It'll be night and day different around here by this weekend as we go from the sunny warmth to the deep-freeze and there'll be snowfall too...sounds like winter to me.
First, we are likely headed to well below zero temperatures this weekend and early next week. Sure, some of the daytime highs may be record setting for how chilly they are but overall we are not looking at record low temperatures. Maybe I'll start there, a list of existing record cold temperatures for Denver:
January 18th: -19° 1984
January 19th: -20° 1883
January 20th: -18° 1883
January 21st: -15° 1930
I'll be surprised if we hit any of those lows, but I may be surprised less if we come closest to that on January 21st (Tuesday) depending on how much cold air ultimately settles in and if the sky is clear by that point. Right now, probabilities to the 10th percentile favor the coldest night to be that of Monday into Tuesday.
So, when does it get cold and just how cold are we getting? Focusing on Denver first, then I'll share Colorado Springs. For the metro area, you will feel changes throughout Friday afternoon into the evening (based on current timing which can shift a bit).
Notice how those hourly temperature bars don't have much height to them this weekend or Monday... brrrr. But, based on current probabilities the coldest will come by Tuesday morning - if that is how it pans out, perhaps schools will have some thinking to do... idk.
Okay, here are the hourly temperatures for Colorado Springs, similar overall but perhaps colder Tuesday morning than Denver. -20° from 1930 is Tuesday's existing record for the Springs.
Okay, so we've answered the when (likely later Friday the cold moves in and gets settled), and the how cold is somewhere in the ballpark of 5 to 10° below with colder windchills. Now, that's for the two cities. Other areas on the Front Range may be 10 to 20° below zero in those cold-favored pockets.
What about snow? The chances for snow will increase as those temperatures begin to drop Friday. Note a couple of peaks in the chances, one Friday night through Saturday morning and the other later Sunday through Monday morning.
Regarding these two chances of snow, the first has a better chance of accumulating several inches (most probable with this morning's data is within a three to eight inch range, but we shall see) and will be of a different consistency than that which falls in the coldest air into Monday. Get that first round cleared the best you can or you'll create an even slicker situation when the fine-ice-crystally snow falls in that second batch. Based on those temperatures, we won't have melt/recovery until the middle of the week.
Just for now, I'll set this snowfall projection here. It's early yet and let's see how data may shift in the next couple days.
We will be refining the timing if need be and will get you a specific snowfall forecast as we get closer. For now, you have a better idea of when things will hit and how cold we may be relative to historical records.