Low pressure is forecast to develop and move into the Great Lakes Sunday and Monday. Mild air will advance toward the eastern Great Lakes, running up and over the denser cold air currently in place at the surface. This will create the potential for significant icing across the Ohio Valley and eastern Great Lakes, eastward into the Mid Atlantic states.
Precipitation will likely break out Sunday across the mid west and spread eastward across the region Sunday Night. The precipitation could begin as a period of snow. Some snow accumulation is possible, especially across central and northern Lower MI, eastward to northern NY state.
At this time, it looks like a broad area of icing is possible across much of the region with the potential for significant icing in some areas.
There is some uncertainty regarding the thermal profiles across the region with this event. This will have a significant impact on precipitation type and duration of each type. Major travel impacts are possible. Some damage to trees and power lines will be possible as well.
Milder air will overspread the region from west to east late Sunday night and Monday. The ground temperatures are very cold and it could take some time for them to warm above freezing, even after the air temperature exceeds 32 degrees. By Monday afternoon, temperatures should warm up sufficiently to allow most locations to change to plain rain, ending the icing threat. The exception will be across the north and east where cold air will linger longer.
This is potentially a high impact event. Stay tuned for updates to this forecast as the event approaches and forecast details become more clear.