Latest on the active weather pattern and some much colder air coming next week

01/02/24 7:35pm: Hi, hope you are having a good Thu evening. Well after a brief break (and nice warm up) tomorrow we have an active weather pattern shaping up through next week with some much colder air slated to come into CO starting Sunday. Here are some things I'm seeing:

First a very nice Friday coming up across the state as a short-wave ridge moves through. Warm in Den/Bou with temps in the upper 50s, will be nice in the mountains as well with less wind.

Snow starts to move back into the mountains Sat am and it will start turning windy again. Sat will start out nice on the front-range before changing in the aftrenoon.

For the north-central mountains (including Routt, Pitkin, Eagle, Summit, Grand, Clear Creek, western Boulder/Larimer counties): rounds of on/off snow from 11am Sat through 5pm Mon:

First wave 11am Sat to 5pm Sun then more light snow Sun night into Mon (through 5pm Mon): 6-12” of additional snow for the local ski areas, favoring areas west of Vail Pass and along/north of I-70 (Park Range, Medicine Bow Range and locally likely the Tenmile range, why not lol). A bit more snow Tue, but that will favor the Front Range mountains east of the Divide

For Den/Bou, foothills, Palmer Divide and the front-range urban corridor, the first chance for snow will come from 5pm Sat to 5am Sun. but its all going to depend on how far south the short-wave tracks and where the main surface low sets up on Sat night…

As of now not looking great as many of the models show the storm tracking north and the front-range getting strong westerly downslope winds (which kills the precip), with most of the snow setting up east of I-25 onto parts of the eastern plains.

GFS has the low just a bit farther south and hence shows some accumulating snow for Denver to DIA (but mostly east of I-25). I think all of the Den/Bou metro area will sees some flakes fly Sat night but won’t be much: Trace-3” in spots (best chances east of I-25) and also near/along the Palmer Divide. Parts of the eastern plains, say from areas near Ft. Morgan to Limon may get 3-8" of snow.

As the Sat/Sun wave exits the state it will usher in some much colder air, especially for the eastern plains including Den/Bou with high temps falling into the 20s for Sun into Mon (for the metro area)….

Then likely best chance for snow in Den/Bou will come with a reinforcing shot of arctic air expected to arrive Tue morning (likely before sunrise) and this will usher in a cold upslope event for parts of the front-range (Den/Bou and the foothills extending down towards Springs and Pueblo), with best chances from 8am Tue to 2am Wed….it will be much, much colder Tue and Wed: high temps likely only in the teens For Denver (maybe single digits, especially eastern plains).

The Tue/Wed storm system will have little impact on the mountains: some snow for the Front Range mountains along/east of the Cont. Divide: 1-4” in spots. Further west (most of the ski areas): Trace-3” more by Wed. But it will be turning very cold in the mountains by Wed am: low temps in the -20 to -30 degF range by next Wed am so heads up there.

More snow and cold possible for the front-range and northern mountains next Thu/Fri as well (01/09-01/10) but details are highly uncertain. One thing that is clear: it is going to be cold next week Tue through Fri, winter is here lol.

First image loop shows the evolution of the pattern via forecast precip-type/rate, thickness and mslp from GFS (if FB is still being weird it will show up last). Image 2-4 compare forecast total snowfall from now through 5am Mon from latest ECMWF, GFS, and GDPS (GEM: regional view)....take amounts with grain of salt which are mostly for the Sat through Sun night storm (does not include the Tue/Wed upslope for the front-range, that is too far out for details at the moment).