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Thank you for stopping by the Weather Watch 12 Blog! Back on November 23 I issued the winter forecast for southeastern Wisconsin based on the LRC. In that forecast I mentioned a certain part of this year’s weather pattern could bring the potential for major winter storms to our area. That part of the pattern is about to return!
Before we talk about the potential for a ‘bigger’ storm, let’s focus on the snow chance that heads our way for Thursday. The quick moving storm system for Thursday will be what we call an ‘Alberta Clipper’. These typically bring our area light precipitation, and I expect that to hold true again on Thursday.
Since we are in the winter though, any type of light amounts of precipitation can translate into snow, and really anything that sticks can cause some headaches. On Thursday afternoon, I expect light snow to develop fromwest to east across southern Wisconsin.
Below is the forecast surface map from the HPC for 7pm Thursday. This shows light snow in our area as the main area of low pressure is well to our northwest.
This snow will fall during the evening commute, so there could be some issues or extended travel times tomorrow. Snow totals across our area will likely fall into the 1 to 2 inch range in many locations, but I could also see some areas staying under 1 inch, and a few getting close to 3.
Below is the snowfall forecast that I showed on WISN 12 News This Morning on Wednesday. This is from our in-house high resolution computer model. This model did very well with our snow this past weekend!
Once this quick clipper moves by, the focus will be on the weekend. Mark has been talking about this storm in the past couple of blog entries. I want to talk more about how this fits in the overall pattern and this year’s LRC. After looking at the pattern and what lies ahead, I think this storm may be our ‘signature’ storm of this year’s pattern.
So where have we seen this before? Let’s look back to October 24 and the jet stream, or 300mb level. The shaded areas on the map below highlight where the strongest winds, or jet streaks, are located. Of note is the very strong jet stream winds that were about to crash into the Northwest Coast.
These strong winds helped in forming the huge windstorm that hit the Midwest back on October 26!
Now fast forward roughly 47 days to this coming Friday. The forecast 300 mb map below is from the 6Z NAM(North American Model) showing another intense jet streak with very strong winds approaching the Northwest Coast. This feature is almost identifcal to the one back on October 24.
Strong jet streaks can help to build ridges and troughs, in turn leading to storm systems at the surface. If you would like to read more about jet streaks and their importance just follow the link below. It gets a little technical, so that is why I’m just supplying the link.
Since I believe this to be the repeat of the feature that produced the wind storm, I’m once again expecting a large and intense storm to form over the weekend. As we have been discussing the track of the storm will be key. It may mean the difference between a foot of snow, or an inch of snow. Or it could mean the difference between rain and a mix or all snow. By looking back to the past, the position of the long term longwave does offer us some clues.
With that said, I think the current position of the GFS track, shown below, is too far to the east at 6am Sunday.
In order to get the track to shift, we would need the storm to slow down or strengthen. No matter if we get hit by the storm or it stays east, it looks to get very windy and cold on the backside of the storm.
Make sure to stay with Weather Watch 12 for further updates on Thursday’s snow, and also the potential for a weekend storm!
Have a great day!