Note: This post talks about previous years that had some similarities to our current situation and is part of a series on my thoughts for the upcoming winter. Other posts in this series can be found here.
ANALOG YEARS
Looking at analog years goes deeper than looking at the Blob and the El Niño-Southern Oscillation. These are specific years that have at least one, ideally many, meteorological patterns that these previous years had in common with the start of this season whether they be locally, regionally, or globally. Two of the analogs I bring up will have been mentioned in the Winter Weather Conference in Portland in October, but I won’t be presenting all of the ones discussed. I’ll also be bringing up two of my own to discuss.
While each of these years have some similarities to this year, it would be inaccurate to think that this winter will proceed exactly like one of the years that I bring up. Some of these analogs will be ENSO Neutral years following an El Niño, which is the case for this year. The atmosphere of the earth is a fluid that is influenced by a wide variety of things. Currently, my favorite theory of global influence on regional weather is the impact of conditions in the Indian Ocean on severe thunderstorm outbreaks on the Great Plains.
I’ll briefly discuss a few analog years below, talking about what makes them similar to this year and how that winter progressed. Each year will include some parameters for both the Tri-Cities and Pendleton. Here are the averages for those parameters so you can compare them.
Snowfall: Tri-Cities, 7.1 in. Pendleton, 12.3 in.
Precipitation: Tri-Cities, 2.95 in. Pendleton, 3.95 in.
Mean Temperature: Tri-Cities, 35.9°. Pendleton, 35.5°.
Coldest Temperature: Tri-Cities, 4°. Pendleton, 3°.
2013-2014
Snowfall: Tri-Cities, 4.7 in. Pendleton, 20.7 in.
Precipitation: Tri-Cities, 1.12 in. Pendleton, 3.16 in.
Mean Temperature: Tri-Cities, 32.9°. Pendleton, 32.7°.
Coldest Temperature: Tri-Cities, 2°. Pendleton, -6°.
This is the only known year that had the Blob present with ENSO Neutral conditions for the entire season (part of the 2016-2017 season was neutral, but it started as a weak La Niña). This winter was exceptionally dry, but provided a decent amount of snowfall (despite being below average for the Tri-Cities). December saw a strong cold snap that had morning temperatures at or below 10° for eight days straight.
In January, the biggest weather-maker seems to have been a ridge of high pressure that caused a ten-day inversion in the Tri-Cities. Inversions like this are pretty easy to point out when looking through past data because of the very small daily temperature range. During that period, the lowest temperature reached was 29° with the highest being 34°. This inversion was deep enough to reach Pendleton, which had slightly cooler temperatures. As is often the case during inversions, Meacham (located on I-84 in the Blue Mountains) was above the inversion and even got above 50° one of these days. This is typical of winter inversions, which often have warmer than average temperatures above the layer of clouds and fog.
February had another cold period at the start of the month accompanied by some light snow. Despite having decently warm conditions in the middle section of the month (temperatures hit 60° twice), high temperatures for the month came out to 6.5° below the average. Interestingly, low temperatures were actually near-average over the span of the entire month.
2003-2004
Snowfall: Tri-Cities, Unknown. Pendleton, 26.1 in.
Precipitation: Tri-Cities, 4.07 in. Pendleton, 6.80 in.
Mean Temperature: Tri-Cities, 34.3°. Pendleton, 34.6°.
Coldest Temperature: Tri-Cities, -19°. Pendleton, -11°.
This is an example of a winter that came during an ENSO Neutral period following an El Niño. The El Niño that preceded this winter can be classified as moderate, which is slightly different from the current scenario of following a weak El Niño. This year is one that seems to have lasted in people’s memories – it has even been discussed in some comments over on my Facebook page! I lived near Tacoma for this one, and it was big there, too.
The biggest weather story here is the extreme cold. January 4 got all the way down to -19° with January 5 at -18°. These shattered the previous records, which were set in 1899 and 1924, and they continue to have a firm grasp on those records. Otherwise, that winter had a fairly mild start. Most of December wasn’t exceptionally warm or cold – until around Christmas when temperatures took a quick dive. Temperatures moderated again with a nearly week-long inversion mid-January and temperatures weren’t all that unusual from there to the end of February.
Since snowfall data for the Tri-Cities is missing, I’ll take a look at Pendleton and Yakima. Pendleton had half a foot of snow on the ground to ring in the New Year, peaking at a depth of nine inches in early January. Yakima appears to have missed out on most of the snow in late-December, but started 2004 with five inches. Yakima’s deepest snow was on January 8 when they had eleven inches on the ground.
The presence of snow at the beginning of the month helped the entire Columbia Basin and Yakima Valley reach the extreme cold that was experienced. With snow reflecting the majority of sunlight back into space, the ground doesn’t get any sort of heating during the day. This means that at night, what little warmth we do have quickly radiates out and is not replaced the following day. Several days of this, coupled with an arctic air mass, makes for some very cold temperatures. This scenario is actually part of the reason why we reached below 0° in March – something that had never occurred in the Tri-Cities before.
1993-1994
Snowfall: Tri-Cities, Unknown. Pendleton, 17.2 in.
Precipitation: Tri-Cities, 2.91 in. Pendleton, 4.20 in.
Mean Temperature: Tri-Cities, 38.1°. Pendleton, 37.1°.
Coldest Temperature: Tri-Cities, 10°. Pendleton, 1°.
This winter represents an ENSO Neutral year that followed a very brief El Niño (considered to be weak). This winter was quite a bit warmer than usual, with temperatures reaching above 60° in each month. Temperatures above 60° in January certainly aren’t unheard of – it has happened in a little more than a third of the years we have records for. What is particularly fascinating, though, is that the lowest temperature recorded that January was only 24°, which is tied for the 5th highest out of the 120 years for which records exist.
Precipitation values look to have been right around average through the course of the entire winter. Pendleton recorded a large snowstorm toward the end of February that dumped 16 inches there. It seems that the Tri-Cities probably got around 4-8 inches of snow out of it based on the temperature and precipitation value for the same day, but it’s hard to tell since snowfall records are missing for that year. This is likely to have been the only decent snowstorm of that year.
1934-1935
Snowfall: Tri-Cities, 1.6 in*. Pendleton, 5.2 in.
Precipitation: Tri-Cities, 1.51 in. Pendleton, 3.19 in.
Mean Temperature: Tri-Cities, 37.8°. Pendleton, 38.5°.
Coldest Temperature: Tri-Cities, -5°. Pendleton, -5°.
*While 1934-1935 does have some snowfall data for the Tri-Cities, that data is incomplete so this number may be inaccurate.
We do not have reliable ENSO records before the 1950s, but I’m throwing this one in here because it had a similar early-season cold snap like we had this year. I actually learned about this from a Tweet from NWS Great Falls who were comparing forecasted impacts from the event this year to one that happened at the end of September 1934.
Both weather systems had pretty similar impacts here as well. This year’s system broke our record coldest high temperature recorded in the month of September. The old record that we beat (by only 1°) was the one set during that storm nearly a century ago. Precipitation values were also pretty similar.
The winter that followed had a few short-lived, thick inversions and one good cold snap, but otherwise seems to have been particularly uneventful. Snowfall was pretty minimal during the entire season. This is probably thanks to a combination of generally warmer temperatures and lowered precipitation values.
Temperatures used in this post are in °F.
