Interesting. Looks like it was a wake low. MLI and DVN gusted to 58mph, Dubuque gusted to 59mph, and across the river from us at Clinton they hit 60mph.
Saw the same pressure fluctuation here on my station. Interestingly, the pressure quickly rose as the precip began around 9:30pm, and then started to quickly fall about a half hour later after the heaviest part of the convection went through. The pressure continued to slowly fall as the light anvil rain fell, and then the pressure very quickly jumped. During that quick pressure jump is when the high winds hit on the very back side of the rain.