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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – January 13-15, 2020

This content was originally published by the Longmont Observer and is licensed under a Creative Commons license.

In Brief:

Hold on, I'm looking something up... tedious, dull, monotonous, repetitious, unvaried, dry... OK those were synonyms for boring. Except for a slight chill and a couple of dry cold fronts, Longmont will see very little variation in the weather for the next week or more. That just means that exciting winter weather is building up for a big hit later this season! (I hope.)

Forecast Discussion:

Snow continues in the mountains with most to all ski resorts getting a daily addition of fresh powder (Figure 1). We'll see warming down-slope flow here with some gusty windy conditions this afternoon (Monday). The upper air pattern this week is very "zonal" or flowing west to east. There is a gentle troughniess in the West with small short waves embedded in the flow. These troughs aren't deep enough or slow enough to pull in moisture east of the Rockies (Figure 2). We remain dry.

The Longer Range Forecast:

We will see about 5-8 degrees of cool down from a dry cool front Wednesday afternoon and again Friday afternoon (Figure 3). The rest of the time we'll rise to about 50F each afternoon. Those fronts do mean that the mountains will see a bit more enhanced snow fall rates (good for them!).

The first front is approaching Tuesday night (Figure 4). The upper air pattern rebounds to a shallow ridge heading into Thursday (Figure 5) - allowing us to quickly warm again to 50F (watch for down slop winds every 'warm' day). Over the next 10 days the mountains see a foot to a foot and a half in the higher mountains, but no snow occurs down on the Plains (Figure 6).

Figure 1: The forecast surface map for Monday noon from NCEP.
Figure 2: The 500mb forecast upper air analysis for early Monday PM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 3: the graphical forecast for the next 10 days for Longmont, CO from
Figure 4: The forecast surface map for Tuesday night from NCEP.
Figure 5: The 500mb forecast upper air analysis for early Wednesday PM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 6: 10:1 (snow to liquid) snowfall totals through the next 10 days from the GFS and tropicaltidbitscom for Colorado made Monday morning.


Mostly cloudy

Mostly cloudy


UV Index
0 Low
30.07 Steady
10 miles
45 °F
N 0 mph
5.5 mph
Wind Chill
64 °F


Partly sunny w/ t-storms


89 °F

Very warm with sun followed by some clouds; a shower or thunderstorm in spots late this afternoon

Partly cloudy w/ t-storms

Tuesday Night

57 °F

A shower or thunderstorm in spots early this evening; otherwise, partly cloudy and mild

Partly sunny w/ t-storms


89 °F

Periods of clouds and sunshine with a shower or thunderstorm in spots late in the afternoon

Partly cloudy

Wednesday Night

55 °F

Partly cloudy

Partly sunny


90 °F

Very warm with sun and some clouds

Mostly clear

Thursday Night

55 °F

Clear to partly cloudy

Mostly cloudy


89 °F

Rather cloudy and very warm; breezy in the afternoon

Mostly cloudy

Friday Night

60 °F

Mostly cloudy and mild

Partly sunny


91 °F

Breezy in the morning; otherwise, partly sunny and very warm

Partly cloudy

Saturday Night

53 °F

Breezy in the evening; otherwise, partly cloudy

Sunrise and Sunset

11:32 AM
2:25 AM

Based on AccuWeather data