Warm and breezy weather ahead of Sunday cool front
Thursday, September 24, 2020
Sunny skies and warm temperatures are over the Steamboat Springs area early this Thursday afternoon, with the weather staying warm and turning breezy on Friday and Saturday. A cool front on Sunday, perhaps accompanied by some afternoon showers, will then drop daytime temperatures and make Monday morning chilly enough where outdoor plants will need to be protected. We will then be sandwiched by hot air to our west and cold air to our east for the rest of the work week, with dry weather and seasonable temperatures the likely outcome for north-central Colorado.
The ridge of high pressure currently over the southern and central Rockies is forecast to be flattened by a strong Pacific jet stream moving across the Gulf of Alaska through the weekend. The jet stream will bring dry and increasing winds from the west, especially on Friday and Saturday, with temperatures staying more than ten degrees above our average high of 68 F on Friday before dropping several degrees by Saturday. Needless to say, this will not be good for wildfire behavior.
Weather forecast models agree that a cool front will move through our area on Sunday, though disagree on its strength and if there will associated moisture. It appears the disagreement is centered on how much cold air from the northern latitudes is tapped by the storm, with the European ECMWF trending toward a cooler and wetter solution as compared to the American GFS. At this point, I would expect a cooler Sunday with temperatures closer to or below average and the chance of afternoon showers around and behind the front.
Monday morning will likely bring temperatures cold enough for outside plants to need protection, but plenty of sun should warm daytime highs back to around the low-seventies.
Meanwhile, a large ridge of high pressure builds over the West Coast behind the front as a quite cold trough of low pressure forms over the Midwest. Our area will be between the two air masses, and though our weather may tilt to either the colder or warmer side depending upon the evolution of these features, it is likely that the beautiful weather consisting of cool nights (with outdoor plants still requiring overnight protection) and warm sunny days should continue for most of the work week.
Pacific energy moving over the top of the ridge of high pressure to our west is forecast to periodically bring dry cool fronts near our area at times after midweek, though there is a fair bit of uncertainty with respect to timing and proximity. At this point, other than the uncertain temperatures, dry weather through the following weekend looks likely. For what it is worth, longer-range weather forecast models do indicate the possibility of the western ridge of high pressure breaking down after next weekend.
Stay tuned for my next regularly scheduled weather narrative on Sunday for details about the cool front that day as well as well as a possible pattern change after the following weekend.
Warm and pleasant weather this week with a small chance of Tuesday showers
Sunday, September 20, 2020
Sunny skies and comfortable temperatures in the mid sixties are over the Steamboat Springs area early this Sunday afternoon. We’ll see warming and dry weather for the upcoming work week except for a small chance of showers later Tuesday. A couple of weak cool fronts are then forecast for Friday and again Saturday, with first westerly and then northwesterly winds increasing as the jet stream grazes our area.
While high temperature today should be around our average of 70 F, they should be in the mid-seventies through midweek. A weak and diffuse wave of energy and moisture will pass by from Monday through Tuesday nights in flow from the southwest, so look for some increasing clouds and the possibility of showers by later Tuesday. But chances for precipitation are low, and like last night, any showers that do form will be light.
Tuesday will also mark the autumnal equinox when, at 7:30 am MDT, the sun passes over the equator on its journey to the southern hemisphere. So while we still be losing daylight everyday through the winter solstice, we will start to lose it more slowly.
Meanwhile, a weak storm currently over the Gulf of Alaska is forecast to be pushed eastward over the work week by a stronger eastward moving storm in the Bering Sea. While both storms will pass to our north, they will be close enough do drag a weak cool front through our area Friday and a stronger one Saturday, similar to the ECMWF forecast from last Thursday’s forecast. Both will be dry, and both will increase the winds, first from the west later Thursday and then eventually from the northwest by Friday night.
Ahead of the stronger cool front on Saturday, temperatures will rise from the mid-seventies on Wednesday to the upper seventies and low eighties for Thursday and Friday. Look for increasing wildfire danger as temperatures soar to much above average along with increasing winds.
While Saturday will likely be the coolest day of the upcoming week, a ridge of high pressure is forecast to build over the West Coast during the weekend, so expect above average temperatures to return under continued dry weather. Longer range weather forecast models continue the warm and dry weather through the following work week, but stay tuned to my next regularly scheduled weather narrative on Thursday afternoon for any changes to that forecast.
Slim shower chances mid-weekend and again next week
Thursday, September 17, 2020
The Steamboat Springs area has seen a high temperature so far of 78 F under mostly sunny and hazy skies this Thursday afternoon. Winds will increase ahead of a grazing storm mid-weekend that will likely produce more wind than rain, with a leftover part of that storm eventually moving over our area during the midweek period and bringing a slightly better chance of showers. We should see high temperatures decreasing from the five to ten degrees above our average of 71 F on Friday and Saturday to the more seasonable mid to lower seventies from Sunday through the following work week.
A storm currently just off the Pacific Northwest coast is forecast to move inland this weekend, deflecting the ridge of high pressure that is currently over the Intermountain West. The smoke plume forecast over the next day shows the smoke currently over our area from the Middle Fork fire and fires over the Uinta Mountains in Utah abating by tomorrow afternoon as winds turn to be from the current northwest to the west ahead of a weak cool front for Saturday.
However, winds are forecast to become breezy ahead of and along the front, which is expected across our region later Saturday, and will not be good news for the wildfires. There is some moisture associated with the storm, but it looks high-based and brief, bringing a meager chance for showers Saturday afternoon and evening.
