Thursday, December 12, 2019
Snows have started this Thursday morning in Steamboat Springs ahead of time, and will wax and wane over the next two and a half days leading to storm cycle accumulations that could total 16-32” by Saturday afternoon. The most most intense snowfall on Thursday night and then again from Friday night into Saturday morning will be accompanied by stout westerly to northwesterly winds and will make travel difficult to impossible over mountain passes. Much colder but drier air sweeps in behind the storm for Sunday and extending to midweek, with warming, especially at the higher elevations, expected for the remaining work week.
Note that I have just added some additional numerical guidance to the Snowalarm Home page that shows the temperature, wind and precipitation forecast from the Colorado Avalanche Information Center for the Steamboat Ski Area for both Thunderhead and the top of Mt. Werner over the next three days. This represents the high-resolution version of the weather forecast model that office runs every 6 hours, and is useful for getting an overview of a predicted storm. To access the data, click on ‘Precipitation Forecasts’ and scroll down the container until you see the ‘Latest CAIC Point Forecasts’ heading. Also, previous forecasts can be viewed with the ‘Previous forecast / Next forecast’ links at the bottom of the image and give a useful indication of how the forecast is trending. Note that the scale can change when navigating through successive forecasts. Be cautioned that this is one of many weather forecast models I review before making a forecast, and as such may have its own ‘opinion’ at times.
Back to the forecast, a strong Pacific jet stream is carrying subtropical moisture from around Hawaii inland and across our area. Lots of good things associated with this, including moisture and upward motion associated with the jet stream, several embedded waves within the flow and generally northwest flow which is good for orographic, or terrain-driven, atmospheric forcing over the Park mountain range. The relatively light snowfall will continue today leaving 2-4” at mid-mountain by close. However, an embedded wave brings a cool front through our area in favorable northwest flow early this evening, increasing snowfall rates to an inch or more per hour at times from sunset or so through the overnight. Along with the wind, travel will quickly become difficult to impossible tonight over the mountain passes. I would expect 5-10” overnight which would yield 7-14” of snow for the Friday morning report.
Snows are expected to at least decrease, or even end, during the day Friday, though continued windy conditions will keep travel difficult.
Snows pick up again and turn moderate to heavy Friday night and Saturday morning as a second embedded wave in northwest flow begins to move over our area. Travel will become more difficult or impossible again through that time as snowfall rates of an inch per hour or more occur at times along with continued windy northwest flow. Another 6-12” of snow is currently forecast for Saturday morning, with snowfall rates decreasing in the morning and tapering off in the afternoon. But we could see another 3-6” during the day which would make the storm total 16-32” by the time the lifts stop turning Saturday.
Though our significant snowfall will end around then, a third colder wave is forecast to take a more southern route through the Rocky Mountains, bringing significant snowfall to southern Colorado. There is some uncertainty with the track of this part of the storm, but right now we could see some light snowfall Saturday night associated with a strong cold front that will bring much colder temperatures for Sunday that will extend into the work week.
At this point, we will be on the edge of additional snow showers on Sunday, but the sun should return for a chilly and dry Monday, Tuesday and possibly some of Wednesday before warmer air associated with a ridge of high pressure behind the storm moves over our area by Wednesday.