Overnight, the Storm Prediction Center has trimmed down the slight risk for today. The only portion of the it now includes is the far northern portion of the state.
From the image above you can see that only the top two tiers of counties are included in this slight risk. We have mentioned this the past few days now how there would be a strong enough cap that would limit storm potential. This still looks to be the case. Capping and ridging aloft will inhibit thunderstorm development until 9pm. After 9pm, the low level jet will begin to kick in, and this will provide the lift needed to form storms.
The main risk with storms across northern Iowa tonight will be large hail with an isolated damaging wind threat. The SPC has also highlighted an area of 2% risk for tornadoes as shown in the graphic below.
Right now the tornado potential is very low, but as the surface low moves to the northeast, it could be possible to have a brief spin up, and this threat will be very isolated. With that being said, today’s threat will be large hail. Storms will also be possible across the rest of the state by tomorrow morning, and a few of these may contain some hail. This is why a 5% hail risk has been issued for central and western Iowa. The severe threat then pushes east tomorrow, as central and eastern Iowa are under a slight risk. We will have an update on tomorrow’s potential later on this afternoon. We will continue to monitor the very latest, and will bring you any updates to our Facebook and Twitter pages, as well as right here at Iowachase.com.