Friday, January 6, 2017
Behind the last storm and ahead of the next one, tonight will see very cold nighttime temperatures followed by a cold and sunny Saturday morning, with possible clouds later in the day.
Yet again, a strong Gulf of Alaska storm forms over the weekend. Strong southwesterly flow ahead of the storm forms the so-called Pineapple Express as it reaches back to the old Hawaii system left over from several storms ago and moves the remains eastward over a broad ridge that forms over the western U.S ahead of the storm.
Though we will see snows on hill Saturday night and Sunday, and precipitation will start out as snow in the valley, the much warmer temperatures under the ridge as well as the copious incoming moisture may lead to a rain event in the Yampa Valley from Sunday night through Monday afternoon or night.
On the mountain, there may be an inch or two on the Sunday morning report, with another 2-4” during the day and again overnight leading to a 4-8” Monday morning report.
Temperatures look to cool by later Monday or early Tuesday as a cool front passes through, changing the rain to snow in the valley and turning on the snow-machine in cooler and still windy, wet northwest flow. Accumulations could easily be in the 8-16” range or more by Tuesday morning depending upon timing of the cool front.
At this point, snows are forecast to taper off later Tuesday before another strong wave in the Pineapple Express passes through on Wednesday and Thursday and partially phases with cool air moving southward from western Canada. This is forecast to bring more wind and moderate to heavy snows down to the valley floor and again, significant snowfall totals are expected by Thursday afternoon.
There is model disagreement for the end of the work week, with the European ECMWF bringing a splitting system into the West Coast that stays mostly south of us, while the American GFS keeps that system consolidated as it moves it over our area, beginning snows again by Friday.