6:20 AM MST, Saturday, February 13, 2021
The coldest surge of this arctic air mass, along with a weak storm system, will move into the Front Range region later today bringing 3-5 inches of snow and the coldest weather of the season (that weak storm won’t be so weak at it moves from the southern Plains to the Northeast later this weekend). The snow for the Front Range region will be mainly from mid-afternoon today through early morning Sunday.
Sunday is looking like the coldest Valentines Day of record. The record low maximum temperatures are 14 in Boulder (1905) and 8 in Denver (1895). The thermometer may struggle just to get into the single digits in either place.
We should be close to the record lows on Sunday morning. Those are -6 in Boulder and -10 in Denver, both from 1903.
Monday morning will probably be the coldest morning under clear skies. The record in Boulder (-12 from 1903) and is within reach, but Denver’s old record (-20 from 1881) is more of a long shot.
Length of time below 32:
In Boulder, January of 1930 saw a 12-day stretch that remained below 32, the longest such stretch. At the current climate station location (since 1990) there have been three 7-day stretches below freezing: December 1990, February 2014, and December 2015. We will reach 7 days on Monday, and although it may be close to 32 on Tuesday or Wednesday, there is a chance that we will extend this stretch below freezing to 9 days. Later in the week it should warm up.