It's certainly rather intriguing.
One thing I would really like to know too is if we're (we're as in climo stations) hitting temperature thresholds of 80, 85, 90+ much easier now compared to historical averages (meaning with lower 925, 850, 800mb temperatures) or maybe we are just achieving stronger mixing. Actually what would be cool to know is are we averaging warmer 925/850/800 temperatures overtime...when assessing climate change all the focus is on surface temperature anomalies but is this a product of a lessened ozone layer resulting in greater shortwave radiation, a product of a warmer low-level airmass, both, or other factors.
The low-level airmass aspect could be quite intriguing when taking into account the origins of these airmasses. If the Southwest/southern Plains region is experiencing earlier heat and big heat...well it's more likely we would see the same...or at least a higher probability for some type of big heat (whether it be brief or longer duration) very early on.