Drastically Colder, Possibly Icy Thursday Atypical Weather Feature Spurs Change

(See bottom of post for cut-to-the-chase forecast)

After record highs in the mid 70s on Tuesday and near record highs in the upper 60s Wednesday, a somewhat rare weather feature, called a "backdoor cold front," moved through the eastern half of Colorado late Wednesday. This feature -- which is so named because it moves from the northeast to southwest instead of from the northwest to southeast (as the vast majority of cold fronts do) -- pushed through the region early Wednesday evening, dropping temperatures more than 35 degrees off their afternoon highs in a matter of hours.

At 12am Thursday morning, as I publish this, we're sitting at 33 degrees with low clouds/fog. Now that the winds aloft are blowing from the northeast to the southwest, some upslope flow will develop over the eastern third of Colorado -- as far west as the foothills of the Rockies. This will initiate the development of light moisture for much of the day Thursday.

While the typical cold front has significant cold air aloft with less at the surface, this backdoor cold front is primarily providing low-level cold air, while the middle levels of the atmosphere remain relatively warm. As a result, the expected precipitation is light freezing rain or freezing drizzle -- not snow.

While there's not a lot of moisture to work with, freezing rain is far more disruptive than snow, so there may be significant travel-related impacts on Thursday. The best chance for slippery conditions are during the first half of the day on typically colder surfaces like bridges, overpasses, secondary roads; I think most major highways should be okay, but it's tough to know. Temperatures will stay nearly steady throughout the entire day -- struggling to get much above the freezing mark, some 35 degrees colder than Wednesday's highs!

FORECAST:

Thursday: Low clouds and dramatically colder with periods of freezing drizzle, freezing fog, and/or light freezing rain. Travel may be dangerous, especially over bridges and overpasses and less traveled roads. Highs will top out in the low to mid 30s. Freezing fog or drizzle may continue Thursday night with colder overnight lows in the mid 20s. Any moisture on surfaces will freeze overnight.

Friday: With temperatures starting off in the 20s, the morning commute could prove dicey, but it's a bit too early to tell. However, sunshine will break out fairly early in the day and we'll see noticeably milder temperatures in the upper 40s -- just about exactly where they should be for this time of year.

Forecast Confidence = 6/10