WINTER FORECAST 2008-2009 (issued November 24, 2008)
A unique weather pattern has set up across North America and the entire Northern Hemisphere. This forecast is based on my theory, the LRC. The theory has the following main components:
- 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 is critical to making accurate predictions on when storm systems are likely to hit a local area
- “Long term” long-wave troughs and ridges become established and also repeat at regular times within the cycle. These dominant features can be used to identify where storm systems will strengthen and weaken most often throughout the year
- 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
Here are the main features that will likely affect the weather pattern this winter:
Dominant feature #1:
One of the stronger features is a long wave trough that extends from Hudson Bay south through the Great Lakes (eastern Michigan) down into the Alabama/Georgia line. This is a major feature in the cycling pattern, as it will likely be carved out three to four times during each cycle. Even the western and central storm systems ended up phasing into this Great Lakes trough.
Weaker feature #2:
There is another long wave trough that deepens through the western states that likely exists near the Texas/New Mexico border extending north through the western plains. This feature is not as powerful as the eastern trough, but it is there and likely will be carved out four times during each cycle.
Feature #3:
There is a mean “long term” long-wave ridge over western Canada north of Washington and Idaho extending into northwest Canada and this is a strong feature in this years pattern. There is a “long term” long-wave ridge near Southern California that tends to drift off shore quite often and will likely link up with the Canada ridge at times this winter.
Feature #4:
Split flow has developed many times during the first cycle in October into November. This will likely continue to be a major part of this winters weather pattern.
Let’s go through each of the above features:
The Great Lakes trough (Feature #1):
Energy has been generated just east and south of the western Canadian mean ridge caused by temperature contrasts that are now growing in strength in that region. One of these developed late in October near the US/Canada border as you can see below, and then the jet stream energy dives southeast across the Rockies through the plains and a trough is eventually carved out into the mean position creating the set-up for a major storm system at the surface. This also happened between October 16 and 20, and between September 27-Oct 4, just as the new long waves were becoming established. Go to www.LRCWeather.com for how this long wave feature develops. Here is a look at the Great Lakes trough:
The western plains long-wave trough:
Energy diving southeast into the western states has formed into long-wave troughs on a few different occasions and this will likely be a big factor at times this winter. The troughs happened in the critical developing period of the LRC: October 8-14, October 20-25, Nov 3-7, and November 9-13.
This long-wave trough will likely repeat within each cycle. The trough may form from various initial conditions, but eventually end up in the long wave position. What I mean is that the energy could come underneath a split, or south around an eastern Pacific upper high, but in either case the end result will be in carving out a stronger plains trough that drives through the western states. You can see how this developed in October:
Jet energy develops near the west coast. This is how it formed in October, and computer models will have a very hard time picking this feature out until it is three to four days out from forming:
The energy then digs, strengthens and starts carving out a western into central United States trough:
On the left front quadrant of the jet stream an upper low formed in October, and will likely happen again two or three times this winter:
The mature trough has now formed a powerful upper level low that will likely produce major winter storms:
"Long term" long-wave ridge (feature #3)
During the cold season the Canada ridge will tend to retrogress to off near the west coast of Canada and extending to off the California coast. It will likely try to close off upper level highs this winter a few times. When this happens we will likely see brutally cold Arctic air masses develop over central and western Canada. This will likely block up the flow over North America and lead to long stretches of cold weather across the United States. During predictable parts of the pattern this ridge will likely develop and help create some stormy set-ups across the United States.
As we move later into spring the ridge will tend to form over this years more favored long wave position north of Montana and likely lead to cut-off lows in the south central and southwest parts of the nation in developing split flow. Look for this to happen as we move into the spring months.
An example of split flow and the likely combinations of features 1, 2, and 3 above is shown on this next map. The mean ridge can be seen off the west coast and strongly into southwest Canada:
As all of this comes together we will see some rather wild temperature swings and storm systems moving across the United States.
2008-2009 Temperature Forecast December through March:
2008-2009 precipitation forecast December through March:
There will be dry and wet parts of this years weather pattern. More on what we see in this years cycle below, but first here is the more specific forecast for the Kansas City area.
KANSAS CITY AREA
- Near to below average temperatures
- One ice storm most likely south of Kansas City
- Two or three major Arctic outbreaks
- 20 to 25 inches of snow
Snowfall prediction probability chart (December 1st to April 15th):
- Chance of 4" to 10": 5%
- Chance of 11" to 15": 10%
- Chance of 16" to 19": 15%
- Chance of 20" to 25": 50%
- Chance of 26" to 29": 15%
- Chance of 30" or more: 5%
We are narrowing in on the cycle length in this years LRC. It appears to be close to 51 days, give or take a few days. As soon as we are more confident in the cycle length we will make specific forecasts picking out dates in the longer range and issuing these forecast on NBC Action News and in the blog. Meteorologist Brett Anthony will add his thougths on NBC Action News in the morning. Jeremy Nelson will come in with his ideas later in the week. Here is the link to our winter forecast we showed last night, and our disccussion more in-depth:
http://www.nbcactionnews.com/mediacenter/local.aspx?videoid=423140@kshb.dayport.com&navCatId=3721
Have a fantastic day. We will try to answer your questions and comments.
Gary Lezak