Four storms over the next week
Thursday, March 23, 2017
The storm which has brought record rainfall to Salt Lake City today will intensify as it moves east of the Colorado Rockies tonight and forms a tightly wound closed low over the southern Front Range. The track and evolution of the storm is not favorable for the Steamboat Springs area as we don’t see a strong cold front or northwest flow behind the storm; in fact there might even be gusty northeasterly winds by Friday morning. While the storm looked promising earlier in the week, I only expect 1-4” of snow on the Friday morning report.
Precipitation will end by noon on Friday as seasonably cooler temperatures return for the day. Temperatures will warm on Saturday as a transient ridge develops behind the departing storm and ahead of the next one currently timed for Saturday night.
This wave will cross the California coast early Saturday and quickly move across the Great Basin during the day as it undergoes a modest spit, starting another round of precipitation for our area around Saturday evening. Even though the storm is considerably weaker than tonight’s storm, it’s structure is more conducive for snow as temperatures are cooler and the northwest mountain-top wind behind the front is favorable for Mt. Werner.
There is disagreement among the short and longer-range models, but 1-4” of snow is possible by Sunday morning with an additional 1-3” during the day before precipitation ends by sunset Sunday.
Brief ridging is now forecast for Monday before a third storm from the Gulf of Alaska moves south across California on Monday and Tuesday, forming a closed low as it approaches the southern U.S. border. Southwest flow ahead of the storm will carry energy and moisture northeastward, eventually spreading showers over the Steamboat Springs area by Tuesday morning.
Interestingly, the European ECMWF has the same closed low, but also has some energy splitting from this wave early in the week, bringing a cool front through our area around Tuesday night. So it is not clear if we receive a relatively warm precipitation event that ends by Tuesday night, or a cooler and more productive event that possibly lasts through Wednesday.
Surprisingly, models come into better agreement in bringing another wave with a similar track to the third storm across California on Wednesday, possibly affecting our weather by later Thursday or Friday for more unsettled weather heading into next weekend.
Three storms bring precipitation back to the region starting Thursday
Monday, March 20, 2017
The near-record temperatures of the last week have moderated today as mid and high level clouds in advance of the next West Coast storm overspread the Steamboat Springs area early this afternoon. The dry lower levels of the atmosphere precluded any precipitation from reaching the ground, and this pattern will remain more or less intact for Tuesday, Wednesday and most of Thursday.
The majority of the West Coast storm is forecast to make landfall in central to southern California later Wednesday and move eastward across the desert southwest on Thursday. Models are still struggling with the storm speed and structure, but it appears that precipitation will start as rain below 9000′ or so by Thursday afternoon or night in southerly flow.
The storm crosses the Rockies Thursday night or early Friday morning as it moves east in proximity of the Colorado - New Mexico border. Winds will turn northerly, though at this point it is not clear if there will be a westerly or even an easterly component, depending on the intensity of the storm as it moves east of our area.
This storm has the potential to leave 5-10” of snow above 9000′ by the time it winds down Friday afternoon, with some snow down to the valley floor by Friday morning as the coldest air associated with the storm arrives.
Brief ridging for the first half of the weekend is likely ahead of the second storm which is forecast to move similarly to the first, though slightly further north. After it makes landfall late Saturday, it moves across the desert southwest overnight and affects our weather from around Sunday afternoon through Tuesday, with precipitation starting as rain again below 9000′ or so. The snow level will drop overnight Sunday, though it may not reach the valley floor until Monday night when the coolest air arrives.
The third storm moves southeastward form the Gulf of Alaska and crosses the West Coast on Sunday. This storm will be colder but not as wet due to its more northern origins, and may briefly form a cutoff low in the desert southwest by Monday. This is normally not advantageous for us, but energy ejected out ahead of this third storm will combine with the departing second storm and keep possibly significant snows down the the valley floor for most of Tuesday.
Another break in the weather is forecast for the rest of the next work week before another storm in this well-advertised active pattern brings the possibility of more snow for the first weekend of April.
Warm temperatures persist through midweek ahead of pattern change
Thursday, March 16, 2017
Winds increased today as a storm passed well to the north of Steamboat Springs and flattened the western ridge of high pressure responsible for our unseasonably warm temperatures. After some clouds move through tonight, the ridge will quickly rebound bringing sunny skies and near record temperatures to our region for Friday and Saturday.
