Long Range February 2011 Forecast

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Thank you for stopping by the Weather Watch 12 blog!  In today’s entry we will look at the long range forecast for February based on the LRC.

If you are new to the blog or just need a quick refresher.

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.

As I have mentioned many times, this year’s cycle duration is about 46-52 days.  Overall most of the weather events have repeated about 47-50 days apart.  After analyzing the pattern and surface results from October through early January, I was able to get a very good idea of what should occur this February.

Here is a week by week breakdown of the month ahead.

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February 1-7

The first week of February should be accompanied by below average temperatures.  As I stated back in mid-December, I still expect the coldest temperatures for Milwaukee to occur in this timeframe.  Back in early November and again in December, about 7 days after our ‘signature’ storm, a trough dug into the Great Lakes.

Below is the 500mb map from November 4.  As the pattern repeates, this large trough dropping into one of the main long term longwaves should push very cold air into the Great Lakes.  Keep in mind back on November 4 there was no snow on the ground, and the arctic air was not residing to our north.   

Large Trough Over Great Lakes On November 4, 2010

While the first week of February looks cold, the chances for snow appear to remain on the light side.  A wetter storm could move through parts of the South and up the East Coast as the trough digs into the Great Lakes.

February 8-14

After a cold start to the month, temperatures should moderate early in this period.  Snow chances would likely be provided by ‘Clipper’ systems.  This period will be the transition from the cold start to the month, to a milder stretch of weather with the potential for above average temperatures.

During this period a trough will dig into the West, and this will begin to lead us into potentially the strongest storm of the month. 

February 15-21

From around February 14-18 I expect the most active storm system of the month to impact the region.  As a large trough digs into the West, milder weather should arrive across the Midwest.  The previous two times through the pattern temperatures have been well above average. 

I expect another mild stretch of weather, with chances for precipitation on multiple days.  As the main storm lifts into the Midwest, the track will be key.  Both times through the cycle the heavy precipitation has missed our area, with the main upper low staying over Minnesota.

Below is the 500mb map from November 14, the first time the storm appeared in the cycle. 

Trough Over Midwest On November 14, 2010

The second time through the cycle the storm brought fog, drizzle, light rain, and very mild temperatures to our area from December 29-31.  Below is the 500mb map from January 1, 2011 as the main storm ejected into the upper Midwest.

Large Trough January 1, 2011

This storm will need to be watched as it could bring all types of precipitation to our area.  I do expect temperatures in this period to be above average, possibly the warmest day of the month occurring here.  Temperatures will then drop off and may be colder than average for a day or two behind the system.

February 22-28

Early in the last week of February a clipper system or two should pass by with chances for lighter precipitation, and also a shot of colder air.

The highlight of this week should be the final day or two of the month.  Both in November and January a storm system produced around or more than 0.20″ of precipitation.  In November it was nearly an inch of rain, while in January it was 2.7″ of snow.  This system should once again move into our area as the flow turns more southwest to close the month.  The month should also end with temperatures around average. 

——————————————————————————————————-

Now that I have provided my thoughts for each week of February, let’s take a look at the overall forecast for the month here in southeastern Wisconsin.

February Forecast

  • Temperatures: Below Average
  • Precipitation: Below Average (Likely Average to Below Average Snowfall)

If you are curious, the average precipitation in Milwaukee for February is 1.65″, while the average snowfall is 11.3″. 

Those are my thoughts based on the LRC and the overall weather pattern.  Let’s compare this to the Climate Prediction Center’s February forecast.

Below is the CPC’s precipitation forecast, which calls for increased chances for above average precipitation in southeastern Wisconsin. 

Climate Prediction Center's February Precipitation Outlook

When it comes to temperatures the forecast based on the LRC, and the CPC’s are both calling for below average temperatures.

I am confident of the February forecast that I posted above.  But I just want to remind everyone that the forecast is made using the position of long term longwave ridges and troughs, the cycling weather pattern, and past surface analysis.  Just one mesoscale event like a prolonged lake effect snow could mess up one aspeact of the forecast.  That is why I try to provide my thought process and break the forecast down into weeks. 

