The New Weather Pattern & The ‘LRC’

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Thank you for stopping by the Weather Watch 12 Blog!  Today’s blog will be dedicated to the reintroduction and explanation of a unique weather pattern theory…the LRC. I love talking about the weather and know that many who follow this blog now and in the future will find what I’m about to explain as fascinating.  The Weather Watch 12 Blog is the ONLY place to find this information in Milwaukee!  

The most common question that I am asked has to be, “What will this winter be like?”. 

The theory that I’m about to discuss may hold the key to that answer months in advance!  Before we discuss the theory, let’s take a look back at how I learned about the LRC, and some history of the theory.

Back in 2006 I started working at a tv station in Kansas City. The Chief Meteorologist at my station was Gary Lezak and the weather producer, also a Meteorologist, was Jeff Penner. When I started they introduced me to a weather pattern theory they discovered years ago. Once the theory was first explained to me I was the biggest skeptic since it sounded too good to be true and really unbelievable. I was told to follow along for a year, learn, and then form my opinion. I agreed since I was really more curious than anything. After just 3-6 months of watching and studying the pattern, it became very clear that there really was something to this theory.

Back in 2006 the theory was not named, today it is called the ‘LRC’ which stands for Lezak’s Recurring Cycle.  Here is what the theory states:

  • 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 lengths of 40-46 days, 48-52 days, and 60-62 days.

Right now the pattern is just forming!  Think of the new pattern as a roulette wheel.  On that roulette wheel are several possibilities such as above average snowfall, above average temperatures, below average temperatures, above average precipitation, etc.  The ball is spinning around as the new pattern forms, and it won’t land until sometime in November.  Once the ball lands, our pattern is set for the next 9 months or so!

So how is the pattern determined.  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 analize 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. 

Below is an example of a 500mb map.  This is the 12Z NAM initilization for 7 a.m. Tuesday.  I labeled the troughs and ridges to give you an idea of some of the large features that we track when the pattern is setting up.  Could one of these features be a key to this year’s weather?

What happens at the 500mb level can be used to translate the weather down to the surface(where we live).

Determining the cycle length each Fall really holds the key in using the LRC to forecast into the future. A very good idea of the cycle length is usually determined anywhere from late November thru December. Once the pattern goes thru its second cycle a period of days can be placed on the cycle length.

Once the number of days is determined for the cycle.  Individual storms and events can be picked out and forecast weeks in advance!  Sound too good to be true?  If you followed the blog last winter you would have seen the theory and long range forecasts in action.

Look for updates on the pattern in the coming weeks, and the Winter Forecast right here in late November!  Until then, I would love to hear your thoughts and questions on the LRC!  Just post them to the comments section of the blog.

Have a great day!

Jeremy Nelson

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9 Responses

  1. October is off to a cool but dry start. If this becomes part of a pattern we could enjoy a week or two 40 some days from now with mild and dry weather, that would be nice. The less snow this winter the better!

    • Bryan,

      Keep in mind the jet stream is in Canada, keeping most of the energy well north of our area. When that drops south in the winter the weather will be much different. That is why we need to focus on the long term longwave ridges and troughs. Not just individual days right now, or a single week of weather. Good question though.

      Jeremy

  2. Bryan, I couldn’t disagree more the MORE SNOW this year THE BETTER!! I would prefer it in the Northern part of the State though 🙂

    • Dan,

      I thought last winter was okay…enough snow, but not too much.

      Jeremy

  3. Interested.

  4. Jeremy,

    So last years pattern affected our summer weather this year? If so, what was the pattern so I can see ahead what next summer might be.

    • Denise,

      A brand new never before seen pattern is forming right now. The pattern that gave us a wet summer at times, was with us since October of 2009. Many factors play a role in the results at the surface(where we live). So the key is identifying the cycle length, and where the long term longwave ridges and troughs are located. Hopefully this isn’t too confusing. But just ask more questions. The quick answer, this past summer’s pattern is now gone, and a new one is forming.

      Jeremy

  5. Since droughts are self perpetuating, how does the lrc handle this. SW IN according to the NWS is going to switch from a drought to above normal precip within 50 days. I think the NWS is way off on this area. Your thoughts, please. –Kerry Dean, NWA

    • Kerry,

      When it comes to tackling prolonged events like droughts here is how I view the LRC’s role in forecasting changing conditions. First, the pattern is forming right now…I can’t comment or make a forecast for what will happen 50 days down the road at this point. I first need to see where the long term longwave ridges and troughs align, and then determine the cycle duration. Once these factors are determined, then forecasts for precipitation and temperatures over a long range can be made.

      This past summer I used the LRC to make a long range forecast for southeast Wisconsin and then compared it to the CPC outlook. The forecast I made called for above average temps, their’s below average. The summer was above average(every month) in Milwaukee. I was forecasting around average rainfall…that missed. Mainly due to 2 days during the summer, one produced the 2nd wettest day in the city’s history…over 5.00″ of rain. However, I did pin down back in May when the most active period of severe weather would occur in our area during the summer, and that was correct. Overall the LRC is meant to pick up on the large scale pattern, and then translate that down to the surface.

      So things like convection and lake effect snow – microscale events – can throw off the best long range forecast. But generally if you look at the upper level pattern when these types of small scale events occur and compare it to the previous cycle(s) the flow still matches. It’s just the surface result that was slightly different. I think summer forecasts are the toughest with the LRC, mainly because the flow is so weak, and the pattern begins to breakdown.

      Jeremy

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