Major Winter Storm Next Thursday?

Confidence is increasing that a major winter storm will strike southern Wisconsin later this week (most likely Wednesday-Thursday). Many models used in forecasting are beginning to trend toward a snowy solution. If these forecasting tools continue to trend in this fashion, SE Wisconsin could be in store for a heavy snow storm. There is also potential for a blizzard, although the heavy, wet snow will make it difficult to create widespread blowing snow.

One model used in forecasting is the GFS. Let's take a look at that model first. Below is the 12z run:

Image from NWS

As you can see, this run is showing a narrow band of heavy snow from eastern Iowa to SE Wisconsin. The 5400 thickness line is also below us, which is a good indicator that precipitation above that line will be snow (this is not always the case, and the 5400 line is not the only tool used to forecast who gets snow and who gets rain).

Here is the 12z GFS snow forecast:

Image from InstantWeatherMaps.com

Again, you need to look at soundings and other charts to identify where the heaviest band of snow will be, but the map above is indicating the potential for 6+ inches of snow.

The next model that is used is the ECMWF/ European model. Let's take a look at its 00z run. This certain run is showing the 5400 line cutting through extreme SE Wisconsin-- this is one factor which I am uncertain about. Extreme SE Wisconsin has the potential to have a rain/snow mix throughout the entire event, which would result in very little snow accumulation there. 

Image from Wunderground.com

There are many other forecasting models that are used, but I will not be mentioning them in the post. Stay tuned for more updates, watch the news, and follow the latest NWS updates.

-Chris