outflow boundary as of 12:55 PM CDT:
As of 12:50 PM CDT, the Western end of the boundary has become nearly stationary over south Tulsa, while the Eastern end continues to move slowly Southward.
This boundary is likely to become a focus for new thunderstorm development this afternoon across northeast or east-central Oklahoma and west-central or northwest Arkansas and will have to be closely monitored. Any cooler, more stable air that flows into northeast Oklahoma or northwest Arkansas behind this boundary could also influence the severity (i.e., decrease the severity) of any storms that may move in from the West later this afternoon. We'll have to monitor for both of these possibilities this afternoon.
Meanwhile, in north Texas, thunderstorms are developing along the nose of a surge of instability just off the surface level, near the Dallas/Ft. Worth area currently. A Severe Thunderstorm Watch was just issued for this area, valid until 5pm CDT:
Large hail will be the main threat in this area this afternoon. The storms will also move very slowly, which could result in a flash flooding threat over time.