Monday, October 16, 2017
High pressure is in control of the weather for almost the entire United States, and this will bring more warm and dry days with cool nights for the Steamboat Springs area through most of the work week. A quick moving storm along the northern U.S. border may knock temperatures back a bit for Wednesday, but the dry weather will persist until later Thursday when a stronger Gulf of Alaska storm crosses the West Coast and affects our region through the early part of the weekend.
As this moves eastward, southwest winds first carry some moisture northward, bringing some high and mid-level clouds to the area later Thursday and possibly some light showers by Thursday night. As the storm moves across Idaho on Friday, southwest winds will increase over our area and become breezy to windy, with showers becoming likely by later Friday ahead of a cold front currently timed for Friday night.
Showers will stay as rain in the Yampa Valley ahead of the front before changing over to snow by overnight Friday. Like the last Saturday storm, this one will also be quick moving, bringing a cool start to the weekend with showers ending early in the day.
High pressure builds in behind the storm for a nice Sunday, though there is some uncertainty for early next week regarding additional Pacific energy that will carry some more moisture and winds inland across the Pacific Northwest. This energy may sag far enough south to bring some clouds and slightly cooler temperatures for Monday and Tuesday, or stay north of the area for less clouds and warmer temperatures.
It appears La-Nina is back in the news, as the National Weather Service issued an advisory last Thursday indicating a 55%- 65% chance of a La-Nina winter. El-Nino is a warming of the ocean waters in the southern Pacific, while its counterpart, La Nina, is a cooling of those same waters, and its appearance can affect global weather patterns. Closer to home, El-Nino is associated with a strong, relatively stationary ridge of high pressure in the eastern Pacific, while La-Nina has a much suppressed or even absent ridge.
While some weather forecasters insist that all of Colorado is affected by El-Nino or La-Nina, the fact is that northern Colorado is not well correlated with either. During El-Nino years, the location and amplitude of the ridge of high pressure in the Pacific is critical, and the Steamboat Ski Area may be in favorable northwest flow if the ridge is far enough west, or benign weather if the ridge is further east and closer to our area.
However, the suppression or absence of the ridge during La-Nina years means that storms moving across the Pacific are not influenced by a relatively stationary weather pattern. This tends to keep the storms moving, and long stretches of either quiet or stormy weather are less likely. In my view, an accurate seasonal forecast for northern Colorado based upon the slightly-better-than-chance probability of a La-Nina event, combined with the absence of strong correlations in our area to that event, is impossible.
Thursday, October 12, 2017
A large storm currently located in the Pacific Northwest will send several cool fronts through the Steamboat Springs area starting today, with the last one on Saturday the strongest. Gorgeous warm and dry fall weather will return Sunday and last through at least midweek.
Winds have picked up ahead of the first front today as southwest flow increases, and conditions will stay breezy to windy through the first half of the weekend. Friday will be similar to today, though with less clouds as drier air overspreads the area behind the front.
On Saturday, a much stronger and sharper cold front will blast through the area in the morning or early afternoon as the Pacific Northwest storm moves across the northern Intermountain region. Temperatures will drop ten or twenty degrees fairly quickly behind the front as gusty winds veer from the southwest to the northwest and clouds increase.
There may be enough moisture for showers, and the the air will be cold enough for snowflakes in the Yampa Valley behind the front. After our brief encounter with Indian Summer this week, Saturday could feel like quite the raw day.
But the cool down will be short lived, and after a cold start to Sunday morning, a warm and very dry airmass settles over the West, promoting the return of Indian Summer through at least midweek.
Uncertainty emerges for the end of the work week as a storm approaches the West Coast in strong westerly flow. Models are struggling with the its timing and strength, but some sort of storminess is expected for the end of the work week or the following weekend.
Monday, October 9, 2017
The unseasonably cold storm discussed in Thursday’s forecast moved in about 12 hours faster than originally forecast, arriving in the Steamboat Springs area around sunset Sunday and leaving by noon today. Temperatures fell to 14F at the top of Mt. Werner last night and mountain-top winds were mostly from the east, limiting precipitation as the easterly winds moved down the slopes of the Park Range and dried the airmass.
Drier air has moved in behind the storm, and after the coldest morning of the season Tuesday, temperatures will warm through midweek yielding some more spectacular fall weather.
