Cycle 4

The 4th cycle is under way. At the beginning of each cycle the storms favor the Pacific Northwest and Canada. This has occurred in each of the previous three cycles and GFS verifies same for the beginning of this cycle. The cycle is 45 1/2 to 45.8 days in length. I have adjusted the upcoming predictions by a couple of days to correct this offset.

When talking about the cycle, every year is different. Last year had a longer cycle, La Nina favors shorter cycles. Presently this La Niña is weakening, the Arctic Oscillation is neutral, the north Atlantic Oscillation is neutral, and the Madden Julian Oscillation is in phase 7 in the western pacific. All of these tele-connections influence the strength and path of storms. However, the framework, or structure of the storm path, remains the same throughout the spring and it weakens in the summer until it is wiped out in late summer.

February 27th Colorado Prediction

This forecasted storm was made on January 26th as I dove back into the history of the previous cycles. I missed this “pattern storm” and discovered it through a little forensic analysis.

History of the storm

Day 6 of last cycle, a small wave hit Colorado, followed by a large wave impacting the PNW. In cycle 2, again a small wave hit Colorado followed by a small wave hitting the PNW. In cycle 1 on day 7 a small wave hit CO followed by a large wave in the PNW. So when I decided to add this to the prediction grid I decided to add it on day 7, probably not a smart choice because it hit on day 6 twice but my thinking was it hit late on 6 both times and the day 7 storm it was during the day.
The GFS has this storm arriving at about 6 am on Thursday the 25th. This is actually right on time—if I would have been “on it” and adjusted the cycle length to reflect the uneven cycle (45 1/2-45.8 days).

FutureSnow CO Prediction

I have adjusted all future predictions by 2 days to correct the cycle to match the storm cycles. I am not going to update the existing storm forecast for February but the March schedule has been adjusted. Below us the updated predictions spreadsheet.

This Weeks Picture Challenge

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