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.
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.
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.
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.
Thursday, September 1, 2016
A persistent and large Pacific Northwest trough will affect our weather for the next week as it is reinforced by cool air traveling southward from the North Pole. Southwest flow ahead of the trough has picked up a shortwave currently producing showers in northern Arizona, and the short range HRRR model has rain reaching our area before sunrise Friday.
There will be a break in the rain after it ends Friday morning, but the wetter AVN model has another round of afternoon storms as another ill-defined wave moves near the Steamboat Springs area. Curiously, the NAM is dry so that discrepancy lowers forecast confidence.
Though some drier air works into the area on Saturday, there will be enough moisture for another round of afternoon storms, some possibly strong.
By Sunday, much drier air ahead of the advancing trough, forecast to take up residence in the Great Basin for the week, will move overhead and likely produce some spectacularly nice weather for the remainder of the long Labor Day weekend.
Though dry, some cool air from the Great Basin trough will be dragged over our early by Monday by ejecting energy traveling west and then north of our area. The combination of seasonably cool temperatures and a very dry atmosphere will keep morning lows chilly and tender plants in low-lying areas may require some protection.
Cool air continues to pour into the Great Basin trough through the week keeping it quasi-stationary. It appears we will be on the boundary between dry and moist air, with some moisture possibly returning for a brief spell on Tuesday to fuel a slight chance of afternoon storms. Otherwise, seasonably cool temperatures with cool mornings look to persist for the rest of the work week before the Great Basin trough is kicked eastward by another Pacific storm that may threaten next weekend’s weather.