February Forecast

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

Thank you for stopping by the Weather Watch 12 blog. In today’s blog we will take a look back to the January forecast that was made on December 29, and then we will go over what to expect for the entire month of February in Milwaukee. Will winter storms hit the area, how cold will it be, and is Spring near? All of those questions will be answered in the complete February forecast!

Making long range forecasts is always tricky, but a weather pattern theory known as the LRC allows for accurate long range weather forecasts to be made. LRC stands for Lezak’s Recurring Cycle.

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.

Back on December 29 I used the LRC to make a forecast for the entire month of January. Over 3 weeks out, the storm that occurred this past weekend was forecasted, along with it also producing our warmest temperatures of the month. The arctic air that is heading our way for Thursday/Friday was also highlighted in this forecast! Below is the forecast for the last 2 weeks of January from that December 29 blog entry.

January 16-23

This week of January picks up with the storm described above. Back in November the storm impacted the area from the 15th to the 19th. We could see snow showers early in the week with cold temperatures, and then a warm-up around the 20-23. The warm-up around the 20-23 into the early part of the following week could bring us our warmest high temperatures of the month, possibly a January thaw. By the end of this week the focus will shift to a potential storm.

January 24-31

The last week of January looks to be the most exciting and wettest of the month for our area. Let’s start by looking back to November and our wettest storm of that month. This is a 500mb map from November 24.

If we are going to see a major winter storm during January, I think this would be the storm and timeframe for our area. Again, the question will be where does it move, but unlike the storm around the middle of the month, this one should lift north into our region. This storm could be rain, sleet, snow, or all of the above. This storm should be followed by a push of arctic air that likely will end the month cold.

 

The book is now closed on January, what can we expect for the month of February? This foreast will be broken down into 4 periods with map comparisons to highlight the focal points of the month. After a somewhat quiet month of January with really only 2 storms systems, February should be much more active for Southeast Wisconsin, and also a little colder.

February 1-7

The weather pattern during the month of February should be a lot like the one that occurred this past December. Back on December 3, an Alberta Clipper raced across the northern U.S., and in its wake pushed colder air into the region. This is exactly how the 500mb(roughly the middle of the atmosphere) chart looked that day. A large trough was located over the Midwest, with a ridge pushing up the West Coast.

Comparing that map to what’s ahead for the first couple days of February shows the weather pattern continues to cycle! The map below is a forecast map from the 6Z GFS. It shows the trough over the Midwest and also a ridge pushing up the West Coast.

So for the first week of February, we can expect a clipper system right around Groundhog Day. This should provide the area with some light snow, snow showers, or flurries. The Groundhog, at least in Southeast Wisconsin should not see his shadow. This should not be a major storm, but could produce a very light accumulation of snow. Behind that clipper there will be a shot of cold air, but it should not last too long. Temperatures the first week will be average to slightly below average as a whole.

Late in this period a trough should be near the West Coast, and one that will likely impact our weather!

February 8-14

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.

This is how the storm looked at 500mb on the morning of December 9. An upper low was over northern Illinois, and colder air was beginning to wrap into the storm.

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.

By late in this period another clipper system will move through the region producing snow showers. Ahead of this clipper temperatures will likely jump to around average…in the 30s. Behind the clipper another push of cold air will drop temperatures.

February 15-21

This period of February will likely bring active weather to parts of the South, East, and Northeast. We’ll watch for a big storm to form and move from the Gulf Coast to the East in the 17-19 timeframe.

Tempeatures should moderate during this period, and by the end, our focus will shift to a storm in the West. There could be light snow by the 21st around Wisconsin.

February 22-28

The last week of February should bring a couple of things to Milwaukee…the wettest storm of the month…and also the warmest high temperature of the month. Let’s compare this back to December first.

The map below is from December 24, two well defined upper lows were stretched across the Plains. This would eventually form into a very impressive storm that brought over 1.50″ of precipitation to Milwaukee…most of that falling as rain. Looking back 60-62 days from December 24 to October…keeping in mind the 60-62 day cycle…another very wet storm produced over 2.20″ of rain in Milwaukee.

This was a long duration storm for our area that came at us in a few pieces, with the main energy around December 24-25. I do expect this to be a wet storm once again, with the greatest impact from February 23-25, but even around the 21-22 some snow or a mix could occur. This storm should once again bring rain to the region, with some mix/snow. This would be the second of 2 big storms for Milwaukee in the month. During this period we will also see our warmest temperatures of the month…likely occurring around 23-25.

Behind this storm the month should end cool.

Overall for the month: I expect temperatures to be near average, and precipitation to be above average. Snowfall should also be close to average…11.3″

Those are my thoughts and the reasoning behind this February forecast. Again, this is a theory that I believe in. Mark, Sally, and Lyra are still watching and learning about the LRC. I encourage anyone that has never seen or heard about the LRC to follow along in the blog and ask questions over the next 6-12 months. I am still amazed each time I see the pattern cycle!

