Thursday, January 8, 2009

LRC and Gary Lezak's long range forecast

The “long term” long wave troughs and ridges set up across the northern hemisphere by early to mid October. And, now we are experiencing this year’s LRC in Spokane, Wa where they are setting snowfall records this winter. This years LRC is exciting for the weather enthusiasts across the Dakota’s through Minnesota, Wisconsin, Michigan, and northern Illinois where Arctic air blasted in with many storm systems. Snow has fallen in locations that rarely see any snow at all like Las Vegas, Houston, and New Orleans. Other areas have been missed by the weather excitement. Even in our viewing area we are still waiting for our first major winter storm of the season. Rich Hill, MO and across the border to Pleasanton, KS have had less than an inch of snow this entire season thus far. All of this is directly related to the LRC which is the weather pattern that evolved in the fall and is cycling now.

The 2008-2009 LRC Cycle:

The “long term” long waves are of extreme importance when using the LRC to make seasonal forecasts. But, it is the cycle and knowledge of how the weather pattern is cycling in and out of its various phases that allows us to make much more specific forecasts. This year we have found the cycle length to be approximately 50 days give or take a few days. Last year the cycle length was closer to 52 days. In 2007-2008 the cycle length was around 45 days. Remember “the storm” that seemed to happen right on schedule every 45 days that year, and predicted by us weeks ahead of any computer model! So, each season has a different cycle length. We still haven’t found the cause of the cycle or the LRC, but we are doing ongoing research in this area.

To make this forecast we are using an average of around 50 days for the cycle length. If the cycle length is just two days longer or shorter at around 52 or 48 days then the dates below could be off by 5 to 10 days as we go into the next few cycles. Assuming the pattern began around October 2nd, 2008 and using the average 50 day length we can define each cycle below:

First cycle: October 2-November 21
Cycle #2: November 21- January 10
Cycle #3: January 10-March 1
Cycle #4: March 1-April 19
Cycle #5: April 19-June 8
Cycle #6: June 8-July 28

We believe the LRC weakens and falls apart back into more of a chaotic pattern late in the summer and gradually evolves and morphs into a new weather pattern each September and into October. We are also convinced the pattern never stops cycling with the cycle length going through a transition by mid-summer. This is something we are just noticing in the past two years.

The LRC Long Range Weather Forecast
Issued January 7, 2009

There are phases within the entire 50 day cycle that occur at regularly scheduled times. There has been a dominant eastern midwest into a Great Lakes trough, this is one of the phases the repeats quite often. There is also a phase that allows for a retrogression of the troughiness into the western United states, but even when these western storms did form they would still regenerate and intensify as they approach the more dominant trough. Kansas City has just been in the wrong spot for any major winter storms. We have yet to see even one upper low track south of our area. It is difficult to have a major winter storm in your area without an upper low tracking south of you. It can happen, but it isn't as likely. These conditions are continuing, but we will get a late winter twist to the pattern and it may produce that one or two bigger storm systems.

January 10-18th: North flow aloft from Canada develops, but should break down by the end of this period. Some rather strong blasts from the Arctic will fully affect the northern plains and the Great Lakes states. Kansas City will get two or three cold blasts from the Arctic build up that is just waiting to attack us. There may be some minor precipitation events with some small snow accumulations across the viewing area with disturbances coming in from the north and northwest.

The two maps below are quite fascinating. This first map was shown during our winter forecast on NBC Action News (November 24th). We were concerned that this trough would place us in an unfavorable spot for major winter storm systems. The second map below is the actual forecast for next week. This has happened many times in varying strengths during the season.

The map, below, is the GFS forecast for Tuesday, January 13th:

January 19th-23rd: A stronger storm system will likely form near the central plains states during this period, but it strengthened just east of us the last time through the cycle and I am concerned that this is another storm that will not quite get its act together here. Another strong cold front will move through but a warm up is likely in the transition that is about to happen into the next phase of the 50 day cycle.

January 24th-31st: We are expecting a drier period again across the central plains with Arctic air reloading across Alaska and Canada, likely stronger than at any other time this season. This will be setting the stage for a huge Arctic outbreak and the initiation of the active part of the pattern for our part of the nation.

The map below is the actual 500 mb chart from December 14, 2008. This part of the pattern will likely return around February 2-5th, and then again around the last week of March. This part of the pattern was the wildest and stormiest across the United States.

February 1st-15th: The active and stormy phase of the pattern will return with many opportunities for heavier precipitation. The two week stretch of December 11th to December 25th produced some rather exciting weather set-ups across the United States, but Kansas City did not experience a major winter storm. We are expecting one or two major winter storm systems this time across the Kansas City viewing area with the February twist. If we are going to see a major snowstorm it will happen in February this year.

February 16th- 28th: Arctic air still invades the United States with some huge temperature swings continuing. The active part of the pattern should end in the middle of the nation as we move through this stretch of days, but there still may be one more storm before it calms down and warms up by the end of the month.

March-April: As spring approaches the weather pattern will likely begin producing some very different results at the surface. The jet stream will be retreating and weakening very slowly during March. The active phase of the cycle will return during the last week the month of March and we are still analyzing how this LRC will behave at this time. Will the winter blasts return or will spring win out. April will likely begin wet and stormy, but the quieter part of the pattern returns for the second half of this fourth month of 2009.

Forecast for Kansas City:

Near to below average temperatures will continue
January will have below average precipitation
February will have above average precipitation
KCI will end up with around our winter forecast of 20-25 inches

Visit and for more on this forecast, and the LRC.

Alex Pickman


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