Long Range Forecast (December 15 – January)

***I am only adding a small update to Jeremy’s 12/15 post. Because it is an extensive post and our weather is benign, I will let it breathe another day.***

Good weekend for holiday travel and shopping. I’m closely watching the possibility of accumulating snow Monday – Tuesday. Look for a detailed forecast in the blog on Saturday. Thanks.



***Watch WISN 12 News at 5, 6, & 10pm for the latest weather information!***

Thank you for stopping by the Weather Watch 12 Blog!  In today’s blog we’ll look ahead at the long range forecast for the rest of December and through January.  The long range forecasts that we provide here in the blog are based off the LRC.  If you are new to the blog or need a quick refresher, here are the basics of the LRC.

The ‘LRC’ which stands for Lezak’s Recurring Cycle is a weather pattern theory based on the following:

  • A unique weather pattern sets up every year between October 1st and November 10th
  • The weather pattern cycles, repeats, and continues through winter, spring and into summer. Identifying the cycle length helps tremendously when making long range weather predictions.
  • Long term long-wave troughs and ridges become established and also repeat at regular times within the cycle. These dominant repeating features are a clue to where storm systems will reach peak strength, and where they will be their weakest.
  • The LRC is a winter-long pattern! There is a pattern! It isn’t just one long-wave trough, storm system, or ridge. It is a sequence of troughs and ridges that are cycling across the Northern Hemisphere.

To put this in very simple terms, the weather pattern that occurs in October and November repeats thru the Winter, Spring, and into the Summer. The cycle length will vary each year. I’ve seen cycles of 42-46 days, 60-62 days, etc. The easiest way to view the LRC is to look at maps in the middle of the atmosphere, the 500mb level. The 500mb level is really a good spot to analyze the trough(lows) and ridge(highs) positions to help determine the long term longwave ridges and troughs. At the 500mb level you also don’t have to factor in friction or surface moisture. The theory can be translated down to the surface(where we live), which we do in this long range forecast.

Here is a video of our winter forecast based on the LRC, this was issued November 23.


After this year’s ‘signature’ storm hit the area again(previous time was October 26) over this past weekend the cycle duration and pattern are now very clear.  This year’s cycle lenth is around 46-48 days.  Now that the cycle duration is known and also the location of the long term longwave ridges and troughs we can start to project forward and make accurate long range forecasts!

We’ll break most of the long range forecasts into week increments. 

December 19-25

This period is right around the corner, and parts of it are currently in our 7 day forecast.  Back on November 4 an upper level trough dove into the Great Lakes, followed by a push of colder air.

This trough should provide chances of snow around December 20, likely our best chance of accumulating snow in this time window.  Once the trough slides east, another pocket of cold air should drop in for 2-3 days.

At this point I do not expect a major storm on Christmas Eve or Day.

December 26-January 1

The first couple of days of this period may be quiet, but then closer to the New Year the weather should become more active.  Back in mid-November a series of upper level troughs moved into the northern Plains and upper Midwest.  I expect this feature in the cycle to once again fall into the favored long term longwave position.

Below is the 500mb map from November 13, 2010.  This shows the general trough with the upper lows over the Plains and parts of the Midwest.

Now fast forward 47 days.  This should mean a moderation in temperatures as the trough nears, and then a chance for a storm system around December 28-30.  This would likely bring a chance of snow to the region, and then a push of arctic air to end the month and ring in the New Year!

If you are traveling to the Rose Bowl in southern California around this time to watch the Badgers, I think the trough and cold in the central U.S. should allow for the West Coast ridge to nudge into California and provide for nice, warm weather! 

January 2-14

What I expect to be an overall active month of January should start out with the chance of a clipper moving by around January 3-4.  It may be slightly stronger than most, so some snow is possible.

The part of the pattern that will repeat during this time window could bring a major storm to parts of the country.  Here’s why.  Back on November 22 a strong southwest flow developed, with several waves riding northeast along the flow.

Below is the 500mb map from November 22 showing the southwest flow.  

Over a 5 day stretch from November 21-25 Milwaukee picked up over 1.25″ of rain.  I again anticipate several waves to move into this favored long wave position beginning around January 5-8.  

I think this part of the pattern has the potential to produce an ice storm in parts of the Plains or southern Midwest.  Often the very cold air at the surface will get trapped under a southwest flow like the one shown above.  After living in Kansas City for several years, where ice storms occur more frequently, the map above to me combined with pieces of energy flowing along it hints at this possibility. 

Farther north around Milwaukee, I think this will bring us rounds of precipitation.  If the main piece of energy can once again eject into the long term longwave, I think this period could produce a major winter storm around southeast Wisconsin. 

Below is the 500mb map from November 25 when the strong upper low was over the Dakotas.

As this storm exits, another chunk of arctic air should drop south.

Second Half of January

The second half of January may also be very active.  A couple of features stick our during this timeframe.  The first will be how a storm around November 29-30 will track this time through the cycle.  I think this will present a chance for snow in our area around January 15 give or take a day.  Below is how the feature looked back in late November.


The storm that I am really waiting for should arrive around January 27-28, this is in my opinion the ‘signature’ storm of this year’s pattern.  It has already occurred on October 26 and also December 11-12.  This storm could bring a major winter storm to the region.  It will also be followed by a blast of arctic air that in my opinion will bring the coldest temperatures of the winter to our area!  The cold would likely stick around into the first week of February.

An average January in Milwaukee produces 15.2″ of snow.  This January I am expecting above average snowfall, with totals above 20″!  I just feel that there are a lot of ‘good’ opportunities this month to catch snow, and this should add up over 31 days to a healthy total.

