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Thank you for making Weather Watch 12 your #1 source for weather information! Each day you can count on a timely weather discussion right here in our blog. The great thing about this blog is that you can ask questions and leave your thoughts in the comments section. If you are new to the blog welcome, and if you stop by daily it is great to have you back. When I discuss the weather with people in the community the #1 weather question I get is…what does the weather look like 2 weeks from now, or a month from now, will the Spring be warm?
Making long range forecasts is always tricky, but a weather pattern theory known as the ‘LRC’ or Lezak’s Recurring Cycle allows for accurate long range weather forecasts to be made. I have been very excited to introduce this theory to viewers here in Southeast Wisconsin. I first learned about the theory 4 years ago while working in Kansas City. 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. 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. As I have mentioned in previous blog entries, the cycle length this year is about 60-62 days.
Why do I bring up this theory now? Back on January 26 I issued a long range forecast for the entire month of February. I highlighted 2 storms that should bring some exciting weather to our area. The first coming on February 8-9. Before we look at some maps concerning this storm…here is the forecast I made for the week of February 8-14 back on January 26.
In discussing this period, let’s start with a remember when? Looking back into December, a major winter storm hit southern Wisconsin around Dec. 8-9. Madison, WI had around 18″ of snow, and here in Milwaukee about 3″ and also a good deal of rain.
The February version of this storm should return! This does not mean 18″ of snow will fall or it will be more rain than snow in Milwaukee, but what I’m focused on is that the overall pattern will repeat, producing a storm. It would be hard for this storm to be as intense as the December storm, considering the pressure with that storm was the equivalent of a category 2 hurricane! Back in December the jet stream phased, meaning the northern and southern brances of the jet stream essentially became one, allowing for the abundance of moisture and an intense storm.
Looking back to October 8-9 when the cycle was just forming, this part of the pattern did produce a storm, but only 0.21″ of precipitation occurred, comparing that to early December’s 0.84″, the result of each storm at the surface varied.
For this forecast I do think a storm will form over the Midwest in the Feb. 7-9 timeframe and likely bring snow to many areas. If enough warm air is pulled in, a mix or rain could occur. This will be one of potentially two major storms we see during February, and could be the biggest snow maker of the month for parts of our area. This potentially large storm could impact the region through the 10-11 as a quick shot of arctic air is drawn in on the backside of the storm. Again, it would be very tough for this storm to be as strong as the previous time through the cycle, but it will likely be somewhere between the October and December versions.
Let’s take a look back to the last time through the cycle, when this storm was a monster over the nation’s mid-section and then look ahead to February 8-9, which is next Monday-Tuesday.
Below is the 500mb map from December 9, 2009. I put a few numbers on this map for easy comparison to the map which will show this storm and how it is forecast to look early this week. Back in December the northern and southern branches of the jet stream phased…or became one. This allowed a lot of moisture to work into the storm, and translated into huge snow totals around South Central and parts of Southeast Wisconsin. Due to the warmer lake waters then, a good deal of rain fell near the shore in Milwaukee.
If you noticed the labels here is a brief breakdown. #1 the main upper level low, #2 the dominate ridge off the West Coast, and #3 another trough next to the ridge.
Now let’s jump ahead to early next week…around the 8-9 timeframe. Again, the pattern repeats with many features very close to the positions above. The map below is from the 12Z GFS for 6pm Monday. The strong upper low over the upper Midwest #1, the ridge now along the West Coast #2, and another trough behind the ridge #3. I also labeled an ‘X’ where another vort. max is located. If you remember back in December the southern and northern branches of the phased creating one large storm. This time through the cycle the piece of energy marked with the ‘X’ is going to play a huge roll in how this storm evolves. The map below shows a storm that is not phased, but close.
If the storm phases early enough, this would produce another significant storm for southern Wisconsin. I think the phasing may occur a little later in the storm evolution compared to December. But at the same time I do think snow is likely early next week. The question now is how much? At this point I will not put a number on the amount of snow, but will say I stand by my forecast and statements made in late January. This could be the biggest snow of February for parts of the area.
Below is a surface forecast map from our in-house high resolution computer model. This shows some light snow moving in on Monday. I marked the two surface areas of low pressure.
If you have been waiting for a good snow around Milwaukee, you may not have to wait too much longer. The 8-9 timeframe looks like our best chance at a decent snow! Make sure to check back this weekend for the latest updates on next week’s potential storm!