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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – January 1-3, 2020

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

In Brief:

We have a strong jet stream flow from the northwest most of the next 10 days. This means periods of warm down slope winds (especially for this weekend) and quite dry conditions. The mountains will keep getting periods of snow when moisture blobs travel in on that river of air flow aloft.

Forecast Discussion:

A flow of northwesterly winds aloft (Figure 2) dominate our weather pattern this week. A few cool fronts will keep temperatures around normal for this time of year (Figure 1). Snow will keep falling in the mountains (I saw it firsthand in Gunnison this week!). The trough that kicked up winds on Wednesday and dropped showers on the Plains is sliding to the east already (Figure 2).

The Longer Range Forecast:

Increased down slope flow will toss Christmas decorations around now and then (pack-em away! - Figure 3). Temperatures remain normal to above normal through the week.

We were watching a system coming in later in the weekend earlier - that is now looking like a non-system for Longmont. Trough-y-ness is passing Sunday and Monday (Figure 4) but it is not deep and quite quick moving. The GFS sees a foot to a foot and a half of snow in the mountains by Monday - but nothing in Longmont (Figure 5). Even the weatherunderground model gives us only a slight chance of precipitation and a slight cool down Sunday into Monday (Figure 3). The GEM (Figure 6) dumps snow on the mountains with nothing on the Plains.

The January outlook and beyond:

NOAA has us very normal temperature-wise (Figure 7) and equally boring as far as precipitation goes (Figure 8) for January 2020. The weather bell forecasters have us quite warm for January as well, but show how very cold and snowy weather may be in store for February-March (no graphic). We'll see!

Figure 1: the current surface analysis map from Wednesday PM and the weatherunderground.com
Figure 2: The 500mb forecast upper air analysis for Thursday AM. 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 weatherunderground.com
Figure 4: The 500mb forecast upper air analysis for Monday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 5: 10:1 (snow to liquid) snowfall totals through Monday noon from the GFS and weather5280com for Colorado made Wednesday afternoon.
Figure 6: 10:1 (snow to liquid) snowfall totals through Monday noon from the GEM and tropicaltidbits.com for Colorado made Wednesday afternoon.
Figure 7: The temperature outlook for January 2020 from NOAA.
Figure 8: The precipitation outlook for January 2020 from NOAA.

Current Weather

Mostly cloudy

Mostly cloudy

49°F

UV Index
0 Low
Pressure
29.99 Steady
Visibility
8 miles
Dewpoint
33 °F
Humidity
54%
Wind
S 1.7 mph
Gust
4 mph
Wind Chill
49 °F

Hourly Forecast

Tomorrow
12 AM
46°F
Mostly cloudy
Tomorrow
1 AM
44°F
Cloudy
Tomorrow
2 AM
42°F
Cloudy
Tomorrow
3 AM
41°F
Cloudy
Tomorrow
4 AM
39°F
Mostly cloudy
Tomorrow
5 AM
38°F
Intermittent clouds
Tomorrow
6 AM
36°F
Partly sunny
Tomorrow
7 AM
35°F
Partly sunny
Tomorrow
8 AM
41°F
Partly sunny
Tomorrow
9 AM
49°F
Partly sunny
Tomorrow
10 AM
58°F
Partly sunny
Tomorrow
11 AM
62°F
Partly sunny

7 Day Forecast

Mostly cloudy

Thursday

65 °F

Becoming cloudy


Mostly cloudy

Thursday Night

35 °F

Mostly cloudy


Partly sunny

Friday

71 °F

Pleasant with partial sunshine


Partly cloudy

Friday Night

38 °F

Partly cloudy


Partly sunny

Saturday

66 °F

Partial sunshine


Mostly clear

Saturday Night

41 °F

Clear to partly cloudy


Mostly cloudy

Sunday

76 °F

Rather cloudy; breezy in the afternoon


Intermittent clouds

Sunday Night

46 °F

Partly cloudy


Cloudy

Monday

60 °F

Cloudy and cooler with a shower in spots; windy in the afternoon


Mostly cloudy

Monday Night

41 °F

Breezy in the evening; otherwise, mostly cloudy


Sunrise and Sunset

Sunrise
5:58 AM
Sunset
7:57 PM

Based on AccuWeather data