Warm and dry this week interrupted by cold front on Thursday
Monday, October 23, 2017
A weak storm that passed through the Steamboat Springs area earlier today has exited the region, with skies clearing and temperatures rebounding behind the quick-moving disturbance. Dry weather and warming temperatures are on tap for Tuesday and especially Wednesday ahead of another storm timed for Thursday. Winds may become breezy Wednesday afternoon ahead of the storm.
This storm has trended further east and drier with successive numerical model runs, but the forecast for colder temperatures has persisted. The front is forecast to pass through northern Colorado during the day Thursday, accompanied with some light snow showers down to the Yampa Valley floor.
Cooler than normal temperatures will persist for Friday as trailing energy reinforces the cool air and keeps some clouds around, but there should be no additional precipitation.
The weekend look warm and beautiful ahead of a possible early-week storm which will contain the remnants of typhoon Lan. Currently affecting Japan, the storm will be absorbed by the Pacific jet stream and move over the top of a ridge of high pressure that builds near the West Coast this weekend.
Significant forecast differences persist between the numerical weather models, and it relates to the location and size of the West Coast ridge. The American GFS keeps the ridge strong and most of the storm travels north and east of our area in northwest flow, with a glancing blow of cooler air and some precipitation later Monday. The European ECMWF is more aggressive with the storm, moving it through the ridge and keeping it further south and west. Ironically, the more aggressive solution keeps Monday nice for our area as the storm digs into southern California, before possibly phasing with some cold air from the north around Tuesday as it moves along the southwestern U.S. border.
I have no preference for either model at this point, and would suspect some sort of compromise solution emerges, which I will write about in the Thursday forecast.
Quick moving late Friday storm followed by seasonable weather
Thursday, October 19, 2017
After another gorgeous fall day today, the Steamboat Springs weather for Friday will be changing thanks to a storm currently crossing the Pacific Northwest coast. As the storm moves across the Great Basin tomorrow, moisture and winds will increase ahead of a sharp cold front, similar in strength to last Saturday’s storm. There may be some rain showers ahead of the front tomorrow afternoon, but most of the precipitation will be in the form of snow along and behind the windy cold front Friday evening and overnight as temperatures plummet over twenty degrees.
Snow showers will end Saturday morning followed by partly sunny skies, breezy conditions and relatively cold temperatures. We will get some warming for the first half of Sunday before another storm, rotating through the Gulf of Alaska, travels along the U.S. - Canadian border and brings another surge of not-as-cold air and some clouds for later Sunday.
The storm is forecast to sag into the northern Great Plains on Monday, and while showers will likely stay to our north and east, clouds and some cooler will stick around into Tuesday.
Much drier air and much warmer temperatures are expected for Wednesday ahead of another Gulf of Alaska storm approaching our area from the northwest. Numerical weather models have trended further south and west with this storm over the last few runs, and at this point it looks like another cold front approaches our area on Thursday.
For the following weekend, we may be affected by the remnants of typhoon Lan, currently threatening parts of Japan this weekend. Hurricanes form in the Atlantic and eastern Pacific, while typhoons are their counterpart in the western Pacific. Because they often spend longer periods of time over warm open waters, they can be even more powerful than hurricanes, with the strongest becoming super-typhoons.
Typhoon Lan, which may fall into the super-typhoon category, is forecast to be absorbed by the Pacific jet stream after the weekend and might impact our weather next weekend. Of course, to get the next weekend forecast right for our area, the typhoon needs be accurately forecast for Japan this weekend, which is a tall order. If current model forecasts are to be believed, much cooler and unsettled weather might end this month and start the next one.
Gorgeous work week ahead of another quick moving early weekend storm
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.
Cold Saturday before Indian Summer returns
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.
Quiet weather week ahead
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.