Feel free to leave your thoughts and questions in the comments section of the blog. I will do my best to answer any questions that you may have.

Have a great day!

Jeremy Nelson

Advertisements

5 Responses

  1. How long did it take you to do this entry?? WOW

    • I think an hour and a half, but made the forecast this past Saturday. Most of the work was done before I typed it up today. It should be fun to watch Feb. play out since the pattern is known.
      Jeremy

  2. Not to contradict all of this as it seems to have nailed the recent storm very accurately, but wouldn’t the cycle be different this time around because of the rare Greenland high pressure block that existed for weeks back in late Dec, early Jan. This setup is what caused the track of the Christmas storm to turn out the way it did. I think all of the forecasts about a week in advance said that storm system was going to go through the deep south and turn up the east coast for a major snowstorm but the Greenland block wasn’t breaking down and forced the storm straight north from the Texas area and eventually to the west of us. So, could this late Feb storm follow the path it would have naturally followed without the block and actually hit the south and east and miss us completely instead?

    • Daniel,

      Thanks for the question. The number of days in the cycle will not change in my opinion. However each time through the cycle the results are not exactly the same, but more times than not they will be close. The storm you are referring to in December was a repeat of the October storm. Look back to around Oct. 22-25 when over 2″ of rain fell, then 60-62 days later another very wet storm hit the area. So I am confident the storm will also be pretty wet when it heads back our way the last week of February.

      The LRC focuses on the long term long wave trough and ridges. The dominate long term long wave trough this winter runs through the Plains. The last two years this trough was near or east of the Mississippi River. Look what happened in Milwaukee those winters…it snowed…and a lot. So with the main trough staying to our west this year, it is allowing storms to lift or eject far enough to our west, that mild air is giving us rain with many of the storms. I don’t see this changing, but there will still be a couple of decent snow chances this month. Keep in mind the average snowfall for February is around 11.7″, and I think we should be around that this month, but above average for precipitation.

      Jeremy

  3. Daniel,

    I think you bring up a great question. The Greenland block is indeed more unusual with the strength and longivity it had through December. That said, in thinking about the LRC, I think of it as a series of waves in the wavetrain of the Westerlies. I think these cycle on a regular basis, but your point is valid to the extent the surrounding synoptic setups can/do have an effect of storm paths. So, while the storms are cycling, with seasonal variability as well as how other features set up could have an impact. But – that said, let me think aloud about your point regarding the blocking.

    As the pattern is cycling, and as the LRC is also defined in long term longwaves, then by definition there should be some repeating of the associated features such as the blocking you discuss. I can think of showing this in two ways. The first is in just looking at the blocking itself. Here is an image saved about a month ago showing the blocking back through October into the middle of December.

    http://tinyurl.com/yh4aza5

    As illustrated, while the intensity increased with the seasonal variability of Winter compared to Fall, the pattern distribution was similar. Also, in thinking of synoptic patterns, I think of the teleconnections as a numerical way to measure pattern types. Specifically in this thinking, I am looking at the Arctic Oscillation. As unusual as the Greenland high was in this case [last time I can think of similar of similar strength and duration was January 1977], as being related and measured by that anomaly was the record low index of the AO for December.

    Was the AO trend in December unexpected? For many – yes. It overtook the normal El Nino signal and exerted its own dominance over the northern Hemisphere. If you think in the terms of a repeating pattern like the LRC, it should not have been a surprise. If you look back at the trend of the AO and think about a 58-64 day cycle, then indeed a clue would have been what occured in October. In its own right, October was also quite the month. It also was cold for most of the US and it too had low AO values. In fact, if my research is accurate, it’s monthly mean was the lowest October value since 1950. This should have been a trigger/clue for what might be upcoming. Look at the trend.

    Note the downward trend in early October to its peak to have a rise and to fall again while the entire month stayed negative. Look at December. Same downward trend into the second week to have a rise and to fall again. Both months then begin a upward trend and stay near that mean until the next cycle where it falls.

    Looking ahead, the AO is progged to tank again into February. Does the AO or any of the teleconnections clearly resemble the LRC? Not always. Because there are other factors beyond a few measuring points needed for each teleconnection measurement, there may be other factors such as the ENSO or MJO that could have an influence. But it is just that, an influence. The cycle remains, but it is important to think of these other factors/relationships in conjunction with the LRC for the most accurate long range forecasts.

    So, while the Greenland Block did have some influence, there is enough other ways to evaluate the pattern to expect a similar type pattern to return. While intensities may vary and storm tracks may be impacted based on that, all in all, it should largely resemble the same storms and tracks.

    Just my opinion…

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: