We’re now into the final month of 2017 and many folks have asked, “Are we going to see a White Christmas this year?”
Well, based on the current weather patterns and the fact that we have a weak, cooler than normal sea-surface temperature event, La Nina, in the waters of the Pacific Ocean, Cliff and I see about a 70 percent chance of a White Christmas across the Inland Northwest. However, we don’t expect to see the big snowfall totals later this month like we had in December of both 2015 and 2016.
November 2016 was practically snowless in the Coeur d’Alene area. But, in December 2016, a whopping 35.7 inches of snow fell. Last Christmas Day, Cliff measured 13 inches of the white stuff on the ground. In December 2015, there was more than 21 inches of snow on the ground. That was during an El Nino year as ocean temperatures were warmer than average in the Equatorial regions. Big snowfalls in December during an El Nino year are not that common, but do happen about 25 percent of the time.
Our snowfall Christmas forecast predicts a high 80 percent chance or greater of at least an inch of snow on the ground across most of Canada and much of the extreme northern U.S. north of Interstate 90 on Dec. 25.
As frigid Arctic air pushes southward into the northern and central U.S., heavier snowfalls are expected from the violent collisions between the very cold air to the north and copious amounts of moisture from the North Pacific regions as well as the Gulf of Mexico. This is a big reason why Cliff and I see a 70 percent chance of a White Christmas in our region.
Elsewhere across the country, while much of the region from about I-90 northward has an 80 percent chance of snow on Christmas Day, there is a 70 percent chance of a White Christmas across New England. Probabilities dip to 50 percent between Interstate 90 and Interstate 80, which includes most of Idaho, Colorado, South Dakota, much of Nebraska, Iowa, northern and central Illinois, northern Ohio and Pennsylvania and New York state, but not New York City. The Big Apple has only a 30 percent chance of a White Christmas this year.
Cities and towns in the central U.S. near Interstate 70 eastward to the Mid-Atlantic states likewise have around a 30 percent chance of seeing snow on the ground on Dec. 25. There is only a 10 percent chance of a White Christmas across parts of the southern U.S. this year, but anything is possible in this cycle of wide weather extremes.
Although we are in the cooler La Nina cycle, the southern U.S., including Southern California and the Desert Southwest, are not likely to have any snow as we seem to be in a warmer temperature pattern across the globe.
In other countries, much of northern Europe and northern Asia have a very good chance for a White Christmas. The northern British Isles have a 30 percent chance of a White Christmas, with a strong 80 to 90 percent probability of snow across Norway, Sweden and Finland in Scandinavia. From eastern Europe into Russia, there is a 60 to 90 percent chance for a White Christmas. Northern Italy has only about a 30 percent chance of seeing snow on Dec. 25.
In the near-term, we’re going to have a break from the wet weather pattern that was seen in November. A strong ridge of high pressure is expected to be locked in over the western states until around the middle of the month. This will mean a lot of fog, freezing fog and high temperatures near the freezing mark in Coeur d’Alene and surrounding areas.
With the high pressure system over the West this week, a frigid air mass will be spilling southward from the north over the middle and eastern portions of the country. Sub-freezing temperatures are expected all the way down into the Gulf Coastal states.
Around the middle of the month, as we get toward the normally wet “new moon” lunar phase that begins late on Dec. 17, the high pressure system will weaken and our region should start to see an increase of moisture that will include snow. However, there is a possibility that some of this moisture will fall as rain before changing back to snow. It all depends on the temperature.
• • •
Contact Randy Mann at firstname.lastname@example.org