Beautiful week followed by cold and unsettled weekend
Sunday, September 18, 2016
Enjoy the current spectacular weather since a big change is forecast starting around late Thursday or Friday.
In the meantime, sunny warm days and cool nights will persist for Monday and Tuesday as a flat ridge keeps the dry air around. Meanwhile, to our west, some energy left behind by last week’s Great Basin storm is currently spinning off the southern California coast and will be joined by a tropical storm traveling northward from Baja on Tuesday. An incoming Pacific storm from the Gulf of Alaska will mix with additional cold air in Alaska and move southward along the West Coast early in the week, pushing this warm complex across the southwestern US.
Models have struggled with the northward extent of this complex as it mostly passes to our south, but it appears clouds may be the only affect for northern Colorado by Wednesday, similar to way these events developed over the last half of the summer.
Thursday will be a breezy to windy day with southwest winds as the large Pacific storm makes landfall. A wave ejecting from the storm may bring showers to Steamboat Springs as early as Thursday afternoon, though the most noticeable affects will occur when the cold front associated with the parent storm crosses the area later Thursday or Friday.
The exact timing of the front is questionable as the storm elongates to the north and south as energy ejects in both those directions, but models agree that significant cooling accompanied by precipitation will occur for a couple of days, most likely Friday along and behind the front and Saturday when trailing energy keeps showers going in cool, moist and unstable northwest flow. While snow accumulations are a good bet near the top of Mt. Werner, snowflakes could fall to 8000′ or lower by Saturday morning.
Models do have have clearing in continued below normal temperatures by Sunday, though that will be jeopardized if the storm moves slower than currently forecast.
Beautiful late-summer weather on tap for the next week
Friday, September 16, 2016
After a cool and unsettled week, dry, sunny and warm days with cool nights return for most of the next week in Steamboat Springs.
While the storm system responsible for last week’s weather has largely moved east of the area, some energy was left behind and is currently residing in the southwestern US and Baja. There was uncertainty in Monday’s forecast regarding this energy and it’s northward extent when another strong Pacific storm kicks it eastward around midweek. Though there is still disagreement, the bulk of that storm looks to stay south of our area, possibly introducing some clouds but likely allowing the beautiful weather early in the week to persist through most of the work week.
The incoming Pacific storm, however, is far more difficult to predict at this time as a complicated pattern consisting of cool air moving southward from Alaska, several waves of additional Pacific energy, a transient building ridge centered in the northwestern US and British Columbia and even a tropical storm moving northward from Baja interact. Current forecasts have the Pacific jet stream eventually undercutting the transient ridge around the end of the work week, allowing the Pacific storm to move eastward and threaten the week of fine weather around late Thursday and Friday.
Incidentally, this is the first event this fall where Pacific energy undercuts a ridge in the vicinity of the Gulf of Alaska, and reflects the growing dominance of a winter-season jet stream. Over the remainder of the fall season, there will battles between a weakening summer-like ridge over the southwestern US and a strengthening winter-like Pacific jet stream. While summer wins the immediate battle, it’s victories will become more sporadic and shorter lived as cold air continues to build in the northern latitudes.
Breezy and unsettled weather for the work week turns nicer for the weekend
Monday, September 12, 2016
A cutoff low spinning in the western Great Basin will be nudged eastward to northeastward through the work week, continuing the breezy and unsettled weather before drier air is advertised for the weekend.
We will again be susceptible to showers on Tuesday as an ill-defined wave ejects out of the Great Basin low. By Wednesday, the cutoff low begins to move eastward and elongates to our north and south through Thursday, continuing the threat of showers and increasing already breezy winds from the southwest.
The storm finally drags a weak cool front through the area on Thursday, decreasing the winds but again continuing the chance of showers, with some of the storms possibly strong in the vicinity of the front. The cool air may make for a chilly Friday morning, but drier air behind the storm should make for a mostly sunny day.
Some more cool air leaks into the Steamboat Springs area by Saturday morning for another chilly start to the day, but temperatures should warm nicely for a beautiful day as the last bit of the storm moves east of our area.
It looks like another beautiful day for Sunday and possibly Monday before there is model disagreement about a storm to our southwest that may allow for moisture to return to Colorado early in the next work week.
Moisture returns for the next work week
Friday, September 9, 2016
While one trough of low pressure to our north drags a dry cool front through the region today and tonight, another trough crosses the Pacific Northwest coast on Sunday and splits, with the southern portion closing off and taking up residence in the Great Basin for the upcoming work week.
The weekend will be sandwiched between these troughs and feature beautiful warm sunny days and quite cool nights with outdoor plants likely needing help to make it through the around-freezing temperatures on Saturday morning.
The southern portion of the split will force our winds to back from the current northwest to southwest by Sunday night, allowing a tap of subtropical moisture to flow over Colorado. A cool front associated with the passing northern part of the split on Monday will likely enhance showers by the afternoon that may extend into the evening as it swings through the area.
Though the heaviest showers will pass as the northern part of the split moves east of the area on Monday, the lumbering Great Basin low will allow moisture to remain over our area, continuing the chance of afternoon showers through most of the work week.
Beautiful late summer weather on tap for most of the next week
Monday, September 5, 2016
Cool nights and warm mostly sunny days will be the rule through the work week and lasting for most of next weekend. A trough to our west in the Great Basin will remain quasi-stationary for the beginning of this period, occasionally ejecting waves of energy that will drag shallow and dry cool fronts through or just north of the Steamboat Springs area. The strong early September sun will allow temperatures to quickly recover from the cool mornings.
The Great Basin trough will be ejected to our north by a couple of Pacific waves late in work week, with the second wave looking to deepen as it approaches our area late in the weekend. There may be some moisture that is drawn northward in the southwest flow ahead of the storm around Sunday with a well defined cold front currently advertised for Monday. The timing and strength of the front will no doubt change as the models get a better handle on the storm, but at this point the American GFS says it may be cold enough for some snow at the top of Mt. Werner.