A look at the holiday week forecast and beyond (turning colder by end of Dec)

12/18/24 8:45pm: Hi, lets take a look ahead at what we can expect over the busy holiday week and beyond in terms of the overall weather pattern and when they next storm systems may arrive (and cold air). I'm basing my dates on a combination of the GFS-Ensemble (which has better skill > 7 days out) with the GFS deterministic model by looking at 24hr total liquid precip and the 700mb temps/wind (700mb is at about 10,500ft and is a good indicator of the airmass for CO).

• A ridge of high-pressure will bring warm and dry weather to the state from Thu (12/19) through Sun (12/22). Den/Bou could have some record high temps near 65 degs on some of those days. Windy at times over the Front Range mountains/foothills

• First weak storm system expected to impact mountains with some light snow from Mon am to Tue am (12/23 to 12/24): 1-4" of snow for the ski areas

• Next wave expected around Wed pm to Thu pm (12/25 to 12/26) with more snow for the mountains, slight chance for front-range (Den/Bou)

• Then a stronger storm system with colder air likely from around Fri 12/27 to Sun 12/29...its a ways out but this looks like a more prolonged / substantial snow-storm for the mountains, heavy snow possible

• Den/Bou and the front-range will have best chances for snow also around Sat into Sun (12/28 to 12/29) but uncertainty is high, turning much colder

• The pattern remains active at end of Dec with another storm slated for around Mon 12/30 through Tue 12/31...and could be the coldest air of the season with snow for both the mountains and front-range...but that is way out there so who the heck knows lol

• Bottom line is likely turning much more active and colder as we get into the end of Dec (prior to this very warm). But maybe the bigtime snow will hold off until we get back from Costa Rica 🙂

First image loop shows forecast 24hr total precip over the next 12 days from latest GFS, take amounts/details with grain of salt but you can see the overall storm pattern. Second image is equivalent but for 700mb temps/wind and you can see the ridge initially followed by chances for much colder air in 10 days (Mon 12/30 in the image). Third image (Or first if FB is still being weird) shows 24h precip ending Fri pm 12/27 form latest GFS-Ensemble-Avg (GEFS) showing strong signals for the 12/27-12/29 time period)