The push to colder weather and eventual winter comes in waves. In October, we ride these crests up before each chilly fall. The peaks decrease while the valleys become deeper, eventually by mid to late January, the peaks are at their lowest and we find ourselves in the depths of winter.

A review of the period from September 2014 to March 2015 really shows how this pattern plays out. Each year is different of course. The peaks might be further apart, not as steep or fewer and the valleys can become long drawn out flat bottoms like what we endured last February.

Take a look at the graph below from Portland. Notice there are consistent peaks throughout the fall, but the trend is always lower. Last year the typical rise didn’t begin until about 4 weeks after it often occurs. These charts are why I can often tell you when the coldest air mass of the season will happen.

This temperature graph reminds me of some of the tends of certain commodity stocks the past 6 months, they bounce off their lows, but the overall movement is downward, that’s another story for someone else’s blog.

Anyway, this pattern of upward and downward trends continues quite predictably each year. The brown line represents the “normal” or average temperature range from 1981 through 2010. If you looked at the normal range since the 1800s, you would see the trend has been higher.

The cold winter really shows up nicely on the chart. Not only were we far below any record high temperatures from late January through early March, we were well below the average or normal range. Since I love charts, tables and numbers in general, I find these types of charts quite interesting.

Warm Columbus Day
We are about to go into a colder period of weather late this week, but not before a very mild Columbus Day. A flow of warm air is surging north on a southerly flow. Temperatures to our south and west have been running hot for days. A small, brief piece of this air will arrive tomorrow and with temperatures in the 60s today, it may feel like it’s here already. For the holiday, mid-70s will be common and the warm weather will continue into Tuesday.

A cold front pushes the summer-like readings east Tuesday and returns the mercury to seasonal norms. We might see a shower or two as the front passes, but nothing serious and many of us won’t see a thing.

Cold Snap
There’s a point in October where I must turn the heat on. This point hasn’t arrived yet, but it’s coming. I figure sometime beginning Friday and continuing through next weekend it will be so chilly the house’s internal temperatures will fall below 60 degrees. This usually happens when the days stay in the lower 50s and the nights get into the lower 30s and that’s precisely where we appear to be headed late this week.

The chill will last about 3-4 days and likely peak or bottom Sunday or Monday morning, and then a new warming trend will begin, but likely not reaching the levels we will experience Columbus Day. I feel a palatable comfort in knowing there’s a cyclically predictable pattern to all of this even if I’m not looking forward it.

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