Monday, October 29, 2012

What The LRC Is Saying About This Winter

The above image is of observed precipitation and storm tracks, with the strength of those storms on the bottom of the image. All you might see is lines and colors. But this actually holds the key to deciphering the LRC, or Lezak Recurring Cycle.

But before we sort this all out, what is the LRC?

The Lezak Recurring Cycle is:
•A weather pattern that sets up every year.
•This pattern is NEVER THE SAME from year to year.
•Pattern sets up in late fall-early winter.
•The LRC cycles (repeats) through the winter and spring from the original pattern in the fall.
•Each cycle is 40-60 days.

For example, if a system were to go through the Midwest in mid October and brought a lot of rain to the region, you might see the storm again in December (40-60 days later) in the Midwest again with a lot of precipitation. However, strength and track varies with each cycle.

Looking at the graphic above, we see a lot of lines going through the Plains and Midwest. This correlates well with the precipitation being centered in the southern Plains and Midwest. If we put the LRC to use in this 30 day observation, one would think that the Midwest and Plains will bear the brunt of storms this winter.

And here's the thing- I believe it.

A consistent positive Pacific-North American (PNA) phase makes for a wet and stormy Midwest and Northeast. The PNA was observed to be variable in the last month, but a consistent negative North American Oscillation (NAO) changed the jet stream to give a lot of cold to the East US. If we put these two together, we get a wet, cold East US.

Things are still developing, but this is a great sign for those wishing for a snowy winter in the Midwest and Plains.



Cameron Fry said...

Hopin' this benefits KY & TN as well...

Anonymous said...

First, Andrew I'm new to your sight having discovered it a couple of months ago. Thank you for everything that is on it. Weather is a hobby for me. I currently reside in the Southwest, New Mexico to be precise. I keep hoping the pattern changes to bringing some kinda precip to us. The last few years with the La Nina and weak monsoon seasons it has been a little boring. But, despite the La Nina's of the last 2 winters there have been some interesting weather events locally. So I would expect the same this year and enjoy whatever snow may fall because it is hit or miss mostly.

Owen12789 said...

When you say midwest, can you please pinpoint where? I live in Springfield, IL and I am curious to see where the snow is forcasted to fall. I am getting married in December and we are hoping it snows a little bit!


Anonymous said...

So if I am understanding you correctly Andrew you in one sentence believe the Plains and Mid-West bear the brunt of winter but then in the last paragraph state that the east is cold and wet. I am confused, are you implying that the midwest gets all the snow the east gets mostly rain???

KakHome said...

Same concern as Anonymous posted at 2:55 PM Oct 29. I live in Cleveland OH. Does this cold/snowy forecast include me and do you expect it to be at least normally cold even in the east?

Anonymous said...

More bad news for a dying Colorado

Andrew said...

Cameron: It could, and probably will if the -NAO regime continues.

Anonymous: Great to see you! I would not be surprised to see a cutoff low bring some good precipitation to the area. If the subtropical jet stream happens to get active, then the Southwest could get much wetter.

Owen12789: 'Midwest' as in IL/WI/IA/MO/IN, so yes, Springfield would be included. Congrats on the wedding, hope you get some snow!

Anonymous: The last paragraph describes what two indices do on average, while the sentence defines what I have observed. So the sentence is the forecast, the paragraph is what happens when the NAO/PNA combine.

KakHome: It will very likely impact Ohio- the state has been wet for the month, and this is part of the LRC.

Anonymous: It can all change with one big storm- don't give up hope!

mike paulocsak said...

Hello Andrew.I have been getting rain non-stop since yesterday morning.I would say i'm closing in on 2 inches.The rain is basically stationary,it's not going anywhere fast.If this wet pattern continues through the winter months,Ohio eastward is going to be hit pretty hard.It is wetter than last year at this same time.And last year was extremely wet around northern and eastern Ohio.

Anonymous said...

Thank you for all your hard work Andrew, I have more respect for you than any other forecaster I have seen because you try to capture every last aspect of the weather, not just bits and pieces that are manipulated to favor a certain area, my concern for Colorado is, one single storm, no matter how powerful it is, will not be enough to help our drought situation, it would take multiple MJO pulses slamming us as hard as possible to even put a dent in it, even recently we have had wildfires in our state, even as the temperatures drop, and it scares me, because it just doesn't happen this time of year, but it is.
Where I live, we are around a foot below normal precip being that summer was unbelievably hot and dry, we set new all-time records for heat because of persistent blocking highs that refused to move, and now things are looking hopeless to an extent that I have never seen in the 20+ years that I have lived in this state, being that there is little chance that even normal snowfall will occur this winter, as most models are calling for below normal snowfall and well below normal precip for the central mountains and especially the front range, it really worries me, we need it so badly, like Texas needed it in 2010-2011, the difference is, Texas is in a location near a major body of water, Colorado is not, so it virtually takes an act of God to get a good storm over the front range, and even then, they are rarely very widespread, only terrain-driven, and even to get a terrain-driven storm anymore, the storm has to track right over the top of us, otherwise we get nothing, it isn't like it is out east, where no matter where the storm tracks, everyone gets something.
Anyways, sorry for the long post, I am just wishing there was hope like what you were saying, but I am afraid that we need alot more than hope to ever recover from this monumental disaster.

KakHome said...

Do you expect near, below, or above normal temps/snow for the I95 area, and if not near normal what anomalies?

Thanks for covering OH in the meantime. :)

Anonymous said...

What about Kansas?