ForecastTwo More Winter Storms on the HorizonThe San Juans are favored for heavy snow from Wednesday to Friday, then the northern mountains from Sunday to Tuesday.
- Next system arrives Wednesday, with the heaviest snow starting in the southern and western ranges that afternoon.
- Snow spreads eastwards by Thursday, and wraps up Friday, though a complex transition between this system and the one immediately behind could introduce additional snowfall to northern Colorado on Saturday.
- Much of Thursday to Friday's snow is banded which means hit or miss totals and periods of heavier snow between longer periods of lighter snow.
- Mostly dry from Saturday to Sunday morning for many mountain ranges, then another system brings snow to the northern mountains into Tuesday.
System #1 (Wednesday to Friday)
Colorado is on the edge of a heat wave into Tuesday as a ridge of high pressure sweeps across the western United States. Change is coming in the form of a closed low which will drop into the Rockies on Wednesday and put Colorado in the jet left exit region, with robust southwest flow delivering heavy snow to the San Juans.
From Wednesday afternoon to Thursday afternoon, the San Juans have a good chance of picking up double digit snow totals. Other western mountain ranges (the Elks, Flat Tops, and Grand Mesa to an extent -- temperatures will be a bit of an issue there) should do fairly decently as well during this initial phase of the storm.
Right now the biggest limiting factor for snow potential across most of Colorado is the lack of available atmospheric moisture, as the closed low will start to entrain a significant amount of dry air as it moves over the Four Corners. The deepest moisture plume will quickly move eastwards through Colorado and be positioned to our east during much of the storm.
From Thursday to Friday, a jet max will be directly overhead which means any pockets of decent moisture will be highly productive as jet streaking results in banded snowfall.
Timings of heavier snow, and the best overall snow totals, will be very hit and miss in Colorado's northern and easternmost mountain ranges. Areas that pick up more bands of snowfall, or sit under heavier bands of snow for longer, will do significantly better than areas that may only a small distance away.
These dynamics will also be more significant than orographic (upslope) induced snowfall, which adds a high degree of randomness to the forecast. For our forecast, we're going with some conservative snow total spreads but are expecting a few areas to bust high.
By Friday morning, the banded snowfall should wrap up and a brief period of northwest flow should bring a couple more inches of snow to the northern mountains through the rest of the day. This is somewhat dependent on the evolution of the system that is immediately behind the first system -- it's possible a shortwave ahead of the second system keeps snow going on Friday and into Saturday morning in the northern mountains.
System #2 (Sunday to Friday)
The second system impacts Colorado on Sunday with northwesterly flow.
This is good news for the northern mountains, but the jet looks to be a little too far north for there to be decent dynamics in the central and southern mountains.
Moisture availability looks pretty solid, and the pattern is fairly stationary which should keep consistent snowfall going in the northern mountains into Tuesday.
If the system were to hit exactly as the current Euro model run is expecting, we'd likely see totals like this if not a bit higher:
That said, we would caution you not to get too enthusiastic as uncertainty is quite high what with an entire system ahead of this one. Ensemble models are not showing decent support for a prolonged, stronger event, so we're hesitant to be too excited until those start coming around.
We see a signal for another storm the weekend of the 12th, which looks to again favor the San Juans.
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