Snowy this week with moderate arctic intrusion
Sunday, January 1, 2017
The good news is the bitter cold forecast in the last discussion will likely be warmer and of shorter duration and we should still see snow for much of the work week in the Steamboat Springs area. The bad news (from a forecasting perspective) is there is still considerable uncertainty in the near term among the numerical models, which is unusual since a consensus usually emerges this close to an event.
A strong storm along the Pacific Northwest coast has phased with some bitterly cold air from western Canada originally sourced from Siberia. The storm is forecast to split and elongate to the west and east underneath a ridge of high pressure in the Gulf of Alaska, eventually forming a frontal boundary that encroaches over our area around Monday. The major uncertainty lies with how far west and south energy from this storm propagates in the eastern Pacific.
Models do agree that cold air will move over the region from Monday through early Thursday, though the splitting storm will carry the coldest air to our north and east. The European ECMWF has a reinforcing wave of cold air moving over the area late in the work week while the American GFS keeps more energy in the eastern Pacific, pumping up a flat ridge over the Great Basin and moving copious Pacific moisture inland under warming temperatures.
Light snow should start overnight on New Year’s Day, with up to an inch or two of snow for the Monday morning report, and pick up for a time during the day as cold air invades the area. However, there is no sharp frontal boundary which reduces the likelihood of heavy snow and the mountain-top winds are from the west, which is not an ideal direction for Mt. Werner. But the snow is persistent and lasts through the overnight hours, so I would expect 4-8” of snow by the Tuesday morning report.
Light snow will continue through Tuesday with another 3-6” forecast for Wednesday morning before another push of very cold air moves over the area later Wednesday into Wednesday night. Though the winds veer to a more favorable northwest direction, a ribbon of dry air lurks just to our north so snows should wind down during the day and overnight with another 1-4” expected during Wednesday.
The forecast for Thursday is dependent upon the track of cold air traveling southwestward from western Canada as discussed above. The European ECMWF keeps the end of the work week drier and colder, while the Amercan GFS brings moderate to sometimes heavy snows inland under a warmer Pacific airmass for later Thursday and Friday.
Lot’s of uncertainty, so stay tuned for my late-week weather discussion next Thursday or Friday.
Arctic freeze and snow follows mostly dry weekend
Thursday, December 29, 2016
Three storm will affect the Steamboat Springs area weather over the next week, with the last one opening the door to frigid air from Siberia and the North Pole for the next work week.
Ahead of that, Friday looks similar to today, with sunny skies and another chilly start to the morning. But upstream, the first storm currently spinning west of southern California will be forced eastward across the southern Great Basin by a piece of the second storm moving south from the Gulf of Alaska. While mid and high clouds from the first storm look likely Saturday, the bulk of the precipitation will stay in Arizona and New Mexico.
Meanwhile, the second storm, having split earlier in the week and leaving energy behind a chunk of energy that eventually migrates to the north of Hawaii (and which may eventually visit our area), undergoes another split as it is forced to the Pacific Northwest coast by the third storm on Friday. The end result is that after the first storm passes on Saturday, unsettled weather is forecast for Sunday as first the northern piece of the second storm stretches over our area followed by the southern piece. Again, the bulk of the precipitation is forecast to stay south of our area in Arizona and New Mexico, but light snow is possible during the day Sunday.
Meanwhile, the third storm phases with some bitterly cold air from western Canada originally sourced from Siberia, and elongates to the west and east, eventually forming a frontal boundary that encroaches over our area around Monday. There is uncertainty with respect to how much Pacific moisture overruns the frontal boundary, but light to moderate snows are currently expected for Monday and Tuesday, possibly extending into Wednesday.
What is more certain, though, is the cold. Frigid air will pour into the region behind the front, creating a bitterly cold Tuesday and likely colder Wednesday and Thursday. Low temperatures in the minus tens and twenties are possible along with highs below zero if the coldest air moves over our area.
Even though the cold temperatures will moderate somewhat after then, below average wintertime temperatures are expected to last into the following weekend with little precipitation.
The forecast is likely to change with the third storm being so dynamic, so stay tuned for my early-week weather discussion next Sunday or Monday.
Midweek storm followed by stormy period starting this weekend
Monday, December 26, 2016
After fresh snow and a clear Monday night, the Yampa Valley will start out quite cold Tuesday morning, though temperatures should moderate during the day under sunny skies, especially at the higher elevations.
The next wave in the Pacific jet stream will move across the Pacific Northwest on Monday and the northern Rockies on Tuesday, bringing breezy conditions to northern Colorado in cool and moist northwest flow. Light to moderate snows are likely for Wednesday before tapering off overnight, with 3-6” expected on the Thursday morning report.
Meanwhile, a storm in the eastern Pacific spits in the Gulf of Alaska midweek. The southern piece is forecast to form a closed low that eventually meanders north of Hawaii while the northern piece allows a flat and dry ridge to move over the Intermountain West for Thursday and Friday for a nice couple of days.
