Thursday, September 26, 2019
The Steamboat Springs area is enjoying another quintessential Colorado early fall afternoon with temperatures in the mid-seventies and lots of sunshine. The aspen are sure taking their time this year, though the just-refreshed website feature photo shows pockets of good color at around the 9000′ level of the Steamboat Ski Area, with more uniform coverage above 9500′.
I expect rapid changes in color as nighttime temperatures more consistently drop below freezing, but the leaves may have a tough time staying attached to the trees as winds will substantially increase through the next week ahead of an unseasonably strong and cold storm forecast to be located around the Pacific Northwest this weekend.
We’ll see warm temperatures close to ten degrees above our average of 67 F today with some clouds associated with a disturbance well to our southwest in southern Arizona. However, a cold front currently in Montana will move south tonight and tomorrow as the northwest storm intensifies, crossing our doorstep in the late afternoon or early evening on Friday. Increasing clouds, westerly winds and a good chance of showers will result.
Whereas my last weather narrative considered cool and showery weather possible behind the front, it now looks like the northwest storm will be strong enough so that the southwesterly flow ahead of the storm will force the cold front to retreat north of our area by Saturday. So the strong and moist westerly winds from later Friday will stay strong, but will dry and turn to be from the southwest on Saturday.
A lobe of energy is forecast to eject from the strong and sprawling storm on Sunday, and this will be bring even stronger southwest winds along with some moisture. The details will depend upon the exact track of the ejecting energy, but it may be close enough to bring a chance of showers back to our area on Sunday.
After that, a building ridge of high pressure over the southeastern U.S. bulges to the northwest and deflects the additional energy ejecting from the storm to the north of our area. Much drier air in still windy southwest flow is forecast for the rest of the work week, with mostly average or a bit below average temperatures, with the coolest day either Tuesday or Wednesday when the remaining part of the storm finally brushes by.
Another storm from the Gulf of Alaska is forecast to approach the West Coast around next weekend, but we have lots of weather to get through before guessing how that storm will affect our area.
Sunday, September 22, 2019
The Steamboat Springs area awoke to a chilly 28 F low temperature early this Sunday morning, but brilliant sunny skies are quickly raising temperatures toward our average high of 70 F. The jet stream is forecast to be just to our north most of this work week, so dry and breezy weather is expected until a large storm develops to our west and brings the chance of unsettled weather around Friday.
The Autumnal Equinox (from the Latin and literally meaning equal night. i.e. twelve hours of day and night across the planet) occurs at 1:50 am MDT early Monday morning, and coincidentally this is when our average high temperature drops below 70 F until next year.
And we will see high temperatures around that average and low temperatures a bit below our average of 33 F for most of the work week as the current storm over the West Coast splits early in the work week, as best captured by last Thursday’s European ECMWF forecast. While the southern part of the split forms and eddy over the Desert Southwest that may be drawn near our area by another incoming Pacific storm around Friday, the northern part is absorbed into the fast-moving jet stream just to our north. So while the weather will remain dry, we will likely see breezy afternoons as the northern jet stream encroaches on northern Colorado.
Enjoy the pleasant and seasonable weather as it looks to turn unsettled by Friday, with storminess possible into the weekend. The culprit is a Pacific storm that is forecast to travel across the Gulf of Alaska and mix with some quite cold air from western Canada and the Hudson Bay region. As this storm travels down the west coast of North America and broadens early in the work week, it dislodges the Desert Southwest eddy eastward by Thursday.
While most of the Deseret Southwest eddy will remain to our south, moisture will increase over our area as the storm moves eastward across northern New Mexico. Additionally, cold air associated with the West Coast storm washes over the northwestern quarter of the U.S., creating a frontal boundary separating the cool air to the north and the warm air to the south that will focus precipitation.
There is enough uncertainty with how this all occurs that the forecast for our area will undoubtedly change by my next weather narrative on Thursday, but right now I would expect unsettled weather on Friday turning cooler and stormier on Saturday as the frontal boundary approaches our area. Eventually, weather forecast models agree the West Coast storm will move inland and over our area around the following midweek, with unsettled weather persisting until after that storm passes through.
Thursday, September 19, 2019
A sunny, warm and breezy afternoon is occurring over Steamboat Springs this Thursday. The winds are in advance of a large storm currently traveling across the Great Basin that will bring a mostly dry cold front through our area later Friday, along with a trailing surge of cool air on Saturday. Warm and dry are in store for Sunday and at least most of Monday before another storm approaches.
Temperatures are currently running seven degrees above our average of 70 F as warm air is drawn northward in the south-southwesterly flow ahead of the Great Basin storm. As the storm moves northeastward and closer to our area, we may see some showers develop around midnight as some energy and moisture eject out ahead of it.
Though Friday morning may start cloudy and relatively warm, with low temperatures five to ten degrees above our average of 34 F, there is some dry air forecast out ahead of the storm that may make Friday turn sunnier for a time before the cold air starts seeping into our area sometime Friday afternoon or evening, along with increasing clouds.
As was the case with the storm last Wednesday, the best moisture is ahead of the coldest air, so once again we may see some non-accumulating snows, this time above 9000′ or so, and a cold below-average-by-several-degrees Saturday morning.
A trailing wave of reinforcing cool air is forecast to arrive later Saturday, keeping high temperatures a bit below average, with another cold night forecast, requiring outdoor plants to be protected this weekend for those wishing to prolong our shorter-than-average growing season this year.
Sunday and at least half of Monday should be brilliant sunny days with high temperatures recovering to or several degrees above average, with the Autumnal Equinox, which is when the sun crosses the Equator in the fall, occurring at 1:50 am MDT early Monday morning.
Meanwhile, another large and cold storm, currently near the Gulf of Alaska, is forecast to move southeastward and cross the Pacific Northwest coast on Sunday. There is large disagreement among the weather forecast models as to the track of the storm, with the European ECMWF forming an eddy to our southwest that moves slowly eastward and then northeastward through the midweek period, while the American GFS keeps the storm moving quickly through our area earlier in the period. The faster solution would bring another cold front through our area as early as Monday night, while the slower solution advertises a more unsettled weather pattern later in the work week, perhaps most noticeable to our south.
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.
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.