Several waves of energy and cool air will rotate through the Gulf of Alaska and move along the northern U.S. border from Thursday through the weekend. While most of the weather will stay to our north, temperatures may be knocked back a bit and winds will become breezy as the cool air grazes our area each day.
Some uncertainty in the forecast appears for the weekend, as some of the Gulf of Alaska energy takes a more southern track through the Great Basin. Models are still struggling with how much energy splits southward early in the weekend and whether the bulk of the energy moves across our area in one piece or two over the weekend. Whether we see a cooler Saturday afternoon with some showers or a warmer Saturday with showers holding off until later Saturday or Sunday is yet to be determined.
Thursday, October 5, 2017
A dry cool front for Friday will precede a nice weekend ahead of another snow event on Columbus Day in Steamboat Springs. The rest of today will feature a brilliant fall day with warm temperatures and sunny skies.
They dry storm currently located in Nevada and discussed in Monday’s forecast will move across northern Colorado on Friday. Temperatures will fall from above average today to below average tomorrow, and there may be some afternoon showers as the atmosphere destabilizes.
After a cool start to Saturday, dry weather with mostly sunny skies and above average temperatures will grace our area through the weekend.
However, like the last storm, another storm that forms in the Gulf of Alaska during the weekend mixes with some cold air from western Canada and the polar region, and travels through the Great Basin on Monday. The southwest flow ahead of the storm will battle the cold air north of the storm, with dry, warm and possibly breezy conditions ahead of the cold front. Numerical weather models have struggled with the timing of this storm, but current forecasts bring the front through sometime on Monday. At this point it is uncertain during what part of the day the front arrives, so we may sneak in another nice day, or not.
The air will be quite cold, and it may be an all-snow event in the Yampa Valley that will extend through Monday night. Any precipitation that falls as rain should quickly change over to snow as temperatures plummet, and accumulations are again expected in the valley, with more significant accumulations at the higher elevations.
Clouds may linger on Tuesday as the storm moves east of our area, with another cool day expected. Cold morning temperatures behind the front will be experienced on Tuesday, and again Wednesday if skies clear Tuesday night.
As was the case this week, warmer and drier air washes over our area for most of the rest of the work week.
Lots of uncertainty emerges for next weekend as another storm forms in the Gulf of Alaska and splits as approaches the Pacific Northwest coast around the end of the work week. Numerical weather models disagree on the amount of splitting and whether the southern part of the split loiters offshore or moves inland, with one solution keeping us warm and dry and the other bringing at least unsettled weather into Great Basin and eventually our area for next weekend.
Monday, October 2, 2017
The strong winter-like storm that is still gripping the Steamboat Springs area has left 19” of snow containing about 2.4” of liquid water at the top of Sunshine Peak near Patrol Headquarters, as shown by the current Steamboat Powdercam, and about 6” on my deck near the base of Mt. Werner. In the Yampa Valley, the rain that started around 2:30 Saturday afternoon left about an inch of water by Sunday morning. By mid-morning Sunday, the rain had changed to snow, certainly much earlier than my Thursday forecast, and continued through Monday morning, leaving about another inch of liquid water in the valley.
The cold air associated with this storm, sourced from the North Pole, was not to be slowed by the southwest flow aloft, and snow levels dropped faster and further than originally forecast. Snow showers will taper off through the afternoon today, with another weak round of showers possible around midnight.
Some drier air should move over our area after midnight, and if skies clear, temperatures will fall to the lowest levels of the season so far. Below normal temperatures will persist into Wednesday as the sun’s energy goes into melting the snow rather than warming the atmosphere.
As this storm lifts to our northeast by midweek, another storm moving southward from British Columbia briefly stalls in Nevada through midweek. This will keep southwest flow over our area until the end of the work week and we will see warming temperatures under continued mostly sunny skies.
As energy traveling across the Pacific crosses the British Columbia coast around Friday and energizes the jet stream, the Nevada storm is ejected to the east and northeast, moving over or near our area sometime on Friday. This storm will be quite dry, likely with no precipitation, but it should knock temperatures back a bit for Friday.
Uncertainty emerges for the weekend as it is not clear how strong and how far south the Pacific jet stream will travel as it sags southward across the Intermountain West after crossing the West Coast. Earlier forecasts had significant warming and drying over Colorado for the weekend, but current numerical model forecasts now have the jet stream pushing further south, and this will likely limit the previously advertised warming and drying as cooler air and clouds lurk to our north.