Thank you for reading and please post any questions or thoughts that you may have on the February forecast or the LRC. 

Have a great day!

Jeremy Nelson

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10 Responses

  1. All I know is that every time your LRC forecast doesn’t match up with the CPC’s, the latter is always wrong. I have to wonder what data they use to get their results because it doesn’t seem to be too reliable.

    All these other sources seem to latch onto the typical La Nina pattern and so far this season, it has been far from normal.

    Typical La Nina pattern for this region… vast temperature swings and big storms tracking through.

    This season’s pattern… barely any temperature swings (very few bitter cold days, very few mild days) and no big storms as of the midpoint of winter.

    • Daniel,

      I always try to use the LRC, but then look at other influences such as La Nina, El Nino, PNA, AO, etc. Basing a forecast off just La Nina alone is risky in my opinion. Look at the temperature forecast from last summer that the CPC made, that ended up being pretty far off.

      The LRC forecasts are not perfect, but I will stick with this theory for long range forecasts.

      Jeremy

  2. Hi Jeremy,

    Just dropping a quick post to let you know I’m still following along with the blog. I’ve only been following it on a regular basis since around Thanksgiving or thereabouts. It’s managed to work it’s way onto my must check at least once a day list and preferably more often. I find it all quite interesting, especially the LRC discussions and comments.
    Hope to make contributions of observations, measurements, and perhaps a photo or two whenever it seems they are welcome.

    Cordially,
    Tony

    • Tony,

      It’s great that you are a part of the blog! Feel free to post your weather reports here anytime. Also, if you get pictures you can post them to the U-Local section, but also send them via email to us too! Thanks for reading.

      Jeremy

  3. Jeremy —

    If I’m reading correctly, the Feb. 14-21 period has the potential, at least, to be the “stormiest” — but if all variables stay the same as it looks now, the “storm” that week would bring warmer temps, which would most likely translate into rain or sleet, but likely not snow, or at least not much snow. Am I on the same page with you about this?

    Also, if I understannd correctly, we shouldn’t expect any “big” snows in Feb. — at least as of this point? Of course if the “signature storm” isn’t willing to come our way with a big snow, why should we expect lesser storms to bring big snows — 🙂

    Just wanting to be sure I’m understanding all of this correctly.

    Thanks for any help you can offer me!

    Don in Reeseville

    • Don,

      I would say week 3 has the potential to be the ‘stormiest’. This would be the repeat of late December heading into New Year’s. That brought very mild weather, and then a quick drop in temps. There was plenty of moisture with that system, but it missed our area, we had something like 0.05″ of precip. We’ll have to watch the exact track closely.

      I think the probability of a ‘big’ storm in the first half of the month is low, there may be a little higher chance in the second half of the month. Keep in mind ‘big’ could be rain or snow. Still I think below average temps and precip. look good.

      Jeremy

  4. Jeremy- What is your take on what the GEM and ECMWF are showing for early next week? I see the GFS doesn’t want to latch onto it yet. I know how a cold H can really keep things south.

    Thanks in advance!
    Ron

    • Ron,

      The GFS has done poorly as a whole this winter, but better as of late. I have noticed the ‘storm’ on some models for early next week. The new blog I’m working on now touches on early next week. I’m not excited yet, but watching closely. January 31-February 1 certainly fits better with the ‘signature’ storm of December, based on 50 days. But the strong jet streak that is in place near the Pacific Northwest now would lead me to think this Saturday is the ‘signature’ storm. It wouldn’t be the first time I misread the pattern:) But right now I’m still thinking the wave this weekend is the ‘signature’ storm’s wave moving by.

      As of now I’m not making any big changes to my thoughts, but will keep an eye on how the models trend.

      Jeremy

      • 😉 Good answer. It will soon become obvious. I got my money on the Euro.

  5. One thing that might suggest early next week is the signature storm is how bad the models are handling that system. They sure had variable solutions the last time around. With the arctic air delayed (at least on some sources) until later next week too, that could be another sign.

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