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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – April 17, 2019

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

Forecast Discussion:

Our front has pushed through around 5 pm and by tomorrow morning is draped just a bit further south of us, but is still in Colorado (Figure 1). This is being powered by a (positively tilted) trough sliding by over the next day and a half. After the front and up to 11 pm Tuesday, rain showers will be very widely scattered (Figure 3- the HRRR). The weatherunderground.com model has a fairly low chance of precipitation through 6 pm Wednesday with temperatures probably too warm for snow (Figure 4).

The GFS give us a bit of rain (nearby) - Figure 5. The small amounts of snow are as close as Lyons and Boulder - but still it isn't much (Figure 6).

The longer range forecast:

From Figure 4, we climb to the mid 70's F at the end of the week before the next trough moves in (Figure 7 - the red line to our west again). It won't be moving quickly and another trough lurks out in the Pacific - so we cool down and have pretty good rain chances Saturday pm through Tuesday and beyond.

Figure 1: The forecast surface map for Wednesday AM from NCEP.
Figure 2: The 500mb forecast upper air analysis for Wednesday morning. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 3: the HRRR precipitation prediction up to 11pm Tuesday from weather5280.com
Figure 4: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 5: the forecast accumulated precipitation map from the GFS and weather5280.com for Colorado, over the next 2 days.
Figure 6: the forecast accumulated snowfall map from the GFS and weather5280.com for Colorado, over the next 2 days.
Figure 7: The 500mb forecast upper air analysis for Saturday evening. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Current Weather

Light snow

Light snow

33°F

UV Index
0 Low
Pressure
30.33 Rising
Visibility
3 miles
Dewpoint
31 °F
Humidity
92%
Wind
NNE 1.6 mph
Gust
3.2 mph
Wind Chill
33 °F

Hourly Forecast

Today
9 PM
34°F
Snow
Today
10 PM
33°F
Cloudy
Today
11 PM
33°F
Snow
Tomorrow
12 AM
33°F
Snow
Tomorrow
1 AM
33°F
Cloudy
Tomorrow
2 AM
33°F
Cloudy
Tomorrow
3 AM
33°F
Cloudy
Tomorrow
4 AM
33°F
Snow
Tomorrow
5 AM
33°F
Snow
Tomorrow
6 AM
33°F
Snow
Tomorrow
7 AM
33°F
Cloudy
Tomorrow
8 AM
33°F
Flurries

7 Day Forecast

Rain and snow

Friday

41 °F

Chilly; rain and snow showers this morning with little or no accumulation followed by rain and drizzle this afternoon


Snow

Friday Night

33 °F

Periods of wet snow, accumulating 1-3 inches; roads could be slippery


Flurries

Saturday

39 °F

A bit of morning snow with little or no accumulation; otherwise, cloudy and cold; storm total snowfall 1-3 inches


Intermittent clouds

Saturday Night

30 °F

A shower in places in the evening; otherwise, partly cloudy


Partly sunny

Sunday

64 °F

Partly sunny and warmer


Mostly clear

Sunday Night

41 °F

Mainly clear


Intermittent clouds

Monday

79 °F

Warmer with a blend of sun and clouds


Partly cloudy

Monday Night

40 °F

Partly cloudy


Mostly cloudy

Tuesday

66 °F

Mostly cloudy and not as warm


Mostly cloudy

Tuesday Night

40 °F

Mostly cloudy


Sunrise and Sunset

Sunrise
6:15 AM
Sunset
7:44 PM

Based on AccuWeather data