Severe thunderstorms will be possible Thursday afternoon into Thursday evening. There is still some uncertainty around the severity of the storms, but there appears to be enough dynamics that storms will be severe on Thursday.
This afternoon, storms are currently developing across southern Iowa along a stalled frontal boundary. These storms will remain across southern Iowa, with a few of them being strong to possibly severe. Main threats will be for large hail and damaging winds. Storms from central Nebraska will begin to expand in coverage, and will push into western Iowa early Thursday morning. These storms along with cloud cover will play a role in the development of severe storms Thursday evening.
Looking at the recent high-res models, enough clearing will take place after the morning convection that the atmosphere should be able to destabilize. This will allow for storms to develop across western Iowa.
Storms should initially be isolated across western Iowa, but this will be brief as storms will become linear and will move to the east in a line. If cells remain discrete, then a tornado threat will exist. After storms line out, then the threat will then transition over to a damaging wind and hail threat, with an isolated chance of an embedded tornado. However, once again, all of this will depend on how things evolve later on this evening into Thursday morning.
Another big concern will be for moderate to heavy rainfall across northern Iowa. Rainfall rates as high as one to two inches per hour at times may lead to flash flooding and rises in area rivers. The northern Des Moines river basin and upper reaches of the Cedar basin including the Winnebago river may exceed flood stage by later in the week.
Make sure to follow us on Facebook, Twitter and Instagram for all of the very latest developments as we will be tracking the latest all evening and during the day Thursday.