This winter and the past five What should we expect?

Looking over weather data from my personal weather station of the past five winters, December, January and February, were interesting, though no trends are revealed. A half decade of data does not create a trend. It's just not enough data to crunch and draw some conclusions. I mention this because it's arbitrary to make a statement about climate solely based on short-term weather observations. I've included a chart with data for low temperature and snowfall for the past five years. As you can see, it's all over the place.

A 30-year average is the recognized standard. This is what the scientists with the National Oceanic and Atmospheric Administration (NOAA) state. "Every 30 years, climate scientists calculate new averages. The normal high and low temperatures reported on your local weather forecast come from these 30-year averages."

We do have enough data from our official weather station to draw a few conclusions. Here's another chart of mean data for our winter months showing low temperature and snowfall.

In the past few columns, I've stated that we are still in a La Niña year. Generally, our winters are cooler and wetter during a La Niña. It will likely affect the outcome of Winter 2022-23 when it's compared to the 30-year average.

I attended a weather webinar about a month ago. The speakers were from various public and private sectors. Most are professional meteorologists. The part I was most interested in was discussion of what may occur nationally this winter. Let me share a snapshot of what was said.

The discussion took a step into the past, looking at minimum winter temperatures. The southeast and east have a slightly warmer overnight winter minimum temperature compared to 50 or 60 years ago. On the other hand, the central and northern plains are slightly cooler. Here in the west, temperatures are a bit warmer. Acknowledged was the long-term drying trend occurring in Texas, the Southwest and California when compared to the past 40 or 50 years.

Next, there was a short discussion about when is the coldest part of the winter. It was explained that in the West and Pacific Northwest, generally it is late December to early January. It varies throughout the rest of the nation.

Next up was a look at the factors that are used when predicting winter conditions. First to be mentioned was the El Niño Southern Oscillation (ENSO). This is the dynamic fluctuation of water temperatures in the Tropical Pacific Ocean. Dependent on those temperatures, warm or cool, it is referred to as El Niño or La Niña. By far, the ENSO has the greatest effect on winter weather. Decadal trends are looked at too. That is the shifting of temperatures over the past decade. Also used are advanced climate models along with other elements.

La Niña is expected to neutralize in late January 2023. By spring it's felt La Niña will have dissipated. In our current La Niña situation, they stated we should expect heavier-than-normal precipitation, including snowfall both in Oregon and Washington. On the other hand, low precipitation from Southern California easterly across into Texas through the Southeast into Florida.

The Pacific Decadal Oscillation (PDO) was mentioned. This is the warm or cool temperature pattern seen in the Northern Pacific Ocean. When the ENSO and PDO are in a cool or negative phase from normal, they reinforce each other. Currently, both are generally fortifying each other. This fact, it is felt, makes this winter forecast prediction a bit stronger. So, there you have it. Cooler temperatures and a decent amount of precipitation for us. Looks like we are already there!

Let's review what happened in November 2022. These data are from my personal home weather station. Our first snowfall occurred in November. We ended up having five separate snowfalls. Total snow for November was 14.9 inches with a Snow Water Equivalent (SWE) of 1.03 inches of water. Nice way to start "winter." The all-time maximum snowfall was in 1955 at 17.5 inches. The mean snowfall is 1.3 inches. As for rain, I measured 0.79 inches on Nov. 7. A total of 2.30 inches of precipitation. The mean precipitation of November is 1.23 inches, and the maximum was in 1973 at 3.98 inches. Remember, generally wetter in a La Niña year. A high temperature of 55.1˚F occurred on Nov. 4, and a low of 10˚ happened on the 29th (just before our snow-and-blow event). Our mean was 30.2˚F. The all-time high temperature was 69˚F in 1989. The all-time low as 10˚F in 1984 (matched that at my personal weather station) and the mean is 37.5˚F.

A full moon occurs on Dec. 7 and is referred to as the Cold Moon. The December or winter solstice will fall on Wednesday, Dec. 21. For us in the Northern Hemisphere, the December solstice will mark the longest nights and shortest days of the year. After this solstice, the sun will be moving north again and we will slowly gain more daylight.