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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

Mostly cloudy

Mostly cloudy

62°F

UV Index
1 Low
Pressure
29.64 Rising
Visibility
7 miles
Dewpoint
38 °F
Humidity
40%
Wind
NE 6.1 mph
Gust
11.6 mph
Wind Chill
62 °F

Hourly Forecast

Today
7 PM
60°F
Thunderstorms
Today
8 PM
56°F
Cloudy
Today
9 PM
52°F
Cloudy
Today
10 PM
50°F
Thunderstorms
Today
11 PM
48°F
Thunderstorms
Tomorrow
12 AM
46°F
Cloudy
Tomorrow
1 AM
46°F
Cloudy
Tomorrow
2 AM
45°F
Cloudy
Tomorrow
3 AM
44°F
Rain
Tomorrow
4 AM
44°F
Cloudy
Tomorrow
5 AM
44°F
Rain
Tomorrow
6 AM
44°F
Rain

7 Day Forecast

Mostly cloudy w/ t-storms

Friday

69 °F

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


Thunderstorms

Friday Night

41 °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

44 °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

36 °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

61 °F

Mostly cloudy and warmer


Intermittent clouds

Sunday Night

36 °F

A thunderstorm in spots in the evening; otherwise, 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

Pleasant with sunshine and patchy clouds


Partly cloudy

Tuesday Night

40 °F

Partly cloudy


Sunrise and Sunset

Sunrise
6:06 AM
Sunset
7:51 PM

Based on AccuWeather data