Sunday, March 19, 2023
Chilly temperatures in the low teens and sunny skies are over the Steamboat Springs area at all elevations this Sunday mid-morning. Even though the first day of spring is tomorrow, the weather has other ideas as a series of wet and increasingly cold Pacific systems bring chances for snow for each day of the work week that will continue into next weekend.
Our gorgeous three day stretch of mid-winter-feeling weather this weekend ends in a dramatic fashion for the first day of astronomical spring, which occurs at 3:24 pm MDT on Monday during the vernal equinox, when the sun crosses over the equator for its northern hemisphere summer stay.
A very active weather pattern currently spans the entire Pacific ocean, with chunks of very cold air continually breaking away from Siberia and eventually mixing with relatively narrow but very wet atmospheric rivers from the subtropics.
A cold storm currently in the Gulf of Alaska has mixed with an atmospheric river near Hawaii, colloquially known as the Pineapple Express, and a wave of energy ejecting out of the storm is bringing another round of heavy precipitation to the Sierras. The wave will cross the Great Basin tonight, and we should see increasing clouds later today before precipitation breaks out during the day Monday over our area.
Winds at mountain-top level will shift to be from the current southwest direction to the west later Monday and eventually our favorable northwest direction overnight. While it is always tricky predicting snowfall in the generally unfavorable southwest flow thanks to winds downsloping off the Flat Tops and drying the atmosphere, 1-4” of snowfall is possible in the afternoon, with another 3-6” likely overnight at mid-mountain at the Steamboat Ski Resort.
Snowfall should end for a short time during the day Tuesday behind the wave, and there may even be some sun ahead of the next more significant precipitation event on Wednesday. Another cold storm with Siberian origins currently east of Japan is forecast to cross the Dateline on Monday and force the Gulf of Alaska storm bodily eastward and across the central California coast on Tuesday.
More of the Pineapple Express is forecast to be incorporated into the storm which will eventually span the entire West by Thursday after energy either ejects out ahead of it or rotates around it. Right now, the most intense precipitation should be between Tuesday night and Wednesday afternoon, first in winds from the southwest and then the west if the center of the storm reforms over Wyoming Wednesday night as currently forecast.
I would expect 1-4” of snowfall at mid-mountain by the Wednesday morning report, with another 4-8” for the Thursday morning report. Cool and snow-showery weather looks to continue for the rest of the work week as that Japan storm eventually reaches the Pacific Northwest coast on Thursday and we see favorable cool, somewhat moist and unstable northwest flow between the incoming and departing storms.
It currently looks like that Japan storm will eventually move near our area to start the following weekend for more snow chances, though there is a lot of weather to get through before there is some certainty to that forecast. So be sure to check back Thursday afternoon for my next regularly scheduled weather narrative where I will focus on that next weekend storm.