Yea I’m not sure how snowpack can be ignored. I will never forget the summer of the 98/99 snowfall season. There was still 4 feet of consolidated snow at 3,200 feet at the end of July. Many places never melted out.

4000 J/kg surface based CAPE in Illinois is pretty impressive for this time of year. Other models generally have less though.

There's definitely a correlation with the snowpack and with how fast things dry out in the spring/summer. All other things being equal a stronger snowpack provides some safety netting.