Much of the week will be chilly with highs in the 30’s and lower 40’s thanks to a persistent cold airmass. A couple of weak weather systems will slide through during the week leading to chances for light snow. Nothing looks significant at this time, but there is some uncertainty. Read on for more details.
Week starts out cold with light snow
As discussed over the weekend, light snow developed across the western portions of the Plains and in the Foothills last evening in response to upslope flow and weak mid-level forcing. Most areas saw 1″ or less of accumulation.
Today’s mid-level pattern is shown below. There exists a broad shortwave from west to east across Nevada, Utah, and Colorado, with an embedded shortwave system in Utah. This weather-maker will slide through this afternoon and evening, resulting in another wave of light snow for the Plains and Foothills. As we saw yesterday, there is limited moisture and forcing. Most areas should a dusting or less of accumulation. The chance of snow will be between the hours of 3PM and 10PM. Temperatures on Monday will remain near freezing at best under the cold airmass and cloud cover.
GFS 500 mb vorticity for Monday afternoon
The Mountains should pick up 1 to 3″ from Monday’s storm.
Slightly warmer Tuesday
On Tuesday, the shortwave system slides east of the area. Weak downslope flow takes over in the lower to middle levels of the atmosphere (below). This will help lead to generally sunny skies and warmer weather with highs approaching the upper 30’s to near 40 degrees.
GFS 700 mb wind speed and height on Tuesday
Quiet midday Wednesday, then chance of snow?
On Wednesday, downslope flow will remain in place for the majority of the day, yet conditions will turn colder in the evening with the passage of a cold front from the northeast. Below shows the 250 mb jet stream pattern for Wednesday. Two jet maxes will be in play across the region: (1) is over Wyoming into Nebraska, with a second (2) over Utah. In addition to the jet stream, a cold front will dive southward Wednesday evening into northeast Colorado. While the models are not showing much at this point, it is possible a slight shift in the jet could interact with the low-level upslope behind the front to lead to a quick hit of banded snowfall Wednesday night. Some models are hinting at this right now for the Colorado-Wyoming border area. At this time, we are just putting the chance in the forecast for the Metro area, so stay tuned.
GFS 250 mb jet stream pattern on Wednesday
A closer look at the front is shown below for 800 mb temperatures midday Wednesday and Wednesday evening. Downslope will produce warmer temperatures likely in the lower to middle 40’s. Then the front passes through (bottom right) with temperatures falling into the 20’s and 30’s overnight. Partly cloudy skies will give way to increasing clouds with a chance of evening snow showers.
GFS 800 mb temperature for Wednesday afternoon (left) and evening (right)
Week ends chilly but nothing extreme…another snow chance?
Behind the front Wednesday night, upslope flow will remain in place for the remainder of the week with temperatures in the 30’s under partly to mostly cloudy skies. On Friday, an area of low pressure will take a southern track and move across northern New Mexico (below), with snow possible across southwestern Colorado. As it stands now, the system will be too far south for snow in our neck of the woods. But we are holding out hope it may move slightly further north in later forecast runs to give us a chance of snow…stay tuned once more. Otherwise, expect a chilly end to the week with a fair amount of cloud cover.
GFS precipitation type on Friday
Forecast Specifics:
Monday: Mostly cloudy with light snow showers developing in the mid to late afternoon and continuing into the evening. Most areas will see only a dusting or less of accumulation. Highs in the lower 30’s on the Plains and lower 20’s in the Foothills.
Tuesday: Mostly sunny and warmer. Highs in the upper 30’s on the Plains and in the upper 20’s in the Foothills.
Wednesday: Partly cloudy skies giving way to increasing clouds with a slight chance of evening snow showers or flurries, primarily north of Boulder. No accumulation is expected. Early afternoon highs will reach into the lower to middle 40’s on the Plains and lower 30’s in the Foothills. By late afternoon or early evening, though, a strong cold front will move through with temperatures falling thereafter into the 20’s.
Thursday: Partly sunny with highs in the lower 30’s on the Plains and lower 20’s in the Foothills.
Friday: Mostly cloudy with a small chance of snow showers, mainly south of Denver. Highs in the upper 30’s on the Plains and middle 20’s in the Foothills.
High Country: Light snow showers will develop during the day Monday with 1-3″ of snow for some of the ski resorts. Dry conditions will prevail Tuesday. A chance of snow returns on Wednesday, but is more uncertain and will be minimal regardless. Thursday and Friday will see a chance of snow over western and southwestern parts of the state, with the best powder this week in the San Juans. Though we’re several days out, models are indicating the potential for more than a foot of snow for some ski resorts. Check PowderCAST for forecasts for all the Colorado ski resorts.
DISCLAIMER: This weekly outlook forecast was created Monday morning and covers the entire upcoming week. Accuracy will decrease as the week progresses as this post is NOT updated. To receive daily updated forecasts, subscribe to BoulderCAST Premium.
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