Three storms for the upcoming week
Sunday, September 15, 2019
After a spectacular mid-September day yesterday, this Sunday morning is warm and sunny, with temperatures running about 3 F ahead of where they were yesterday at this time. There are three weather systems that will have some impact over northern Colorado this week, with the first later Monday being the weakest and warmest and the last for the end of the work week being the strongest and coldest.
Currently, there is a subtropical disturbance near the Four Corners moving through a ridge of high pressure over the Rocky Mountains, a large and cold storm bringing precipitation to the Pacific Northwest coast and another cold and strong storm in the Gulf of Alaska. While we will see increasing clouds as the subtropical disturbance moves across southern and central Colorado today and Monday, most of the precipitation should be confined to areas to our south, though there will be a chance for a Monday afternoon shower.
Overnight lows should be above our average of 35 F on Monday and Tuesday as the clouds act like a blanket over the earth. The warm airmass will keep our highs a bit above our average of 72 F on Monday before we see some cooling, breezy winds and a good chance of showers on Tuesday as the Pacific Northwest storm is pushed across the Great Basin by the advancing Gulf of Alaska storm.
However, the storm will be deflected to our north as it crashes into and weakens the ridge of high pressure over the Rocky Mountains. Nonetheless, a weak cool front associated with the storm is forecast to push through during the day on Tuesday, with the best chance of showers along the cool front as it pushes through in the afternoon or evening.
Wednesday and the first half of Thursday should be a pleasant between-storms period as the Gulf of Alaska storm moves south along the West Coast on Wednesday and across the Great Basin on Thursday. Clouds will increase during the day Thursday as the breezy to windy southwest flow ahead of the storm draws moisture northward and over our area. Storms will become likely by Thursday afternoon and evening ahead of and along the seasonably strong cold front which is expected to pass through later Thursday.
The storm is forecast to move across Wyoming on Friday, and we will see a continued chance of showers, along with high elevation snow, in the cool, moist and unstable northwest flow behind the storm.
It looks like another nice September weekend is in store following the Friday storm, with another Pacific storm forecast to cross the West Coast around Sunday. The may affect our area around the following midweek period, though there is substantial disagreement among the weather forecast models on the evolution of the storm.
Summer-like weather returns for the weekend
Thursday, September 12, 2019
After the first fall-like cold front of the season passed through Steamboat Springs yesterday, clouds are slowly dissipating in the cool and unstable northwest flow behind the storm. Though we’ll see low temperatures for the next several days around or below freezing, warm and mostly sunny days will last through the weekend. A stronger storm is forecast to cross the West Coast early in the work week, and we may see its effects beginning as early as Monday night.
Many areas around town received about 0.4” of precipitation from the storm that rolled through town yesterday. And though I did not see snow on the ground on the upper mountain, there was a dusting in the highest trees.
Temperatures will be slow to recover today thanks to the cold airmass, with highs ten degrees or so below our average of 73 F. Clearing skies will allow temperatures to fall five or even ten degrees below our average of 37 F, creating widespread frost and the necessity to shelter any plants wished to be kept longer into fall.
Otherwise, we should see several beautiful and dry days extending through Monday, with high temperatures approaching average on Friday and exceeding average for the rest of the weekend and Monday. Westerly winds may become a bit breezy on Saturday as a weak storm moving across the northern U.S. border grazes our area.
Meanwhile, a seasonably strong and cold storm currently located in the Bering Sea moves across the Gulf of Alaska during the weekend before sliding halfway down the West Coast by Monday. We should see increasing moisture by later Monday, along with increasing southwest winds by Tuesday and the possibility of showers . There are substantial differences in the evolution of the storm among the various weather forecast models as the storm undergoes some sort of split over the Great Basin early in the work week, so forecast uncertainty is high beyond Tuesday.
Cool fronts today and Wednesday
Sunday, September 8, 2019
This beautiful and sunny Sunday morning in Steamboat Springs will give way to an active weather afternoon and evening as a storm currently in the Great Basin travels across our area today. Cooler and quieter weather will follow early in the work week before a colder, but drier, storm brings an additional round of active weather through the area on Wednesday. Cooler weather and mostly sunny skies should follow for the rest of the work week and the following weekend.
The approaching storm is currently producing rain showers in Salt Lake City ahead of the cold front moving through eastern Nevada. Clouds will increase later this morning with showers starting around mid-afternoon and continuing through the evening, before they end by around midnight after the cool front passes through.
Monday should feel fall-like with sunny skies and high temperatures several degrees below our average of 75 F. Tuesday will start sunny and cool, with frost possible in the lowest-lying areas before we see increasing clouds and the possibility of an afternoon or evening shower ahead of the next colder, but drier, storm moving across the Great Basin.
The cold front associated with the storm will move through northern Colorado later in the day Wednesday, bringing cooler temperatures and increasing showers and that will last through the afternoon and some of overnight. I would consider this our first fall front of season due to the structure of the storm and the likelihood of snowfall dusting the higher peaks on Thursday morning.
And accordingly, low temperatures on Thursday and Friday will be the coldest of the season so far, with frost likely on Thursday and freezing temperatures on Friday as the mercury dips five to ten degrees below our average of 37 F. So those late-blooming and barely mature plants of the summer will have to be protected to prolong the incredibly short growing season this year.
But we should see plenty of sun later Thursday and Friday which should persist through the weekend, with high temperatures rising from below normal on Thursday to around normal on Friday.