By Friday, the northern piece of energy undergoes its own split, with the southern piece traveling south along the West Coast as it dislodges another meandering storm off the coast of Baja eastward. While models initially forecast this storm to stay to the south of the Steamboat Springs area, current forecasts have mid and high clouds encroaching on our area Friday night and light snows for much of Saturday. The further south track initially forecast would keep our area precipitation-free for Saturday if it comes to pass.
Another Pacific storm moving across the Aleutian Islands on Friday phases with some very cold western Canadian air and most of the storm drops southward from the Gulf of Alaska along the Pacific Northwest coast. As was the case with preceding wave, this very cold storm pushes the original storm to it’s south eastward, bringing another round of light to possibly moderate snows to our area that peak around Sunday night. Again, there is uncertainty with regards to the northern extent of the precipitation.
Snowy weather will likely continue into the following work week as the strong Pacific Northwest storm elongates to the west and east. This brings a frontal boundary near our region as early as Monday morning that could be a productive snow-maker as energy is ejected along this boundary from the Pacific Northwest storm. The exact placement of this frontal boundary will likely change in coming model runs, so stay tuned to the end-of-week forecast on Thursday or Friday for updated details.
Cold and snowy for Christmas Day
Friday, December 23, 2016
A strong storm from the Gulf of Alaska is currently affecting the West Coast and will cross the Great Basin on Saturday, bringing a cold and snowy present to Steamboat Springs for Christmas Day. Ahead of the storm, mid and high level moisture carried by windy south to southwesterly flow will overspread the area.
The warm and windy pre-frontal environment looks to last until early Christmas morning, with the American GFS slowing the system down more similar to earlier model runs from the European ECMWF. Precipitation should start between midnight and sunrise, and though models keep a tongue of warm air around as Gulf of Mexico warmth and moisture wrap around a strong surface low in northeastern Colorado, it does look cold enough for mostly snow in the valley.
I would expect only slight accumulations of dense snow for the Sunday morning report due to the later arrival of the cold front, perhaps in the 1-4” range. The front will barrel through the area Sunday morning with a burst of snow, wind and rapidly falling temperatures. Mountain top flow will quickly veer to the northwest behind the storm which is very favorable for Mt. Werner, and moderate to heavy snows will occur through the day, making for excellent Sunday afternoon skiing in winter storm conditions. It will, however, make for difficult or sometimes impossible travel conditions.
Snow will gradually weaken overnight until lingering snow showers end around noon on Monday. I would expect 5-10” by the Monday morning report with another 1-4” between report time and noon.
After a clear Monday night, the Yampa Valley will start out quite cold Tuesday morning, though temperatures should moderate during the day under sunny skies.
The next wave in the Pacific jet stream will move across the Pacific Northwest on Monday and the northern Rockies on Tuesday, bringing some moisture to northern Colorado and leading to lightly accumulating snow showers for all of Wednesday.
Thursday and possibly Friday might be in-between days as there is considerable model disagreement for next weekend. The American GFS phases another Pacific wave with some very cold air in western Canada and brings some sort of storm through the area during New Year’s weekend, while the European ECMWF builds a ridge over Colorado.
Light snow on Wednesday followed by Christmas storm
Monday, December 19, 2016
The Steamboat Springs area will see some warming on Tuesday that will be most pronounced at higher elevations as a temperature inversion at the lower elevations (where temperatures increase rather than decrease with height) keeps the valley cool. An unimpressive wave in fast westerly flow traverses the northern Rockies by Wednesday and drags the southern end of a cool front through northern Colorado around Wednesday morning. I expect there will be some snow, though amounts will likely be less than an inch or two through the day.
The sun will return for Thursday before an intensifying storm moving through the Gulf of Alaska forces a closed low currently west of Baja eastward, with forecasts keeping the storm track south of Colorado and bringing precipitation to Arizona and New Mexico Thursday and Friday.
The moisture from the southern storm is forecast to stay mostly south of our area on Friday for another mostly sunny day before windy southwesterly flow ahead of the incoming Gulf of Alaska storm drags some lingering high-level moisture from the old Baja storm northeastward, bringing clouds and noticeably warmer temperatures by later Friday and Saturday.
There is uncertainty with the timing, but according to the faster American GFS, the Gulf of Alaska storm makes landfall around California late Friday and crosses the Great Basin early Saturday, bringing a strong cold front with rapidly falling temperatures through Colorado around Christmas Eve. Though details are likely to change this week, it looks like a 6-12” of snow may fall by the Christmas Day morning report, with additional lighter accumulations during Sunday in the cold, moist and unstable northwest flow behind the storm.
Snow showers may linger for the rest of Christmas Day night before ending on Monday, followed by drying and warming that will last through Tuesday.
