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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – September 17, 2019

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

In Brief:

We say goodby to upper 80'sF after Tuesday. A pretty strong cold front slides across Colorado Tuesday afternoon/evening. The western slopes will see rain and thundershowers over the next week, but the eastern Plains won't see much. The higher elevations will pick up a bit of snow over the next 5 days; really up high, and just a bit.

Forecast Discussion:

The pattern change that is bringing in more Fall-like weather is visible as the trough coming in on the West Coast and the low center off the coast of Canada (Figure 1). This first short wave will usher in a cold front that is visible sweeping out of Wyoming later today (Tuesday - Figure 2, and the first blue lie in Figure 4).

The Longer Range Forecast:

Wednesday we drop to lower 80'sF then another cold front Thursday (pushed in by another deep trough - Figure 3) gives us a small chance of showers and another cool down (from mid 80'sF) to first 80F Friday and then another front (another trough - Figure 4) and a cool down to about
75 F temperatures for the weekend (Figure 5).

Just for fun, the higher elevations should see a dusting of snow over the next 5 days (Figure 6). Can coats, sledding, and Christmas presents be far off...?

You can also say goodbye to hurricane Humberto out in the Atlantic, if you wish (Figures 1,2,3,4).

Figure 1: The 500mb forecast upper air analysis for Tuesday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 2: The forecast surface map for Tuesday PM from NCEP.
Figure 3: The 500mb forecast upper air analysis for Thursday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 4: The 500mb forecast upper air analysis for Saturday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 5: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 6: The forecast snow totals for the next 5 days from the GFS and weather5280.com

Current Weather

Mostly cloudy

Mostly cloudy

56°F

UV Index
0 Low
Pressure
30.26 Rising
Visibility
8 miles
Dewpoint
45 °F
Humidity
66%
Wind
NNE 2.3 mph
Gust
4.5 mph
Wind Chill
56 °F

Hourly Forecast

Today
10 PM
54°F
Partly cloudy
Today
11 PM
53°F
Mostly clear
Tomorrow
12 AM
52°F
Mostly clear
Tomorrow
1 AM
51°F
Partly cloudy
Tomorrow
2 AM
50°F
Mostly clear
Tomorrow
3 AM
49°F
Mostly clear
Tomorrow
4 AM
48°F
Mostly clear
Tomorrow
5 AM
48°F
Mostly clear
Tomorrow
6 AM
47°F
Mostly clear
Tomorrow
7 AM
49°F
Mostly sunny
Tomorrow
8 AM
51°F
Mostly sunny
Tomorrow
9 AM
57°F
Mostly sunny

7 Day Forecast

Mostly cloudy w/ t-storms

Wednesday

68 °F

Turning cloudy with thundershowers this afternoon


Partly cloudy

Wednesday Night

47 °F

Clearing


Mostly sunny

Thursday

77 °F

Mostly sunny and pleasant


Clear

Thursday Night

45 °F

Clear


Sunny

Friday

84 °F

Plenty of sunshine


Mostly cloudy

Friday Night

50 °F

Increasing clouds


Partly sunny

Saturday

83 °F

Partly sunny


Mostly clear

Saturday Night

53 °F

Clear to partly cloudy


Partly sunny

Sunday

86 °F

Partial sunshine


Mostly clear

Sunday Night

50 °F

Mainly clear


Sunrise and Sunset

Sunrise
6:43 AM
Sunset
7:06 PM

Based on AccuWeather data