Here are two cross-sections (colors are total wind speed) across Colorado, Kansas, and Missouri. These show that the low-level southerly jet increases from 34 kt just above the surface (at 00z, not shown) to about 56 kt or 58 kt in a span of 6 hours on Wednesday evening. I have always found it amazing that as the surface temperatures cool, the winds pick up, but above the surface, not at the surface, in these special situations.
SPC upgraded to 30% for wind on Wednesday