La Niña to be declared soon as ocean waters cool

December has been a tough month for snow across the lower elevations of the Inland Northwest. Moisture totals have been below normal as Coeur d’Alene has received over 1.50 inches of rain and melted snow through Dec. 21. The normal precipitation in Coeur d’Alene for December is 3.90 and with additional storms expected this week and through the end of the month, there is a chance that we’ll come close to that figure.

In the mountains, many of the storms that have moved through the region have been cold enough for snow. As of the weekend, approximately 90 inches of snow has fallen at the summit of Silver Mountain and over 150 inches at the top of Lookout Pass. Schweitzer has reported about 110 inches of snow so far this season. These figures are expected to climb this week as a series of storms are expected to move through the region.

Most of the storms this season have been originating from the central portions of the Pacific Ocean, rather than the Gulf of Alaska. The coldest weather this month has been mostly east of the Rockies as frigid temperatures below the zero mark have been felt across parts of the Upper Midwest near the Canadian border.

With a southerly wind flow, our temperatures will rise. Last Wednesday, Dec. 18, Coeur d’Alene reported a near record high of a springlike 54 degrees before dropping back down into the 40s later in the week.

At Cliff’s station in Coeur d’Alene, only 2.9 inches of snow has fallen for the 2024-25 season as of the weekend. The Spokane International Airport has picked up a little more snow with a total of 5.3 inches. The normal snowfall to date in Coeur d’Alene is about 23 inches.

The long-range computer models are showing more storms coming in from the central Pacific Ocean through the end of the month. The latest data is looking better for more snow in the mountains, but we’ll have either rain or snow in the lower elevations. It’s going to be close for snowfall and as we’ve said on many occasions, it’s always a temperature thing across the Inland Northwest.

The winter season has certainly been off to a slow start, but conditions may be changing. As we move into 2025 (hard to believe another year has gone by), the weather pattern may be shaping up to be colder as a more northerly wind flow is forecast to develop over the region after the New Year. Therefore, whatever moisture falls with this pattern will be in the form of snow as it will feel a lot more like winter.

One of the reasons why there is a better chance for this new development is likely due, at least in part, to the recent cooling of sea-surface temperatures. The latest information from the Climate Prediction Center states that we’re still in a “La Nada,” the in-between warmer El Niño and cooler La Niña sea-surface temperature pattern. However, climate scientists say there is about a 56% chance that a weak La Niña will form in late December or January.

Ocean waters have been close to normal over the last several months, but the latest data shows a stretch of slightly cooler than normal waters in this region, which would indicate a higher chance of a new La Niña forming soon.

The latest computer model projections are showing that if there is a weak La Niña is declared, it is expected to be short-lived and would probably dissipate around the spring season. With a very weak La Niña, it is less likely that much above-normal snowfalls across the northern portions of the country would materialize. But the forecasts for colder and snowier weather in the northern regions have not been ruled out.

Last year at this time, we had a total of 8.8 inches through the end of December. Increased snowfall in January through April did put the 2023-24 seasonal total to 51.2 inches. Temperatures in late 2023 and early 2024 were close to what we’re experiencing now. From Jan. 12-15, 2024, we had a stretch of below-zero weather with a very frigid -17 degrees in Coeur d’Alene on Jan. 13.

One of our frigid periods two years ago occurred just in front of Christmas on Dec. 22. At Cliff’s station, the low was -12 degrees, which broke the record of -8 degrees in 1983. At the Spokane International Airport, it was -10 degrees Dec. 22, 2022. The low for that date at the Colville Airport was -26 degrees and the high did not even make it above zero with a reading of -4 degrees. In Idaho, both Bonners Ferry and Moscow dropped to -20 degrees Dec. 22, 2022. The Coeur d’Alene Airport in Hayden dipped to -9 and it was a frigid -18 degrees at Spirit Lake.

Have a safe holiday and Merry Christmas! Randy Mann and Cliff Harris.

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Contact Randy Mann at randy@longrangeweather.com.