High pressure will be building into the state tonight but another system will be on its heals by Monday. This system will bring a chance of snow and will usher in colder weather behind it.
Snow will begin to move into the western part of the state late Sunday night into early Monday morning. This is also where the greatest accumulations will be. Snow will continue to east throughout the morning hours Monday, but the best forcing will remain across western Iowa. There are some slight differences in the models. As shown above, the high resolution WRF has snowfall accumulations of 2″ to 3″ across west central Iowa.
The NAM is also on board with the greatest snowfall accumulations across western Iowa. The only difference between the WRF and NAM is the NAM has snowfall accumulations under 2″. As of now, it appears that snowfall accumulations will be light with accumulations of 1″ to 2″ across west central Iowa.
Behind this system, much colder weather will be moving into the state by Monday night. Lows will be falling below zero across the northwest half of the state. Winds will also be breezy, which will also add a bite to the air.
With a strong northwest wind sustained at 10mph to 15mph, wind chills will be in the double digits. Wind chills will meet advisory criteria so we likely see an advisory issued by Monday. These cold temperatures will last through Wednesday, before temperatures begin to warm up on Thursday.
There is another system that we will be keeping our eye on that will bring a chance of moderate snow to the state. Right now it is too far out and due to model differences, we will not be talking specifics.