More Cold on the Way for the Weekend

As we get further and further into the fall season the intrusion of cold air will eventually hold temperatures in the 30's and 20's during the winter months.


We've already had a couple blasts of cold air this season, and it looks like another will arrive for the weekend.

A strong upper level low pressure system will move through Rockies late Wednesday and Thursday.  This will cause a surface low pressure system to develop by early Friday morning east of the Rockies, moving through the Midwest by Friday night and Saturday.

Ahead of the low a very warm air mass will be drawn northward over parts of the Midwest, Great Lakes and Ohio Valley.  Just how warm temperatures get for the Stateline Friday will depend on how far north the warm air is allowed to travel.  Since this system hasn't moved onshore yet, our forecast models are still a bit off on the exact timing, placement and precipitation for the weekend.  As it looks right now, low pressure will move from the Plains into Iowa and northern Illinois by Friday night.  Rain showers are most likely for Friday, with perhaps a thunderstorm or two during the afternoon.  A transition over to a rain/snow mix is possible either late Friday night or during the first half of Saturday. 

A track right over, or slightly north, of the Stateline will yield rain - and perhaps a few thunderstorms - Friday and Friday night with temperatures warming into the mid and upper 50's.  The GFS forecast model is suggesting this for Friday, with a significant cold front arriving early Saturday bringing temperatures down into the 30's for Saturday and Sunday.

The European model, however, has the track of the surface low slightly south of the Stateline and isn't quite as warm for Friday.  It's also a bit slower with the arrival of the cold front and holds on to the precipitation a little longer Saturday morning and afternoon.  But with the precipitation lasting a little longer, this could also mean a better chance for a wintry mix by the afternoon Saturday.


It'll take a couple more days to resolve the timing issues for the weekend, but both models show winds increasing Friday and Saturday, with temperatures falling into the 30's Saturday and low 30's Sunday.