Weekend Storm Looms

***Watch WISN 12 News for the latest on the snow forecast!***

Thank you for stopping by the Weather Watch 12 blog!  The weather is about to get very exciting in southeastern Wisconsin!  If you love snow, I think you will not only like Thursday, but the potential storm this weekend could be our first major storm of the winter season!

For the past several days, if not longer, I have been talking about how I was NOT buying the track that most of the models were showing for the upcoming weekend storm.  My thoughts were based on a weather pattern theory that I use called the LRC, or Lezak’s Recurring Cycle.

If you are new to the blog, just click the link below to view the winter forecast story that I did back in late November.  In that story I outline what the LRC is, how it can be used, and what it means for our weather this winter.  Of special note is the map that I show discussing the wind storm that blew through back on October 26, and how that part of the pattern could bring us another large storm based on the position of the long term longwave trough.


Now a quick look at how the 00Z computer models have started to latch onto a much more western track for the main area of low pressure.  Keep in mind I expect there to be a few more changes before this storm is set, but this is along the lines of the track I had been expecting over the past few days.

Let’s start with the GFS(Global Forecast System), the model did a complete 180 based on previous runs.  Below is the surface map at 00Z Saturday.  That is all snow across southeastern Wisconsin as the surface low tracks just south of Chicago.

The 00Z NAM model has the low slightly farther south, but still in a very good position to bring our area the biggest snow so far this season.

If you compare the GFS to the map in the previous blog entry, the change in track is really amazing.

Without knowing about the LRC or the overall weather pattern, and having experience using the LRC for the past 5 years I would have fallen in line with any other forecaster and been at the mercy of the models.  Since we have seen this feature before, and knowing its favored location within the long term longwave it is clear that this has the potential to be a major winter storm for our area.

With that said some questions still are unanswered.  Back in October the upper low tracked over Minnesota.  If the models continue trending west this could end up bringing in warmer air and the possibility of some rain, a mix, then snow.  If you remember back to around Christmas last year, that storm took a westerly track following its October version, and left southeastern Wisconsin with almost all rain.

So if you love snow, feel free to get excited.  At the very least you should see 1 to 2 inches on Thursday, maybe 3 inches in a few spots.  Then the potential for a bigger storm this weekend!

Stay with Weather Watch 12 for the latest on WISN 12 News, on Facebook, Twitter, and on course right here in the blog!

Jeremy Nelson


14 Responses

  1. WISN Storm Team,

    Looking at GFS model and the European model, there has been a significant shift to the west. Do you think that the later runs will continue to move it further west…possibly bringing a mix into our area at the start? Does the strom still seem as stong as previously thought? It seems like this storm has everyone baffled. Looking forward to hearing your response.

    • Kosta, it is possible for it to trend even farther west. I think the models will show a stronger storm in future runs. I wouldn’t say we have been baffled since we have said the entire time it should and will track farther west. Our focus today will mainly be on the snow for later today. It will likely cause a few issues on the roads.


  2. Jeremy- Could you post a reply to this when you see the 12Z models and let us know what you see? I see the NAM FOUS for 12Z does bring in .28″ of QPF in the 60 hour range but also has heights up to 540…rain/snow mix??

    • Ron,

      12Z NAM has the low even farther west, not surprised. Go back into the winter forecast that I did, and look at the map showing the feature that produced the wind storm. The low tracks close or west of our area, and it looks like that may occur again. A rain/snow mix is possible, but there will be some snow too. When I did the winter forecast I said precipitation when referring to this feature, since the track back in October was to our west so anything from rain to a mix to snow could be possible with these stronger storms.

      The new NAM also has a stronger low pressure area over the Great Lakes, something I thought the models were missing. This is certainly the wind storm feature. The question now is how much rain, mix or snow will we get. One thing is certain, there will be a lot of wind once again by Sunday!

      I will admit, I’ve used the LRC for 5 years, but even for me it is tough to stick by what I know should happen based off previous cycles or the position of the long term longwave when no model is showing what I think will happen. At least know the real track is showing its face:)


  3. NWS now saying 34 and rain and snow for Saturday during the day as the Low is now passing right over us so it looks like the latest model runs 0600 have moved it north, that having been said I would be suprised if we didn’t get at least 6 inches. Jeremy any chance that we get a monster 12-16 inches out of this one, or would that require more Gulf Moisture? I am thinking back to 2008 when we had two 12+ inch snowfalls.

    • Bryan,

      Outside of talking about advisories or watches/warnings I never look at the NWS forecast or discussion. I use different methods that have proven successful, and I would rather live or die by my own forecast. Our weather team always makes their own forecast, and we often discuss what we think will happen with each other. Usually this is why our message stays consistent.

      To get a huge snow out of this the surface low should track to our south. Certainly that is in question/doubt right now.

      Here is the 500mb map from October 26


      Now the NAM 500mb forecast


      • Jeremy- The 12Z GFS is quite interesting. We would be clobbered if that pans out…agree?

      • Ron,

        I believe the 12Z NAM more than the GFS right now.


  4. It sure will be interesting to see how this potential storm develops. I’ve checked several other weather sources and it seems this storm has everyone baffled at this point. There are a lot of differing opinions out there as to what this potential storm will bring to WI this weekend, all the way from no precipitation at all to heavy snow. One of the other Milwaukee stations is predicting 1-2″ max for the state on Saturday.

    It will be great when the storm track can be determined with possible snowfall potential. Right now it’s very up in the air. Can’t wait to hear the final possible track and snow potential probably tomorrow sometime. Thanks for the work you do, WISN is a valuable resource for weather info.

    • Cliff,

      Thanks for reading. I think today is still too early to put totals out for the weekend since the rain/snow line may be very close and the track continues trending west. Not surprised on the track based on October 26. This reminds of how the storm around Christmas last year behaved, just like its match back in October.


  5. What’s the point on even following these models since they can’t hold on to one solution? Now the southward bias 12zGFS is almost close enough to give us some rain. What is your in-house model saying about this? That seems to outperform everything else.

    • Daniel,

      I’ll look at that when I get to work around 2pm. Today will be very busy at work with the snow moving in. Look for updates on WISN 12 later this afternoon. You are correct, sometimes the models try to lead us into believing something that we know should not be true. This is a good example why it is tough to get too excited about one specific storm track on any model more than a day or two out.


  6. Really hoping for a good snowfall out of this storm. Thanks Jeremy and the rest of the WISN crew for keeping us up to date on this winter storm. You guys do the best job at predicting these storms then others in my own opinion. Make it snow! 🙂

    • Nicole,

      We are very confident on snow later today and this evening. So you will get some snow today if you are in southeastern Wisconsin. The weekend is still a tough call. Thanks for following us on the blog!


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