We are closing in on the end of cycle 2 and beginning of cycle 3. The pattern sets up in mid to late summer and becomes established by October. I don’t believe it is a coincidence that the sun sets at the north pole around the time the pattern is set. That occurrence seemingly triggers the event. In fact, in past years I did not start the first cycle on my prediction chart until October. Now I am able to find the pattern much earlier, thanks to a formula that interprets data from various teleconnections.
One of the cool tools that I am using is called the Pacific Oscillation (Index). I call it that because it indicates the size of ridges and troughs along the west coast. The Pacific Oscillation is similar to how the Arctic Oscillation measures the strength of pressure, positive or negative, at the north pole (to 20 degrees latitude). The strength of the PO, on a scale of +5 to -5 helps measure the strength of storms and prioritize them for upcoming cycles.
This years pattern has 3 main storms and 6 smaller systems that will provide average to above average to much of the west. The Pacific Northwest, again will be the winner with above average precipitation. I am predicting 125% of average or above. Colorado was below average, last year, for precipitation, generally around 80% of average, with a couple of isolated areas that finished near average or slightly above. With the pattern that I am seeing, it will be average to above. I am predicting 105-110% of average for the northern and central mountains with average to below average for the southern mountains. I will give this caveat, there has been a few cut-off lows in this years pattern that could provide a lot of moisture. As of now, I have not had much success in predicting cut-off lows until spring.
For the west and central mountains, there is a short inactive period around 10 days. This can change because there are small waves still passing by that can increase in size based on different teleconnection variables. These storms are called “wildcards” and do not repeat in the pattern. During this boring stretch the pattern takes a northern track blasting Washington, Montana, Wyoming and of course Canada. I will point out later, in a detailed post, when to visit resorts like Whistler, Banff, Jackson Hole and Big Sky.
The first big storm of the pattern has 3 waves of energy that I called the Trifecta in an earlier post. The first time this came through the pattern was still varying in length. Meaning the pattern speeds up and slows down until the length is set with twilight at the North Pole.
The Trifecta kicks off the active part of the pattern and has 2 large storms. There is a short stretch between this active part, about 6 days, then the pattern ramps back up again.
The huge Atmospheric River event in California will return. Then we conclude the cycle with a period that is hard to describe. There is rapid succession of ridges and troughs. The first two thirds of the pattern, the ridges and troughs are evenly spaced. The last third, the ridges and troughs get sped up, creating a roller coaster of sorts. That will be interesting to see if that continues in future cycles or levels off.
Thanks for spending a few moments reading the blog. As always, if you have any questions of thoughts feel free to make them in the comments section or email me at Mike@FutureSnow.co.