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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – October 21th, 2018

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

Forecast Discussion:

Very nice niceness continues. Figure 1 is the surface map for midday today and high pressure dominates. The dry front to the north will cool temperatures a bit on Monday, but nothing too notable.

Note: I'll be on a big family vacation at the end of the month. There will be no updates to this column for the period October 26-Nov 4. I'll probably create a page of links to my favorite forecast pages in my absence.

Figure 1: The forecast surface map for Sunday noon. From NCEP.

The longer range forecast:

Our approaching trough, though still weak, seems to be grabbing some moisture from the tropics and tropical systems (like Willa) that will increase rain chances. Tuesday into Wednesday looks just a 'bit' more moist now (Figure 2). Don't worry, extreme niceness will return right after that.

The 500mb map for today (Sunday) shows the warm ridge overhead and Willa beginning to send moisture north (Figure 3). Figure 4 is the upper-air pattern Wednesday a.m. with the trough coming in from the west. Willa is closer and more moisture is being temporarily pulled north. The forecast mid-atmospheric moisture map (Figure 5) shows this plume of water that will make cloudy skies and 'some' precipitation fall (though snow levels should remain around 9000 feet).  Enjoy this nice week!

Figure 2: the next 10 days of the graphical forecast for Longmont, CO from weatherunderground.com

Figure 3: The 500mb forecast upper air analysis for Sunday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Figure 4: The 500mb forecast upper air analysis for Wednesday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Figure 5: The mid-atmosphere moisture forecast for early Wednesday AM from tropicaltidbits.com

Current Weather

Partly sunny

Partly sunny

49°F

UV Index
2 Low
Pressure
29.6 Rising
Visibility
8 miles
Dewpoint
45 °F
Humidity
83%
Wind
NW 2.6 mph
Gust
9.1 mph
Wind Chill
49 °F

Hourly Forecast

Today
9 AM
54°F
Cloudy
Today
10 AM
58°F
Cloudy
Today
11 AM
63°F
Cloudy
Today
12 PM
68°F
Cloudy
Today
1 PM
67°F
Mostly cloudy
Today
2 PM
70°F
Mostly cloudy
Today
3 PM
68°F
Mostly cloudy
Today
4 PM
67°F
Mostly cloudy
Today
5 PM
65°F
Cloudy
Today
6 PM
58°F
Thunderstorms
Today
7 PM
56°F
Thunderstorms
Today
8 PM
55°F
Cloudy

7 Day Forecast

Thunderstorms

Friday

70 °F

Mostly cloudy with a couple of thundershowers this afternoon; gusty winds and small hail can accompany any downpour


Thunderstorms

Friday Night

45 °F

Cloudy; a couple of showers and a thunderstorm this evening followed by periods of rain late; gusty winds and small hail can accompany any downpour


Rain

Saturday

48 °F

Chilly with periods of rain and a thunderstorm; travel in the foothills and mountains will be slippery due to snow


Rain and snow

Saturday Night

39 °F

Cloudy with rain, mixed with a little snow late; travel in the foothills and mountains will be slippery due to snow


Mostly cloudy

Sunday

59 °F

Mostly cloudy and warmer


Partly cloudy

Sunday Night

36 °F

Partly cloudy


Partly sunny

Monday

71 °F

Partly sunny, pleasant and warmer


Partly cloudy

Monday Night

45 °F

Partly cloudy


Mostly sunny

Tuesday

73 °F

Mostly sunny, breezy and pleasant


Partly cloudy

Tuesday Night

43 °F

Partly cloudy


Sunrise and Sunset

Sunrise
6:06 AM
Sunset
7:51 PM

Based on AccuWeather data