The reason is a high percentage for tornadic development, and a noticeably stronger warm front than what we saw yesterday. Temperature gradients along I-80 in southern Iowa are 15 degrees.
This indicates the strength of that frontal boundary. With tornadic development bulls eyed for the “triple point’,” the best chance for tornadoes lies along its track from Des Moines to Waterloo this afternoon.
Rapid development of supercells also greatly enhance the threat of large hail. With these two factors in mind, it is only a matter of time before a tornado watch is posted for parts of Iowa this afternoon.
As the storm system moves east, storms will linger in eastern Iowa until the cold front sweeps through. Heavy rain should not be much of a concern, but that’s something I’m paying little attention to.
It’s virtually no doubt chase teams will deploy across central and eastern Iowa today, we’ll do our best to keep you updated from the field.