Thursday, March 9, 2023
Temperatures are in the upper twenties in the town of Steamboat Springs and low teens near the top of the Steamboat Ski Resort under clearing skies late this Thursday morning. The mostly sunny skies this afternoon will be replaced with a warm and wet Pacific air mass on Friday, possibly bringing rain below mid-mountain during the day and evening. Colder air arrives overnight Friday, turning any liquid precipitation to snow, with the bulk of the significant snow at mid-mountain and above over by Saturday afternoon. Snow showers may persist through the rest of the weekend.
The two inches of snow reported at mid-mountain today and three inches up top were due to an ejecting wave of energy and moisture from a persistent area of low pressure currently off the Pacific Northwest coast that had earlier formed an eddy. Our weather gets very interesting starting on Friday as a stream of subtropical and tropical moisture referred to as an atmospheric river combines with winds on the south side of that Pacific Northwest eddy and slams into West Coast later today.
Ahead of that, skies will continue to clear today for a mostly sunny afternoon. But we will see a warm and wet Friday after the atmospheric river dumps impressive low-elevation rain and high elevation snow on California and moves overhead. As is often the case in March, the low elevations will struggle with cold enough temperatures for snow, and rain or a rain-snow mix is likely below mid-mountain on Friday and Friday evening, with a dense 2-5” expected by sunset at and above mid-mountain.
That Pacific Northwest eddy is forecast to be forced eastward on Friday by another eddy forming in its place, and will move over our area around midnight on Friday. Much colder air will accompany the former eddy, with any liquid water turning to snow at low elevations and mountain top temperatures dropping from near thirty degrees ahead of the cold front toward ten degrees by Saturday morning. Winds will become strong and gusty along the front, though should quiet down by sunrise on Saturday. We could see another 4-8” by the Saturday morning report, with the snowfall becoming progressively less dense toward morning. And there may be another 1-4” of light and fluffy snowfall by noon.
The cold front will push the best moisture to our south, keeping the chance of snow showers going through the rest of the weekend as we are on the boundary between the warm and moist air to our south and the cold and drier air to our north. We could see 1-4” of additional snowfall Saturday night and that again during the day Sunday.
A final weak wave may move across Sunday night, and if that happens we could see another 1-4” fall in the favorable northwest flow. A ridge of high pressure then looks to briefly build over our area to start the work week ahead of the new Pacific Northwest eddy for some nice weather, though that may be short-lived as another significant storm is possible around midweek. I’ll have more details about that in my next regularly scheduled weather narrative on Sunday afternoon.