Thursday, September 3, 2020
Temperatures are already near eighty degrees early this sunny Thursday afternoon in Steamboat Springs as we continue to recover from the cool start to the work week. Temperatures are expected to soar toward ninety this dry Labor Day weekend, followed by a dramatic cold front that may bring snow down the the Yampa Valley floor on Tuesday.
A ridge of high pressure currently over the West Coast will move over our area through the Labor Day weekend, with temperatures forecast to soar ten to fifteen degrees above our average of 76 F. But the dry air will keep our cool nights around, and with an average low temperature of 39 F, we could see several more days of fifty degree intra-day, or diurnal, temperature swings.
Enjoy the summery weather because wintry weather is forecast for Tuesday. As in snow, perhaps down to the valley floor! A chunk of cold air currently moving southward from the North Pole will merge with a Pacific system moving over the top of the ridge of high pressure and bring a strong cold front through our area around Monday night. The current timing will be fortuitous for what is expected to be a big travel weekend, as right now it is likely that most travel should be completed by the time the weather excitement begins.
So while we will be ten to fifteen degrees above average ahead of the cold front over the weekend, leading to record to near-record temperatures, we may be twenty to thirty degrees, or more, colder behind it. While it is not that unusual to see fifty degree temperature swings between the high and low of the day, especially in late summer, it is more unusual to see forty to fifty degree temperature swings between days, which we may approach if the storm evolves as current predicted. And I suspect that we may set some sort of two-day record for the largest temperature swings within a day and between consecutive days, though will have to leave that up to the climatologists to document, if such a record even exists.
It does appear, however, that while Labor Day will be dry and mostly sunny with increasing winds from the northwest, we may see the high temperatures dip a bit from the weekend ahead of the front. So we may not see a fifty-fifty degree intra-inter-day swing by Tuesday, but it may be of more of the forty-forty degree variety.
So according to the current forecast timing, we should wake up to quite the change Tuesday morning. At this point, I would guess we’ll see snowflakes in town, and accumulating snow on the mountain by Tuesday night. There is disagreement among the weather forecast models, as expected, with the European ECMWF more consistent in forecasting a wetter system further west than the Amercian GFS. In fact, the ECMWF cuts the storm off from the jet stream and forms an eddy over the Four Corners region (a so-called Four Corners low), and this may keep cool and unsettled weather around through the rest of the work week. The American GFS, on the other hand, ends the storm by midweek with warmer, but still below average, dry weather forecast for the rest of the work week.
My next regularly scheduled weather narrative on Sunday afternoon will be quite interesting, and I’ll certainly have more details on this upcoming mercurial weather event.