Meanwhile, much further to our west off the coast of Japan, a large storm that formed this week will eject some energy that will undercut and break down the dominant Bering Sea ridge Saturday. This will force a loitering storm currently north of Hawaii eastward, and as it phases with a storm in the Gulf of Alaska the pair will bring some cooling, breezy westerly winds and the possibility of some light afternoon showers for Sunday that may produce more wind than precipitation.
By Monday, the energy ejected from the west Pacific storm will phase with some cold air moving southward through the Gulf of Alaska early in the work week, forming a storm off the West Coast. Late Sunday’s possibly unsettled weather looks more likely Monday and Monday night before the western U.S. ridge briefly reforms ahead of West Coast storm, bringing more warm temperatures to the region for Tuesday and likely Wednesday as well.
Forecast models have the West Coast storm making landfall around midweek, bringing increasing clouds to Colorado on Wednesday and precipitation by overnight. Temperatures will stay warm ahead of the storm leading to snow levels above 9000′ before the storm moves through the central Rockies on Thursday.
As might be imagined a week out, there is uncertainty with respect to the timing of the storm, with the models trending slower with system speed, as well as storm structure, with the American GFS forming a closed low that would bring moderate to heavy snowfall to the Steamboat Springs area on Thursday.
Regardless of how this storm evolves, the storm in the western Pacific is forecast to merge with and intensify the subtropical jet stream, sending another stronger, colder and wetter storm towards the West Coast by the end of the work week. Current model forecasts have another round of brief ridging ahead of this likely major storm heading into next weekend before the storm makes landfall early in the weekend and affects our area later in the weekend.
Warm and dry until next week
Monday, March 13, 2017
A Gulf of Alaska storm has pumped up a ridge over the western U.S. that will lead to very warm temperatures for most of the coming week. A small disturbance ejecting from the storm will flatten the ridge and may affect the region with clouds and possibly light showers as it moves north of the Steamboat Springs area later Thursday and Friday.
The western U.S. ridge is forecast to quickly rebound for the weekend, quickly returning our temperatures to above normal.
Meanwhile, much further to our west off the coast of Japan, a large storm will form this week that is forecast to break down the dominant Bering Sea ridge over the weekend and allow a strong subtropical jet to cross the Pacific and eventually make landfall early in the next work week.
Additionally, the polar jet stream will no longer be diverted by the disappearing Bering Sea ridge, and cold air will pour into the central Pacific from the northern latitudes, further strengthening the subtropical jet stream. This pattern change may bring the return of long-lasting wet and stormy weather to the western U.S. around next midweek.
Small storms Friday night and Sunday followed by more warm and dry
Friday, March 10, 2017
A couple of weather disturbances will move by the Steamboat Springs area tonight and Sunday before very spring-like weather returns for the following work week.
Models have come into better agreement with respect to how the polar and subtropical jet streams and the persistent Bering Sea ridge will interact over the coming week. Energy traveling down the east side of the Bering Sea ridge within the polar jet stream has formed a large low pressure system in the Gulf of Alaska, and a wave ejecting from that will move over northern Colorado on Friday night in northwest flow. Warm and dry weather will be observed again today ahead of that storm, with increasing clouds expected later in the day. The American models have trended weaker and further north with this storm, similar to the more consistent European ECMWF model, and I would optimistically expect only an inch or two by the Saturday morning report.
Clearing and drying will move over our area by Saturday afternoon and night, ahead of another wave of energy from the Gulf of Alaska storm in northwest flow timed for Sunday. This one has mixed with energy from the subtropical jet moving underneath the Bering Sea ridge, and will be a bit moister and stronger, but it is still unimpressive, and I would expect 1-4” by the Monday morning report, most of which will fall before sunset on Sunday.
More energy propagating southward in the polar jet will strengthen the Gulf of Alaska storm early in the week and pump up a ridge over the western U.S. states that will lead to very warm work week temperatures. A small disturbance may affect the region with clouds and possibly light showers as it moves over the area around midweek, but the American models have trended weaker and further north with this solution, similar to the once-again more consistent European ECMWF model.
Another wave moving through the subtropical jet undercutting the Bering Sea ridge mixes with the Gulf of Alaska storm and brings another disturbance near our area by the end of the work week. At this point, that disturbance also looks unimpressive as another round of polar jet energy travels down the east side of the Bering Sea ridge behind that storm and keeps the downstream western U.S. ridge intact.
