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9am Update:Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – February 11, 2019

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

9am Update:

Weak up slope flow associated with the front and shortwave creating snow in the mountains (again) has formed freezing fog and very light snow along I-25. This looks like it will clear around noon. There are no watches or warnings associated with this weather situation. Just don't slip!

End 9am update.

A very small amount of snow made it to I-25 in Larimer county (not shown) Saturday night, but nothing hit Boulder county. We remain dry today with some warming with a ridge overhead and down-slope flow from the ongoing snow showers on the Western Slopes (Figure 1).

We warm to the 50's for the middle of the week (Figure 2), then start a good cool down (more on that in the longer range forecast). The GFS (Figure 3) has us completely dry through Thursday AM.

The longer range forecast:

By Friday, after some Thursday PM shower chances, the cool down and change begins (Figure 2 and 3). What starts to occur is an overall trough pattern settling into the west with short wave after short wave moving over the state embedded in the northern branch of the jet stream (Figure 4). Thursday night's showers are kicked off by the short wave drawn over western Colorado in Figure 4.

After Saturday - there are daily snow chances with high temperatures only rising to the lower 30's F most days (Figure 2 and 3). The overall trough, with shortwaves, keeps us cool and moist even up to next Tuesday (Figure 5).

Change is coming after Valentines Day. I'll try to add a heart to the graphical forecast when used this week.

Figure 1: The forecast surface map for Monday PM. From NCEP.
Figure 3: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 3: 10 day meteogram from weather5280.com for DIA.
Figure 4: The 500mb forecast upper air analysis for Thursday PM from the GFS and tropicaltidbits.com. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 5: The 500mb forecast upper air analysis for Tuesday early AM from the GFS and tropicaltidbits.com. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Current Weather

Mostly cloudy

Mostly cloudy

51°F

UV Index
1 Low
Pressure
29.67 Rising
Visibility
8 miles
Dewpoint
28 °F
Humidity
41%
Wind
W 8.9 mph
Gust
19.2 mph
Wind Chill
51 °F

Hourly Forecast

Today
7 PM
49°F
Showers
Today
8 PM
49°F
Showers
Today
9 PM
47°F
Partly cloudy
Today
10 PM
45°F
Partly cloudy
Today
11 PM
43°F
Partly cloudy
Tomorrow
12 AM
41°F
Mostly clear
Tomorrow
1 AM
40°F
Mostly clear
Tomorrow
2 AM
39°F
Mostly clear
Tomorrow
3 AM
38°F
Mostly clear
Tomorrow
4 AM
37°F
Mostly clear
Tomorrow
5 AM
36°F
Partly cloudy
Tomorrow
6 AM
35°F
Partly sunny

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

A shower in spots this evening; otherwise, 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


Partly sunny w/ showers

Thursday

56 °F

Times of clouds and sun with a couple of showers; cool


Partly cloudy

Thursday Night

40 °F

Partly cloudy


Mostly cloudy

Friday

63 °F

Mostly cloudy and warmer


Clear

Friday Night

42 °F

Clear


Mostly sunny

Saturday

68 °F

Mostly sunny


Mostly clear

Saturday Night

43 °F

Mainly clear


Sunrise and Sunset

Sunrise
5:52 AM
Sunset
8:02 PM

Based on AccuWeather data