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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – December 13, 2018

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

Forecast Discussion:

The front has swept past Longmont and skies are dark. (I'll post this early, since the storm is underway). The current radar image sows western slope snows have begun (Figure 1).

Figure 2 by Wednesday evening, the front is far to the south with western slope snows almost making it down to Lyons! By Thursday a.m. (Figure 3) the front is far far to the south, but mountain snows and 'plains' snows are falling in just about every direction but not here in town. A dusting IS possible.

Figure 4 is a model used by astronomers that predicts snow around 11 p.m. Wednesday.   The HRRR model, before 1 a.m. Thursday, puts 1-4 inches of snow down in the mountains, with snow almost making it down to Boulder, but not quite. Figure 6, the GFS, has snow south of Denver and up in the mountains from this storm, but nothing right in our town.  My dusting to a coating of snow is still possible.

Figure 1: Radar image from just before noon on Wednesday from weatherunderground.com

Figure 2: The forecast surface map for Wednesday night. From NCEP.

Figure 3: The forecast surface map for Thursday a.m. From NCEP.

Figure 4: the next couple of days of astronomical forecasting with precipitation type (11pm snow flurries). From 7! Timer.

Figure 5: The forecast accumulated snow map from the HRRR and weather5280.com for Colorado, through the next 15 hours.

Figure 6: The forecast accumulated snow map from the GFS and weather5280.com for Colorado, through the next 48 hours.

The longer range forecast:

We warm right up to the 50's F and winds die down after Thursday. Very quiet weather will be the rule through Dec 22nd. That is VERY close to Christmas.

Current Weather

Cloudy

Cloudy

38°F

UV Index
0 Low
Pressure
29.91 Falling
Visibility
8 miles
Dewpoint
37 °F
Humidity
95%
Wind
NNW 1.1 mph
Gust
2.2 mph
Wind Chill
38 °F

Hourly Forecast

Today
3 AM
39°F
Rain
Today
4 AM
38°F
Cloudy
Today
5 AM
37°F
Cloudy
Today
6 AM
37°F
Cloudy
Today
7 AM
38°F
Cloudy
Today
8 AM
39°F
Cloudy
Today
9 AM
42°F
Cloudy
Today
10 AM
46°F
Mostly cloudy
Today
11 AM
49°F
Mostly cloudy
Today
12 PM
52°F
Cloudy
Today
1 PM
55°F
Cloudy
Today
2 PM
57°F
Cloudy

7 Day Forecast

Rain and snow

Saturday

43 °F

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


Rain and snow

Saturday Night

37 °F

Cloudy; rain and drizzle in the evening followed by a bit of snow and rain at times late; travel in the foothills and mountains will be slippery due to snow


Thunderstorms

Sunday

61 °F

Mostly cloudy and warmer; a thundershower in spots this afternoon


Partly cloudy w/ t-storms

Sunday Night

37 °F

An evening thunderstorm in parts of the area; otherwise, partly cloudy


Partly sunny

Monday

70 °F

Partly sunny, pleasant and warmer


Intermittent clouds

Monday Night

43 °F

Partly cloudy


Mostly sunny

Tuesday

73 °F

Mostly sunny and pleasant


Mostly cloudy

Tuesday Night

41 °F

Mostly cloudy


Intermittent clouds

Wednesday

65 °F

Times of sun and clouds with a passing shower in the afternoon


Intermittent clouds

Wednesday Night

39 °F

A thundershower in spots in the evening; otherwise, partly cloudy


Sunrise and Sunset

Sunrise
6:04 AM
Sunset
7:52 PM

Based on AccuWeather data