Winds decrease on Sunday and turn to be from the southwest on Monday ahead of a piece of the weekend storm that was left behind off the coast of California. This piece will be slowly carried over our area through midweek, and though weather forecast models are not in complete agreement on the strength of the storm as it passes over our area, it does appear we will see a weak cool front on Wednesday.
Moisture may be increasing over our area as soon as later Monday, with a slightly better chance of showers on Tuesday and Wednesday as compared to the mid-weekend storm, though chances are still not high. The strength of the wave will determine the amount of cooling we see with the front and whether the winds shift to be more from the northwest behind the front.
Incidentally, the autumnal equinox will occur Tuesday morning at 7:30 am MDT when the sun passes over the equator, so while days will become shorter until the winter solstice, the daily rate at which we lose daylight will start decreasing.
There is considerable uncertainty heading into next weekend as the European ECMWF has a faster and shallower Pacific wave grazing our area and staying mostly dry, while the American GFS has a slower but stronger and wetter storm encroaching over our area by the end of the weekend. Stay tuned to my next regularly scheduled weather narrative on Sunday afternoon to see what we have in store for the last weekend in September.
Quintessential Colorado weather for the work week
Sunday, September 13, 2020
Crystal clear blue skies and a temperature of seventy degrees are over the Steamboat Springs area this Sunday noon. After the weather excitement last week, the current spectacular late-summer weather will continue through the work week before we may see some sort of storm for next weekend.
A ridge of high pressure extending from the Intermountain West into British Columbia is sandwiched between a storm currently well off the West Coast and a vortex of cold air loosely centered over the Hudson Bay area. The storm off the West Coast is forecast to be pushed through the Great Basin during the weekend by an additional storm currently over the Bering Sea, but ahead of that we can expect the classic Colorado late-summer weather of sunny warm days and cool nights to continue through the work week.
High temperatures should run from about five to as much as ten degrees above our average high of 73 F under sunny skies. Lows should be several degrees below our average of 36 F under clear nights, with some frost possible in the low-lying areas.
A wave forecast to drop south from the higher latitudes is forecast to spin around the cold air vortex near Hudson Bay through midweek and may knock temperatures down a few degrees on Thursday if the storm is close enough to graze our area, though at this point almost all of the cold air looks like it will be confined to the Midwest and areas east.
That West Coast storm looks to begin affecting our area as soon as Friday with breezy southwest winds, which is not a good situation for our still-burning, but quieted, fires. Winds will increase further on Saturday as a weak cold front passes by, with rain showers possible from later Saturday through the night. Longer-range weather forecast models have the storm finished by Sunday with temperatures cooling to seasonable levels heading into the following work week, though disagree on whether there will be any moisture around.
Be sure to stay tuned to my regular Thursday afternoon weather narrative for more details on the possible weekend storm.
Beautiful weather returns for the weekend
Thursday, September 10, 2020
Partly sunny skies and a temperature of fifty degrees are observed in the Steamboat Springs area early this Thursday afternoon. The storm that produced the winter-like weather and strong winds on Tuesday should finally pass over our area through tonight, leaving sunny skies and warming temperatures in time for the weekend. The seasonable weather then turns hot and dry for the following work week.
That was quite the windstorm on Tuesday, with many trees down in the neighborhoods around the base of the mountain and at least one flattened stop sign in the Eagleridge area. A 56 mph gust was observed at the Bob Adams airport Tuesday morning, and the NWS public summary indicated sustained winds of 48 mph at the top of Mt Werner and 54 mph winds somewhere in Steamboat Springs.
Similar to the Routt County Blowdown in October of 1997, I’m guessing that strong easterly winds formed a mountain wave over the Continental Divide, which then broke on the lee side of the Park Mountain Range, similar to an ocean wave breaking on a beach. This created very strong and localized gusts of winds that seemed to occur in a hopscotched pattern around the neighborhood.
Additionally, the storm brought snow to the higher elevations, with about 4” at the remote SNOTEL measuring site on Buffalo Pass north of town. Rabbit Ears Pass was closed for a time Tuesday morning due to blowing snow and dangerous conditions, though the Rabbit Ears SNOTEL showed no accumulations, likely since the wind blew the snow off the measuring pad. And we did see snowflakes in town, though accumulations were confined to elevations just above the Yampa Valley floor.
The storm that brought these conditions to our area is currently located over northwest Colorado, and is forecast to pass overhead tonight and vacate our area by Friday afternoon. But we will see two chances for precipitation, first later this afternoon and this evening in the southwest flow ahead of the storm and then again Friday morning in the favorable moist and unstable northwest flow behind the storm, with some snow likely at the higher elevations.
There may be enough sun by Friday afternoon to push our temperatures into the sixties, which is about ten degrees below our down-trending average of 74 F, with nighttime temperatures around freezing tonight, which is about five degrees below our average of 37 F.
A ridge of high pressure is then forecast to build over the west for the weekend and the following work week, bringing dry air, sunny skies and warming temperatures, with high temperatures moving from the low seventies on Saturday to upper seventies on Sunday to around the low eighties for the work week.
Longer range weather forecast models agree that a storm loitering well off the coast of California will merge with a wave of Pacific energy and moisture traveling though the Gulf of Alaska and form a stronger storm that may affect our area around the following weekend, though they disagree on the timing and strength. Stay tuned to my next regularly scheduled weather narrative on Sunday afternoon for more details on that possibility, and be sure to enjoy the return of our summery weather.
