The severe weather outlook was expanded more to the South and Southeast with the midday update, as shown by the yellow shaded area on the above image.
An outflow boundary, which is a boundary produced by cool air flowing out of thunderstorm activity, has moved South to near the Kansas/Oklahoma border as of midday. This boundary is likely to cause the most unstable air to pool to its South, over Western and Central Oklahoma. As a result, the greatest potential for very large hail (over 2 inches in diameter) has been shifted South of that boundary, and now includes Oklahoma City and Enid, as well as the Tulsa area (red and black hatched area on the image below):
Severe storms will still be capable of producing large hail over southern Kansas, it just appears as though the highest risk of particularly large hail has now shifted South a bit.
The remainder of the thinking from the earlier outlook remains intact, so please see that post for additional details on the central Plains risk.
In the Mississippi Valley and Deep South, the risk area has been expanded (yellow shaded area on the top image) to include isolated to scattered severe storms that may develop along a stationary frontal boundary as the air heats up and the atmosphere becomes unstable this afternoon. Most of the activity in this region will diminish around or shortly after sunset.
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