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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – January 20, 2019

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

Forecast Discussion:

Something broke with my editing tools, so I could not update the post for Saturday to include snowfall reports and eclipse forecasts (as promised), so these graphics will start out our discussion today.  Figure 1 update shows Longmont received just about 1/2 inch of snow (that melted pretty quickly).  Boulder received 1/2 to 2 inches of snow in places. Figure 2 update shows we received about 1/5th inch of water while Boulder and areas closer to Denver received 1/4th to 1/3rd inch of water.  Every drop helps!

For the eclipse tonight (Sunday) -the model in Figure 3 update shows mostly clear skies (maybe a touch of haze/high clouds) during the eclipse.  A great forecast. Figure 4 update, from 7Timer's model (the GFS) we have a bit more difficulty from clouds, but the moon can make it through clouds pretty well (until totality).  Figure 2 shows nearly clear skies at the start of the eclipse, but getting worse as the night goes on (weatherunderground's model).

Please see my earlier invitation and eclipse timing post if you wish to come to the Cherrywood Observatory and look through some telescopes and get a tour of the night sky - clouds and bright moon permitting.

Now to the next snow storm.  We have a big system to our distant northwest and our past storm is off pounding the southeastern states.  This gives a chance at a nice eclipse viewing (Figure 1) and a quiet day Sunday.  Figure 2 shows that we wake to clear skies Monday, but things cloud up rapidly and a brief, but strong, period of precipitation moves in after sunset Monday PM into early Tuesday AM (Figure 2).

The GFS (Figure 3) gives us about 3-4 inches of snow (while weatherunderground gave us only about 1 inch - Figure 2).  The NAM gives us about 1-3 inches on the Monday - Tuesday storm.  This 'could' be a more substantial hit this time!

The longer range forecast:

Back to Figure 2, things get colder Tuesday through Saturday with highs mainly in the 30's and 40'sF.  Major cold air will be pouring out of Canada east of our state. We only get a taste of it now and then - with small chances of snow/rain now and then. We'll cover the details more later!

Figure 1 update: new Snow totals for Friday for Boulder county from CoCoRaHS.

Figure 2 update: new Snow totals for Friday for Boulder county from CoCoRaHS.

Figure 3 update: Clear Sky Chart forecast for sky conditions for the next 2.5 days for Longmont.

Figure 4 update: 7Timer (GFS) forecast for sky conditions for the next 3 days for Longmont.

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

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

Figure 3: The forecast accumulated snow map from the GFS and weather5280.com for Colorado, through Tuesday night.

Figure 3: The forecast accumulated snow map from the NAM and tropicaltidbits.com for Colorado, through Tuesday night.

Current Weather

Partly cloudy

Partly cloudy

40°F

UV Index
0 Low
Pressure
29.7 Steady
Visibility
8 miles
Dewpoint
21 °F
Humidity
47%
Wind
W 3.9 mph
Gust
10.1 mph
Wind Chill
37 °F

Hourly Forecast

Today
2 AM
39°F
Mostly clear
Today
3 AM
38°F
Mostly clear
Today
4 AM
37°F
Mostly clear
Today
5 AM
36°F
Partly cloudy
Today
6 AM
35°F
Partly sunny
Today
7 AM
37°F
Intermittent clouds
Today
8 AM
45°F
Intermittent clouds
Today
9 AM
49°F
Intermittent clouds
Today
10 AM
52°F
Intermittent clouds
Today
11 AM
54°F
Intermittent clouds
Today
12 PM
56°F
Intermittent clouds
Today
1 PM
57°F
Intermittent clouds

7 Day Forecast

Partly sunny w/ showers

Tuesday

60 °F

Times of clouds and sun with a couple of brief showers beginning at midday; windy


Partly cloudy

Tuesday Night

35 °F

Partly cloudy and colder; there can be frost in the normally colder spots


Intermittent clouds

Wednesday

58 °F

Cool with times of clouds and sun


Mostly cloudy w/ showers

Wednesday Night

39 °F

Increasing clouds with a shower in spots late


Intermittent clouds

Thursday

54 °F

Cool with times of clouds and sun


Partly cloudy

Thursday Night

43 °F

Partly cloudy


Mostly cloudy

Friday

60 °F

Mostly cloudy


Clear

Friday Night

42 °F

Clear


Mostly sunny

Saturday

68 °F

Mostly sunny


Mostly cloudy w/ t-storms

Saturday Night

43 °F

Mostly cloudy with showers and thunderstorms late


Sunrise and Sunset

Sunrise
5:52 AM
Sunset
8:02 PM

Based on AccuWeather data