Summary:

• Snow begins late Saturday night or Sunday morning
• Lasts through Tuesday morning
• Biggest accumulations along and north of I-70, 1-2+ feet
• Lower accumulations south of I-70, 6-12 inches
• Another storm likely on Christmas Day
• Best powder days will be Sunday PM, Monday, Tuesday AM, Thursday

Details:

I wrote over 1,000 words about the upcoming storm in yesterday's post, so I'll keep today shorter. Not much as changed with the forecast as I'm still expecting big snow over northern Colorado early next week and then another storm on Christmas Day.

As of Saturday morning, the infrared satellite image shows a long tail of blue and green colors pushing from the Pacific Ocean toward the west coast of the United States. This is the moisture that is going to fuel our snowstorm on Sunday, Monday, and into Tuesday morning.

Infrared satellite image ending at 5am Saturday morning. Source: Weathertap.com

Saturday: Partly cloudy with perhaps a flurry or snow shower in the northern mountains.

Saturday night through Tuesday morning: This is when we'll see waves of heavier snow focused on the mountains from I-70 to the north. Within this period of time, the heaviest snow will likely fall Sunday night through Monday. There could be a lull Monday afternoon as one piece of the storm moves out, but then with colder air and a continued northwest flow on Monday night, orographics (air hitting a mountain and being forced to rise) will kick in as the main driver of snowfall which should keep the accumulations going.

The mountains along and north of I-70 should see the heaviest snow accumulations of 1-2+ feet. The National Weather Service wrote these words describing the potential snowfall in the northern mountains:

...EXPECT HEAVY SNOWFALL WILL NOT BE A PROBLEM WITH HIGH CONFIDENCE THAT MOST OF THE MOUNTAINS IN WESTERN COLORADO WILL BE MEASURING SNOWFALL WITH A YARD STICK BY THE TIME MONDAY EVENING ROLLS AROUND.

That's a nice forecast, eh?

For the mountains south of I-70, accumulations will be lighter, but I still think these areas should see 6-12 inches from the storm with lower amounts in the southern San Juans that don't do as well with northwest flow. The most likely time for heavier snow in the central and southern mountains will be on Monday.

The National Weather Service's snowfall map through Monday night is lookin' awfully good. Even if this is overdone in spots, it's still going to be a fun storm.

Snow forecast through Monday evening. Source: National Weather Service

If you're trying to plan your powder days, I think Sunday afternoon, Monday, and Tuesday morning will be the ticket. Monday might offer free refills during the day, and Tuesday morning could offer the fluffiest snow as temperatures will cool Monday afternoon and Monday evening.

Tuesday afternoon: Drying out with leftover snow showers.

Wednesday: Likely dry, perhaps a few snow showers lingering in northern Colorado.

Thursday and Friday: The models are split, with the (usually) more accurate models (European, British) showing a good storm for all mountains while the (usually) less accurate models (American, Canadian) are backing off the storm. I think most areas will see pretty good snowfall on Christmas, perhaps lasting into Friday for northern Colorado.

So...pretty active week, with powder days likely Sunday afternoon, Monday, Tuesday morning, and Thursday. There might be more snow in the northern mountains next weekend, but it'll be a few days before that forecast comes together.

JOEL GRATZ

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