An additional storm develops in the Gulf of Alaska midweek and pushes onshore around Vancouver late in the work week. Any precipitation from the storm is forecast to be to our north, though we may see some cooler, but still likely dry air sink over our region during the weekend. The main effect will be the windy westerly winds that are forecast to develop over much of the west as the Vancouver storm mixes with some cold air from the northern latitudes of western Canada through the weekend.
Several cool fronts for the upcoming week
Thursday, September 5, 2019
The Steamboat Springs area is experiencing another warm and sunny summer morning this Thursday. Several cool fronts will pass through northern Colorado later Friday, later Sunday and again near the middle of upcoming work week, increasing rain chances and decreasing temperatures.
Currently, storms are spinning off the Pacific Northwest coast, the Gulf of Alaska and the Bering Sea as a strong ridge of high pressure sits over the west. There is some monsoonal moisture that is being drawn northward underneath the ridge that may produce some showers around our area later this afternoon and evening, though they will likely produce more wind than rain as the lower levels of the atmosphere are still quite dry.
While the solar heating of the earth’s surface weakens as the sun lowers in the September sky, the jet stream sinks further southward and closer to our area, coincident with a weakening of the ridge of high pressure over the west. And as the sun lowers in the sky, the polar regions rapidly cool, strengthening the jet stream and intensifying storms.
So the jet stream will carry the first storm from the Pacific Northwest across the northern Rockies later Friday, and we’ll see increasing chances for showers on Friday afternoon and overnight ahead of and along the cool front.
Temperatures will cool for Saturday, dropping from ten degrees above our average of 76 F on Friday to around average. There is some dry air behind the front on Saturday which may keep the best moisture residing to our south at bay for at least part of the day, or even the whole day. So the current forecast for Saturday is looking drier than it has the past few days, though there may still be a chance of afternoon and evening showers.
The next storm crosses the West Coast mid-weekend, and is stronger, colder and much further south than the Friday storm. There is brief ridging between the storms, which should allow for a sunny Sunday morning before the second cold front passes through later Sunday.
This will be the strongest cool front we have seen since the snowfall we saw in town on June 23. Since there will be plenty of moisture, not only from the storm itself but from the monsoonal moisture drawn northward in the southerly flow ahead of the front, there is a good chance of moderate to heavy rainfall at times from Sunday afternoon through the evening.
Skies should clear by Monday morning giving way to a beautiful and likely fall-feeling day, with low temperatures several degrees cooler than our average of 39 F and the possibility of frost in the lowest-lying areas.
More of the same is forecast for Tuesday before the third Pacific storm crosses the West Coast later in the day. This one looks to be cooler that the second, but not as wet as the monsoonal moisture is forecast to stay well to our south. There is disagreement among the weather forecast models with respect to the eventual strength and timing of the storm, but based upon the American GFS, we could see increasing clouds on Wednesday in advance of the front and a good shot of moderate to heavy rain at times later Wednesday that could continue into the overnight hours.
Thursday and Friday look to be cooler and mostly dry, though there will be a chance of showers in the cool and unstable northwest flow behind the storm on Thursday afternoon.
Weather forecast models are currently agreeing that the following weekend will be dry, though they disagree on whether temperatures will be warmer than or closer to average.
After some of the hottest days of the summer moisture returns midweek
Sunday, September 1, 2019
The weather is warm and dry in Steamboat Springs this Sunday morning, with some of the hottest days of the summer on tap for today and Labor Day. We may be a bit cooler on Tuesday as a weak cool front grazes northern Colorado before moisture begins to overspread our area starting midweek. The increasing clouds will help cool the unseasonably warm temperatures before showers become more likely starting Thursday and extending through some of next weekend.
Currently, a stout ridge of high pressure, sandwiched between a disturbance off the Pacific Northwest coast, a large and cold storm over Hudson Bay and hurricane Dorian off the east coast of Florida, sits over the western two thirds of the nation. Precipitation chances will be practically nil for today and tomorrow as temperatures soar to over ten degrees above our average of 77 F. Many locales in the west will threaten high temperature records not only for the day, but perhaps the month of September as well.
Energy ejecting out of a cold storm near the Aleutian Islands will split as it interacts with the Pacific Northwest disturbance tonight, with some racing across the northern states and some left behind as an eddy that stays off the coast.
The first piece of energy traveling to our north looks to drag a weak cool front across northern Colorado early Tuesday, tempering the high temperatures for the day a bit, though they will still be well above average.
More energy ejecting out of the Aleutian storm undergoes a more complicated split around Tuesday, with some nudging the Pacific Northwest coast eddy eastward across the northern states and some digging further south along the West Coast. The developing disturbance off the West Coast will turn our winds to be more from the south, which will draw monsoonal moisture from the south northward over our area starting on Wednesday.
Shower chances will start to increase on Wednesday, though typically on the first day of a monsoonal surge, any storms that do form will produce more wind than rain as the lower levels of the atmosphere are dry enough to force any precipitation to evaporate before it reaches the ground.
We’ll have much better shower chances on Thursday and Friday, possibly including the overnight periods, as the upper level moisture mixes downward and becomes better established.
Meanwhile, the Aleutian storm is forecast to move eastward in a rather disjointed way, creating forecast uncertainty for the weekend and the following work week. Some sort of storm off the West Coast will likely form during the weekend, even as additional Pacific energy keeps an active storm track upstream over the northern Pacific.
At this point, there may be a downturn in shower chances for Saturday before they increase again for the end of the weekend as the West Coast storm approaches. Interestingly, despite the disagreement early in the following work week, weather forecast models agree that our first fall front may approach later in the work week as the summertime ridge of high pressure over the west loses strength thanks to less solar heating and a stronger jet stream.