Weekend Mess & The Pattern Repeats

***Watch WISN 12 News for the latest on the weekend storm!***

Thank you for stopping by the Weather Watch 12 Blog!  The storm that will bring us rain, a mix, and snow this weekend is slowing pushing toward Wisconsin.  Now that the storm is only hours away from beginning, let’s answer some of the tough questions like how much snow, and where will the heaviest snow pile up.

The key to any snow forecast in southern Wisconsin is the storm track.  Our weather team continues to lean toward a slightly more northern track for this storm.  Any slight shift to the south would bring the heavier snow farther south, and increase snow totals this weekend!

On a more northern track the precipitation would likely be rain and a mix, then snow.  Below is a forecast surface map at noon Saturday.  This shows the low in extreme northeast Iowa, about to move into southwest Wisconsin.  At this time we should see rain in Milwaukee with temperatures around 40. 

As the low pushes east it will move somewhere very close to Milwaukee.  Keep in the heaviest snow totals generally line up northwest of the low.  This is what our in-house high resolution computer model was advertising late Friday afternoon.  Check out some of the forecast snow totals in western Wisconsin…over a foot!

For southeastern Wisconsin we need to watch any slight shift in the track very closely!  The difference in 50 to 75 miles would make a huge difference in the snow totals.  Below is the snow forecast that corresponds to the graphic above.  This one shows various cities and exact snow totals through 2pm on Sunday.  Most of the accumulating snow in our area will fall from Saturday afternoon(when the changover occurs) into Sunday morning.

The snow forecast that I showed on the news at 5/6pm Friday almost mirrored this graphic.  I think generally 1 to 3 inches in and around Milwaukee, and then into parts of Washington, Dodge, and almost all of Sheboygan and Fond du Lac counties a band of 3 to 5 inches.

I certainly wouldn’t be surprised to see some slightly higher totals in Fond du Lac county.

Since this is such a tight rope act with the snow forecast and exact low position, please watch WISN 12, check back to the blog, look for Facebook and Twitter updates as the storm nears.

Finally, as many of you know I use the LRC(Lezak’s Recurring Cycle) for long range forecasting.  I am finally to the point where I believe we know the cycle duration based off the storm this weekend.  Our current storm is related to the one that occurred back on October 26, better known as the wind storm.

When identifying the pattern I look at the 500mb, or middle of the atmosphere charts.  Below is the forecast 500mb map for Sunday morning, or roughly 48 days since October 26. 

Now compare that to the 500mb map from October 26.  Incredible!

Now that we know that the cycle duration is around 46-48 days, it will be possible to start making long range forecasts.  I’m hoping that next week I can put together a forecast for the rest of December and into early January based on the LRC.  Remember back to early this week, the LRC allowed us to continually say that the track that the models were forecasting for this weekend’s storm was too far to the east.  Knowing the pattern will give our weather team a huge advantage moving forward.  I hope you will continue to follow along as I discuss the cycling pattern and what it means for our weather!

Have a great weekend!

Jeremy Nelson


5 Responses

  1. Jeremy,

    I’m just wondering why there’s a pretty big difference in your totals with the NWS totals. Where I live, you guys are saying 1.5 inches, but the NWS is saying 3-6, with the higher end likely with theirs (for snow amounts here, I prefer the higher amounts). Also, the NWS says more than a foot for Fond Du Lac while your model says around 7 inches. The NWS is saying that the low will track over N IL and you guys say over southern WI. Thanks in advance!

    • Bryan,

      Outside of passing along the advisories/watches/warnings I’m not sure what the NWS is forecasting. We use our knowledge and experience to make the forecast that you see on WISN. For your area I had you in the 1 to 3 inch band at 5/6pm. The map in the blog was for reference in case anyone was wondering what the RPM snow forecast numbers were. Sometimes with no county lines it is hard to tell so I thought I would post it.

      I’m not sure if our totals were lower than others, but the forecast snow bands I showed were based on the RPM and NAM. The GFS was very poor overall this week, but certainly it may be right now that we are so close to the precip starting. The 00Z models have trended farther south, so I will look things over and adjust our snow forecast as needed. Thanks for the question.


  2. Jeremy,

    I am happy I live close enough to Fondy as it allows the WISN forecasts to actually mean something to me. I’ll admit that, with this storm in particular, I have been paying very close attention to the WISN teams forecast.

    Very exciting times in regards to the LRC. I am mentioning and then explaining the LRC to most everyone I discuss the weather with nowadays. At least half of them do not think I am nuts. The persons who get most of my ramblings are now very curious.

    I am rooting for the WISN forecast to verify. Enjoy.

    • Josh,

      We are glad you are a part of the blog! When you tell people about the LRC, encourage them to follow along for a year. This looks like it will be our ‘signature’ storm in this year’s pattern.


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