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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 sunny

Mostly sunny

66°F

UV Index
0 Low
Pressure
29.88 Steady
Visibility
8 miles
Dewpoint
43 °F
Humidity
43%
Wind
N 4.1 mph
Gust
8.1 mph
Wind Chill
66 °F

Hourly Forecast

Today
8 PM
63°F
Intermittent clouds
Today
9 PM
60°F
Mostly cloudy
Today
10 PM
57°F
Mostly cloudy
Today
11 PM
55°F
Mostly cloudy
Tomorrow
12 AM
52°F
Intermittent clouds
Tomorrow
1 AM
50°F
Partly cloudy
Tomorrow
2 AM
49°F
Mostly clear
Tomorrow
3 AM
47°F
Mostly clear
Tomorrow
4 AM
45°F
Clear
Tomorrow
5 AM
43°F
Mostly clear
Tomorrow
6 AM
41°F
Mostly clear
Tomorrow
7 AM
44°F
Partly sunny

7 Day Forecast

Mostly sunny

Wednesday

75 °F

Pleasant and warmer with sunshine and patchy clouds


Partly cloudy

Wednesday Night

41 °F

Patchy clouds


Mostly cloudy w/ t-storms

Thursday

75 °F

Turning cloudy, warm; breezy, a thunderstorm around in the afternoon


Thunderstorms

Thursday Night

49 °F

A thunderstorm in spots in the evening; otherwise, considerable cloudiness


Showers

Friday

70 °F

Mostly cloudy with a couple of showers


Thunderstorms

Friday Night

46 °F

Cloudy with showers and thunderstorms


Rain

Saturday

50 °F

Chilly with periods of rain


Rain and snow

Saturday Night

39 °F

Cloudy with rain, mixed with a little snow late


Mostly cloudy

Sunday

59 °F

Mostly cloudy with a stray thundershower in the afternoon


Partly cloudy

Sunday Night

36 °F

Partly cloudy


Sunrise and Sunset

Sunrise
6:08 AM
Sunset
7:49 PM

Based on AccuWeather data