Back in late November I issued the winter forecast.  One thing that is becoming very clear is that temperatures are going to struggle this winter to warm-up.  December has been well below average, and overall this winter will most likely continue that trend and end up as a whole below average.  When looking at the pattern I should have realized this sooner due to the proximity to both of the long term longwaves that are dominate in this year’s pattern.

The temperature forecast did lean in this direction mentioning at least one month with below average temps and multiple below zero readings.  So if you are hoping for drastic change to warmer weather you may want to temper your expectations.

If you have thoughts or comments on the long range forecast please ask!  I hope you enjoyed reading and please stop back soon! 

Jeremy Nelson


21 Responses

  1. We’re going to need a pretty solid run of mild days at some point this winter to make that prediction of around average temperatures verify. There’s no way anyone could have predicted a December as bad as this based on the first cycle of the LRC this year.

    • Daniel,

      I’ll address that in the blog that I do today. I certainly did say near average, but should have gone with my gut and what the LRC was telling me and went below average temps. The position of the long term longwaves will not allow a lot of warming this winter, especially with a deep snowpack to our northwest now.

      That is why in writing the forecast up I said, multiple below zero readings, at least one month below average temps. More snow and cold than last winter. If I was leaning the other way I would have left that language out.

      It would be nice to do the winter forecast a couple weeks later since the pattern is almost rock solid and confidence is much higher then. But then we are into winter:)

      I will get the forecast posted this evening. I’m working on it in pieces this afternoon. Hopefully by 7:30!


      • Jeremy,

        I was wondering what your thoughts and views were on this constant blocking pattern that keeps setting up every winter?

        Why does this high pressure system persist over Greenland plunging frigid air down as far south as Miami? And what causes it?

        And has this happened in the past? I don’t recall such an event happening 10 years ago.

  2. Great work Jeremy, so when do you think our next chance of a 6 inch plus snowfall is? Do we have to wait until the next time the forecast bomb comes back? Do other areas on the planet say Europe or Asia experience the same cycle as we do? In general how come it takes a ridge and trough so long to cycle around the planet, why not every 10-20 days?

    • We believe that the LRC is a theory that works with the Westerlies in the Northern Hemisphere. So, it should work in Europe and Asia.

  3. After reading the words “good chances for snow” multiple times, you got me excited! 🙂 let’s hope it holds true!

    • Bryan,

      There is a ton of potential in January for snow lovers!


  4. Jeremy, yesterday I looked back through November’s patterns and came up with a forecast of when I thought storms would come through for Dec and early Jan. Your forecast confirms the dates I picked. It’s so awesome that the LRC helps a rookie like me make long range forecast. Many thanks to you and Gary for teaching us the ways of the LRC.

    • Steven,

      The great thing about the LRC is that anyone can follow along and try to make their own forecasts. Hopefully the one I made is close:)


  5. Thoughts and views on this constant blocking pattern that keeps setting up every winter? A product of the LRC?

    Why does this high pressure system/warm pool of air persist over Greenland plunging frigid air down as far south as Miami? And what causes it?

    And has this happened in the past? I don’t recall such an event happening 10 years ago.

    • Dave,

      It seems like many times over the past 5 years we’ve had stories on the news about freezes in Florida. This past Tuesday was pretty crazy in Miami, only a high of 53! This is mid-December, not mid-January. I don’t think any one feature is a product of the LRC, since the LRC says a unique pattern forms every year. Sometimes highs and lows are more common in places during certain times of the year, like an Aleutian Low.

      I would have to do more research to see if this has happened in the past. Feel free to look around on the archived 500mb charts here



      • Thanks for the link Jeremy!

  6. so when r we getting a 6 or more snow fall? And will it snow on these date Dec. 28, 29 39 31 2010 and Jan 2011?

  7. Thanks for all the hard work, Jeremy. This LRC has really got my attention and gives me the opportunity to make necessary back-up plans that I need to have in place when big snows come around. I like the idea of a more significant snow around New Year’s!

    Don’t know if you saw my comment on the past weekend’s storm, but you had the Reeseville area in line for some of the heaviest snow and you were right on –11″ in areas sheltered from the wind and 16″ to 24″ drifts where there was no shelter from the wind.

    Keep us posted!

    Don in Reeseville

  8. I suspect at least one 40 degree day sometime between Christmas and the 28th as this is the period that lines up with the 4 straight days in the 60s in early November.

    • Daniel,

      Keep in mind there was not snow on the ground then. Snow automatically makes it colder. At least we may get some moderation.


  9. I like the LRC idea. Used to follow it from Milwaukee when you did the Kansas City area version…you were far more accurate that anything else I saw. Did I miss something, or has there not been a follow-up with the more detailed forecast since yesterday?

    • Thanks for reading Adrian! If you followed the LRC blogs from KC I’m guessing you know quite a bit about the theory. Since the blog was posted late yesterday and is pretty in-depth and one that a lot of people were looking forward to, we may just have a quick update later this evening.


  10. Great. When will you start with projections out several weeks ahead of time to start mapping out the effect of the cycle?

  11. Jeremy – the 12Z Euro now concurs with your late year forecast per the 240hr. Eventually, the GFS will figure it out. Shhh…I think I just heard it snore.

    …it is sorta like cheating…

  12. Hi

    Thanks for the forecast. But i have a favor can u please bring good weather for Jan 10th. I am flying to las vegas that day and dont wanna be stuck in the cold and the snow. I am coming home jan 15th so nice weather for that day would be nice too. Just one thing quick how is the weather gonna be in Vegas from the 10th to the 15th of Jan. Any info would be great. Thanks again and wishing you and the rest of the WISN team a very merry x-mas and happy new year.

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