The question comes up every year, will we be seeing snow this winter? The last 2 years have been rather generous in terms of snowfall and cancellation of school and Central students would be happy to see a couple days to frolic in the winter weather.
Portland is not known for its winters, when we see snow it’s a big deal, but most of the time it’s scarce and does not hang around for long. The Koppen Climate Classification Subtype has Portland having a CsB Mediterranean climate, which in weather terms is a “dry summer subtropical climate.” This climate is known for dry and hot summers and cool and rainy winters. On average, Portland usually receives 4 inches of snowfall each winter, usually short lasting and spread out over 2 or 3 days. However 25% of winters in the last 100 years have received no snowfall at all. Portland has one of least snowy winters of any non sun belt city.. The last two winters in Portland have been interesting, both 2016-17 and 2017-18 have been La Niña winters meaning pacific ocean waters were cooler than average. A common misconception is La Niña = Snow, this isn’t true. While in 2016-17 we were given almost 20 inches of snow and 10 days off of school, 17-18 was rather tame in comparison with just one major snow event totalling around 2 inches. 2018-19 is predicted by many organizations to be a “El Niño” winter, El Niño being the opposite of La Niña. The National Weather Service here in Portland says there is a 80% chance that El Niño forms and continues from winter into spring 2019.
El Niño signals high temperatures in the pacific ocean, which usually translates to warmer temperatures. The last El Niño winter was 2015-16, which was the 4th warmest winter on record and produced little to no snow. However, similar to La Niña, El Niño does not mean no snow and no school closures. The 2008-09 El Niño dropped an unexpected 2 inches in mid december, paralyzing Portland and closing schools for 3 days. A while back in 1997-98, El Nino dropped almost 9 inches spread out across 3 major snow events. The 2017-18 winter was a La Niña winter, but for the 5th consecutive winter the Pacific Northwest was without an arctic blast, which is a very low pressure system that, thanks to the jet stream winds, will extend down into parts of the U.S. occasionally. The midwest already saw a mini blast over thanksgiving weekend, abnormal for November. If the PNW was to see an arctic blast this winter at the right time, snow and frigid temperatures should be expected, yet 5 straight years without a blast could become 6 fairly easily.
If you’re into superstition and don’t believe the National Weather Service and TV meteorologists’ plea that this will be a warm winter, I have some theories for you. Lots of people on the OregonLive 2018-19 winter preview subscribe to the five year rule. In 2013 the city of Portland didn’t receive too much snow, due to a rather unexpected high temperature surge, if that surge hadn’t happened, we could have counted on rather heavy snowfall. Despite Portland missing out, Mt. Hood received the most snow since 5 years before in 2008. The 2008-09 winter was one that won’t soon be forgotten by Portland residents. Nearly 24 inches of snow was dropped on the valley from December to January, causing up to 2 million dollars in damages across Multnomah county but also bringing joy to many kids hoping to see a white Christmas. Following the 5 year pattern, the 2003-04 winter brought 12 inches to the Portland metro area from December to January, comparable to the “snowpocalypse” that canceled 9 days of school just 2 years ago. This pattern is fun, imagining what we could see this winter, yet the National Oceanic and Atmospheric Administration has 80% confidence that we will see a warmer than average winter this year.
If you are a Central student who is purely focused on days off, no matter how we get them, a factor to take into account is the devastatingly low preparation the City of Portland has for snow. Yes, Portland gets less snow than deep south city Nashville, Tennessee, but that does not mean we can be ill prepared for snow every year, yet every year we are. 2 years ago when we received pre Christmas snow, we were out of school for 4 days combined because the city had no idea what to do. The afternoon of wednesday December 14th, 2016, we received almost 2 inches of snow by 5pm, drivers and the city were not ready. By 10pm, students were still stranded at school, thousands of cars were abandoned on freeways and hills had become a slippery mess leading to hundreds of accidents. It got so bad that the state of Oregon issued a state of emergency. They would issue another just 4 weeks later for the “snowpocalypse.” It is a running theme to see the Portland metro area completely paralyzed and unprepared for snow, but that also seems to be a benefit in disguise for students hoping for days off. Unpreparedness gave Central students 3 days off of school last year and 9 the year before.
Realistically, we can expect 1 or 2 snow/freezing rain events this year. That could mean a few days off or many. We are certainly experiencing a cold December so far, with lows entering the 20s at night. That could possibly be a sign of things to come.
Weather in general is hard to predict, to make sure you are keeping up on the latest developments in our area be sure to check out the National Weather Service Portland for the most detailed forecasts. Another thank you goes to the Fox12 Weather blog, for their amazing archive and graphics showing the winter weather history of Portland.