Saturday Snow & Cold – Round 2

4:40pm Saturday Update —

The picture above was sent in from my brother who is in Sunriver, Oregon this weekend. Looks a little chilly, eh? How about those record cold overnight low temperatures this morning? Buurrrrrr!!!! Portland recorded a record low of 18F, besting the old record of 20F set in 1962. Vancouver dropped to 17F this morning. But the big winners (depending on how you look at it, I guess) is eastern Oregon where temps dipped to -25F at Meacham and -27F at Seneca. Now that is cold!

So, what about the “S” word? It has been flying around once again. After a good look at all the latest data this afternoon it certainly looks like some light snow will fly across the area this evening. One of the big reasons why this is likely to be the case is because daytime heating was capped by all of the clouds that rolled in this morning. Thus, temperatures have not climbed much higher than 33 degrees. Once darkness falls and the precipitation moves in, we will see additional cooling. Dew points are between 10-15 degrees across the metro area this afternoon. That is really cold and dry air. Once you precipitate into that air mass, two things will occur. First, it will tend to eat up the moisture at first. But once the air mass becomes saturated enough, the temperature will have fallen. I have ran some rough numbers in my head and if the precip remains light, temps wont fall much tonight. But if we can get enough moisture in here, evaporative cooling will drop temperatures into the upper 20’s. We shall see. Either way, that is cold enough to see snow no matter where you are in the metro area tonight. On the other hand, models don’t show a ton of moisture at this point, so anything that falls will be light. Later tonight, we will see more moisture across the area and that will be our best shot at accumulating snow at the lowest elevations. The NWS has a Winter Weather Advisory up for the local area and I think that is a good call.

The big question remains — when will it all change over to rain at the lowest elevations? It has been well documented that models are normally to quick to erode the cold air and it ends up holding on longer. This time I am up in the air. One model shows a fairly quick eroding of the cold layer and the other shows a much slower transition from snow to rain. If I were to take half of one and half of the other (a split) I would say the chances are good that we will see light snow most of the night and then a change to rain on Sunday. But the fly in the ointment is the one model that I trust the most (the WRF) is already 7-8 degrees to warm for the highs today. It was forecasting 40 and it made it to 33 so far. It also shows about 4-5 degrees of cooling tonight with the onset of the snow. So, in reality that could end up being 27-28 degrees tonight instead of the 34-35 which obviously is not going to happen.

So, here is my 4:40pm Saturday call —- snow and sleet (now called ice pellets) will increase tonight and last through the night. It will be light. Snow or ice pellets will change to rain tomorrow, but the timing for that change-over is up for debate. I want to get a look at the 0z models tonight after 7pm. I bet they will adjust (colder) to reflect more of what is really going on outside right now. If that is the case, it could prolong the snow on Sunday before southerly winds finally erode the cold layer away and we see a mix of rain and snow and then just rain. I wont even address the 12z NAM model which keeps us as pure snow through Tuesday as I don’t see that being the case either. There is no doubt, it will be an interesting 24 hours. Since it is my birthday today, I may not have time to post again tonight. So, enjoy whatever snow falls and maybe (for the first time in my 38 years of life) it will snow before 12 midnight and then I will be able to say it has snowed on my birthday! 🙂

Stay Tuned!

Steve Pierce

Steve Pierce

Steve Pierce is widely known as Oregon and Washington's "go-to-guy" when it comes to fast, accurate historical meteorological research and forecasts. Steve is currently the President of the Oregon Chapter of the American Meteorological Society (AMS). Steve is also recognized as a regional weather commentator and blogger who can be heard on local radio stations and seen in print media outlets across the Pacific Northwest. His Weather Blog is hosted by the Columbian Newspaper in Vancouver. Check it out! He is a third generation resident of Vancouver, Washington and holds a degree in Communications. Both sets of Steve's grandparents migrated to Vancouver during World War II. One set traveled from Lenox, Iowa to work in the Kaiser Shipyards supporting the war effort. The other set came to Vancouver from Olympia, Washington to work as educators for the rapidly expanding Vancouver School District. When the war was over, both sets of grandparents decided to stay in Vancouver and continue raising their families, as did thousands of other families at the time. Those who are most familiar with Steve can attest to the fact that weather is his true passion. His love for "all things weather" began at the age of 7 when Mt. St. Helens erupted in 1980. He was fascinated with which direction the ash plumes were headed. Then came the very powerful windstorm of Friday, November 13, 1981, also referred to as the "Friday the 13th" storm. This was the strongest storm to hit the Portland / Vancouver area since the great Columbus Day Storm of 1962! At age 11, he was asked to publish an extended weather forecast for his elementary school's weekly newsletter. In the 1980's, at age 14, Steve was the youngest of KGW-TV's local "weather watchers" and would phone in his daily Vancouver weather stats to then television meteorologist Jim Little for use on-air. Steve has lived through all of the major Pacific Northwest weather events of the past 30 years, and then some. The most notable events include; the bitterly cold winter of 1978-1979, the record setting snow storms of January 1980, the summer heat wave of August 1981, the windstorms of November 1981 and December 1995, the severe arctic blast of February 1989, the record flood of February 1996, the historic ice storm of January 2004, the Vancouver tornado of January 2008 and the record setting snow storm of Christmas 2008. Not to mention every Mt. St. Helens volcanic eruption in between. With access to the most extensive set of historical weather records available to date, Steve has personally designed and integrated a proprietary system that gives him the ability to quickly locate and manipulate weather data as far back as the 1800's. As one local Meteorologist put it, "Steve has fast access to historical weather data that is needed for media, agriculture, business, personal, historical and other climatological needs. He can quickly manipulate the data in many different ways. His forecasts are also quite accurate, especially at longer lead times." Steve also provides local storm assessments, narratives and weather presentations to the general public, as requested. In his spare time, Steve enjoys spending time with his family, the outdoors, vacationing at his family's coastal cabin and just relaxing! By the way, do you like your weather on the "extreme" side? So does Steve! Whether it is collecting damage assessment data & photos after record setting 125 mph winds at the coast in December 2007, being one of the first on the scene after the January 2008 Vancouver tornado, or feeling (literally) the awesome power of 100 mph wind gusts at Oregon's Crown Point in January 2010, Steve has experienced it all! As Steve says, "don't just love weather, live weather!" Check out Steve's personal weather website at:

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