Thursday, February 20, 2020
Thursday morning dawned clear and very cold in Steamboat Springs, with a low of -19 F at the Bob Adams airport and -7 F at the top of Mt. Werner. Under sunny skies, temperatures will moderate over the next few days, first at the higher elevations where the noontime temperature is already up to 15 F, and more slowly in town where the noontime temperature is only 2 F. There are chances for snow starting Sunday as first a warm system moves near our area and then a much colder system follows for Monday and Tuesday.
The current cold temperatures are courtesy of a piece of the last storm left behind that still contains very cold arctic air. Even though a ridge of high pressure is moving over our area today and tomorrow, bringing the sunny skies, the cold air is hanging around as it is trapped under the ridge. Clear skies, light winds and fresh snow cover allow nighttime temperatures to plummet, creating a strong temperature inversion where the lower elevations are cooler than the higher elevations as the dense cold air pools in the valleys.
While solar heating grows stronger each day as the sun moves higher in the sky, it is not yet strong enough to overcome the cold morning temperatures, so look for warming first at the higher elevations.
Meanwhile, a Pacific storm approaching the West Coast has split, with the northern part of the split weakening as it is deflected to the north by the ridge of high pressure over the West. However, the southern part of the split will form an eddy off the southern California coast that will mix with some subtropical moisture from the south as it crosses the coast on Saturday. Precipitation will move through the Desert Southwest on Saturday as the warm and wet storm moves to Colorado on Sunday.
Weather forecast models have trended further north with the storm, and while the southern Colorado mountains will be favored, our area will see clouds increase later Saturday with snow chances starting Saturday night. Currently, this is looking like a modest storm with high-density snowfall, with 1-4” expected by Sunday morning in the southerly flow ahead of the storm and 2-5” possible during the day as winds swing to be from the northwest and temperatures cool on the backside of the storm.
While these eddies can sometimes linger in one place, this one will be kept moving by a colder Pacific storm that is forecast to cross the Pacific Northwest coast on Sunday. And it will grow even colder as it moves across the Great Basin and mixes with cold air from the Canadian Plains . Low intensity precipitation will likely continue Sunday night into Monday morning between the storms and ahead of the cold front expected during the first half of Monday.
Snows will become lighter and fluffier along and behind the front and briefly increase in intensity Monday afternoon. Continued lighter snowfall in the favorable moist, cool and unstable northwest flow is expected through Tuesday as snows taper off during the day. There is disagreement between the weather forecast models on the amount of precipitation, but moderate totals are certainly possible. I hope to have more certainty in my next weather narrative, which, depending on the storms, may be Saturday or Sunday afternoon.
Weather forecast models agree we dry out on Wednesday as a ridge of high pressure builds over the West, with likely cold morning temperatures in the Yampa Valley as a temperature inversion is likely if skies clear. Another weak storm grazes our area later Wednesday into Thursday as it moves over the ridge of high pressure, though experience indicates the impacts may be stronger or weaker than currently advertised depending upon the strength of the storm and the ridge.
In any case, weather forecast models agree that the ridge of high pressure moves over our area for the end of that work week and heading into the following weekend, bringing March in like a lamb with the weather leaning more towards springtime rather than mid-winter.