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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – December 24, 2018

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

Forecast Discussion:

Snow continues on the western slopes of Colorado as moisture streams across the West, but Longmont remains dry and a bit above average in temperature (Figure 1).  For Monday evening (Figure 2) the western slopes precipitation picks up more as California and other western states get soaked.

For Christmas morning, northwest Colorado keeps getting new snow showers, but nothing is likely to leak over the Rockies and make it to I-25 communities (Figure 3).

Figure 4 shows the actual snow cover as of Sunday PM (Christmas Eve Eve). Over the next 48 hours, through Christmas night (Figure5), Longmont is unlikely to see anything more than a flurry Christmas morning if we are very very lucky (Figure 8).

Figure 1: The current surface map and radar image from Sunday PM.

Figure 2: The forecast surface map for Monday PM. From NCEP.

Figure 3: The forecast surface map for Christmas morning. From NCEP.

Figure 4: Current snow cover as of Sunday PM from the Weather Channel.

Figure 5: Current snow 48 hour snowfall forecast from the Weather Channel.

The longer range forecast:

AFTER Christmas, things really get hopping in a winter-like way. A powerful trough moves in with another on its heels (Figure 6). The GFS paints a large shield of precipitation from Canada to Mexico with lots of activity over our state (but a bit of a hole over Longmont - Figure 7).

The overall picture (Figure 8) shows two periods of storminess after Christmas over the next 10 days.  Temperatures settle down into the 30'sF then 20'sF for highs at the end of the week and recover just a bit next weekend.  Overall, it is going to be a lot colder and we will have many more chances of snow - coatings to measurable amounts - maybe.

Figure 6: The 500mb forecast upper air analysis for Wednesday evening. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Figure 7: The surface forecast for Wednesday evening. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Figure 8: the graphical forecast for the next 10 days forecast for Longmont, CO from weatherunderground.com

Current Weather

Mostly sunny

Mostly sunny

56°F

UV Index
5 Moderate
Pressure
29.93 Falling
Visibility
8 miles
Dewpoint
24 °F
Humidity
29%
Wind
ESE 2.8 mph
Gust
6.3 mph
Wind Chill
56 °F

Hourly Forecast

Today
12 PM
55°F
Partly sunny
Today
1 PM
57°F
Partly sunny
Today
2 PM
60°F
Partly sunny
Today
3 PM
62°F
Partly sunny
Today
4 PM
64°F
Partly sunny
Today
5 PM
63°F
Partly sunny
Today
6 PM
61°F
Partly sunny
Today
7 PM
58°F
Partly sunny
Today
8 PM
55°F
Intermittent clouds
Today
9 PM
51°F
Intermittent clouds
Today
10 PM
48°F
Intermittent clouds
Today
11 PM
45°F
Intermittent clouds

7 Day Forecast

Partly sunny

Thursday

64 °F

More sun than clouds


Intermittent clouds

Thursday Night

34 °F

Partly cloudy


Partly sunny w/ showers

Friday

54 °F

Cooler with times of clouds and sun; a couple of showers late in the afternoon


Showers

Friday Night

32 °F

A couple of showers in the evening; otherwise, cloudy


Mostly cloudy

Saturday

60 °F

Mostly cloudy


Intermittent clouds

Saturday Night

36 °F

Partly cloudy


Intermittent clouds

Sunday

62 °F

Times of sun and clouds


Mostly cloudy

Sunday Night

36 °F

Becoming cloudy


Showers

Monday

48 °F

Cloudy and chilly with occasional rain; windy in the afternoon


Intermittent clouds

Monday Night

29 °F

Windy in the evening; partly cloudy


Sunrise and Sunset

Sunrise
6:50 AM
Sunset
7:22 PM

Based on AccuWeather data