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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – March 11, 2019

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

Forecast Discussion:

Mild nice-ness continues today. Mountain snows continue today. Figure 1 shows a minor upper level ripple rolling past Colorado to the south keeping the snow-train blowing in the mountains and on the Western Slopes (and rain in New Mexico). We will just get breezes and clouds in NE Colorado. We warm up, a lot, right before the next storm with southwest winds and down-slope flow on tomorrow/Tuesday (Figure 2).

The longer range forecast:

The big news and the big question this week is concerning the next big storm (animation in Figure 3). Somewhere, not far to the east of us, or up into the foothills and over our town, heavy snow, winds to hurricane force/speed, incredible low pressure, and heavy amounts of rain will fall. This will be a very major winter/spring storm for Colorado, Nebraska, Kansas, Texas, and Oklahoma that some people will talk about for years. But will it be us?

Models like that at weatherunderground.com (Figure 2) have backed off, again, on how much snow we'll get. This run only shows 1-3 inches. The reason Longmont and North Denver to Fort Collins may get skipped is down- slope flow. Really significant down-slope flow. Remember, this flow of air off the mountains compresses the air, warms the air, and suppresses rainfall/snowfall due to the 'drying' that occurs in this process. Figure 4, the GFS, shows this powerful snow-hole along I-25 very clearly with just a coating to 1 inch of snow by Thursday. The GEM (Figure 5) keeps the NE quadrant of the state quite dry and again only gives us 1/2 to 1 inch. Figure 6, the NAM, gives us 4-5 inches, but areas around us 9-12 inches (just a few miles away to the east and west).

If you ARE hoping for a snow day, all hope is not lost. Much can change as we lock down the temperatures and actual eventual path of the low. It is still about 2 1/2 days away.

After that storm we return to normal temperatures and dry conditions. It might start to feel like spring for Spring Breaks all around.

Figure 1: The forecast surface map for Monday PM from NCEP.
Figure 2: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 3: the animation of the Sunday "take" on the mid-week storm from the GFS and weather5280.com
Figure 4: the forecast accumulated snow map from the GFS and weather5280.com for Colorado, through the next 4.25 days.
Figure 5: the forecast accumulated snow map from the GEM and tropicaltidbits.com for Colorado, through the next 4.25 days.
Figure 6: the forecast accumulated snow map from the NAM and tropicaltidbits.com for Colorado, through the next 4.25 days.


Current Weather

Cloudy

Cloudy

70°F

UV Index
1 Low
Pressure
29.6 Steady
Visibility
8 miles
Dewpoint
31 °F
Humidity
23%
Wind
NNE 5.6 mph
Gust
10.8 mph
Wind Chill
70 °F

Hourly Forecast

Today
4 PM
68°F
Intermittent clouds
Today
5 PM
66°F
Mostly cloudy
Today
6 PM
61°F
Thunderstorms
Today
7 PM
58°F
Thunderstorms
Today
8 PM
56°F
Cloudy
Today
9 PM
53°F
Cloudy
Today
10 PM
51°F
Thunderstorms
Today
11 PM
49°F
Thunderstorms
Tomorrow
12 AM
48°F
Cloudy
Tomorrow
1 AM
48°F
Cloudy
Tomorrow
2 AM
47°F
Cloudy
Tomorrow
3 AM
46°F
Rain

7 Day Forecast

Mostly cloudy w/ t-storms

Friday

70 °F

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


Thunderstorms

Friday Night

44 °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

47 °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

43 °F

Partly cloudy


Sunrise and Sunset

Sunrise
6:06 AM
Sunset
7:51 PM

Based on AccuWeather data