The Storm Prediction Center in Norman, Oklahoma has posted a moderate risk of severe weather over a large area of Iowa for today. Very large hail to 2″ in diameter, widespread damaging winds to 80 MPH, and an isolated tornado or two will be possible with the system today.

A southerly low-level jet will feed moisture into the region today with dew points sitting in the upper 50’s to low 60’s. Capping should keep storms to a halt for the majority of the afternoon while the atmosphere and surface heats up, creating instability (nearly 4000 J/KG in west central Iowa), which is a prime ingredient needed for thunderstorm development. A dryline will also be setting up in the Central Plains, which is expected to be overtaken by a southeastward moving cold front in south central Nebraska. Storms should begin firing in this area as the cap breaks. Meanwhile, winds aloft will increase as a mid-level and upper-level trough intersects with bulk shear reaching 40-45 MPH in the early evening.

The environment will become very capable of supercellular development with all modes of severe weather possible. The best chance of tornadoes will be in Nebraska in the evening, before the majority of the convection really begins strengthen thanks to the low-level jet playing with the ample moisture in the area. The storms should continue to the east to southeast and develop into a Mesoscale Convective System. The large hail threat this point will, as usual, weaken slightly while the damaging wind threat picks up.

Stay tuned to the Iowa Weather Network for the latest severe weather information!

Henry Luker | Lead Forecaster
Jeff Wilcox | Senior Forecaster