Precipitation chances finally appear near the end of the work week
Sunday, October 18, 2020
Similar to yesterday, the Steamboat Springs area is seeing temperatures in the mid-fifties under cloudy skies early this Sunday afternoon, with even a few drops of rain this morning. Breezy afternoons and warming temperatures will continue for most of the work week as we see more sun before some precipitation chances finally appear for the end of the work week. But the best news is a moderate winter-like storm is now possible for Sunday.
The weather pattern over North America is currently dominated by a strong vortex of cold air over Hudson Bay that extends southwestward into the central U.S. and a flat ridge of high pressure over the Gulf of Alaska. An active jet stream between the cold air to our northeast and the warm air to our southwest has been over or near our area this past week, and that looks to continue for most of the upcoming week.
As some warmer air is forecast to move overhead for the first half of the work week, we should see more sun than we have this weekend, though there may still be some clouds around as the driest air stays to our south. But look for temperatures to stay five to even fifteen degrees above our average high of 58 F, with Wednesday likely being the warmest and sunniest day of the week.
Meanwhile, a storm cut off from the jet stream near the dateline is forecast to merge with a strong eastward-moving storm currently over Japan by midweek and amplify the ridge of high pressure over the Gulf of Alaska. Pieces of energy ahead of and within this merged storm are forecast to travel over the ridge of high pressure and mix with the cold air over the Canadian Plains starting midweek.
While weather forecast models agree that these waves will produce a pattern change starting around Thursday, there is uncertainty with respect to their timing and strength and what eventually passes over our area. Right now, we have increasing chances of precipitation later on Thursday as the first storm passes mostly to our north. Precipitation amounts will likely be modest, but enhanced or diminished by the storm moving further south or north, respectively.
There may be another wave that brings precipitation to our area on Friday night, according to the American GFS, though the European ECMWF has that wave weaker and further south.
But there is agreement that a strong winter-like storm develops late in the work week as it slides down the North American west coast, and forecasts have this storm affecting our area as soon as later on Saturday. If current forecasts hold, this looks to be a snow event that should bring winter-like conditions to our area by Sunday morning.
The bulk of the snow looks to fall on Sunday, with the cold air staying put for Monday and possibly Tuesday as the precipitation becomes more showery. Considering the evolution of this mercurial storm in the past longer-range weather forecast models, I expect changes to the forecast as the event grows closer. Stay tuned to my next regularly scheduled weather narrative on Thursday afternoon for updates on our looming winter-like storm.