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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – December 11, 2017

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

Forecast Discussion:

It is shorts and t-shirt weather again (at least for December). The upper air map from last night shows the big west coast ridge that we are on the downhill side of (Figure 1). Note the interesting low under the ridge down in the Pacific ocean off of Mexico and the Baja Peninsula. It is pumping moisture northward (Figure 1 and 2) at the mid- and upper levels.  Nothing for our weather, but it sort of looks like the summer monsoon pattern!

I did check (Figure 3) on the southern California smoke to see if any of that smoke is headed here. For now, that smoke is all going out to sea by the same east to west flow that creates the Santa Anna winds causing the fire problems in the first place. Any smoke you smell or see will be local fields (hopefully planned agricultural burning).

Figure 1: Current 500mb upper air map from Sunday PM.

Figure 2: The current water vapor satellite image from Sunday PM ( white and purple= moist air, reds/brows = dry air).

Figure 3: The HRRR experimental forecast smoke map for all levels of the atmosphere with surface winds.

The longer range forecast:

Figure 4 is the upper air map for next Saturday night when a hint of a trough seems to be possible. This might give us a break from the near continuous near-60F highs of the week. More later!

Figure 4: The 500mb upper air forecast map for Saturday PM next week.

Current Weather

Sunny

Sunny

64°F

UV Index
6 High
Pressure
29.6 Steady
Visibility
7 miles
Dewpoint
33 °F
Humidity
31%
Wind
WNW 5.1 mph
Gust
11.6 mph
Wind Chill
64 °F

Hourly Forecast

Today
11 AM
66°F
Partly sunny
Today
12 PM
67°F
Intermittent clouds
Today
1 PM
68°F
Intermittent clouds
Today
2 PM
69°F
Intermittent clouds
Today
3 PM
70°F
Intermittent clouds
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

7 Day Forecast

Mostly cloudy w/ t-storms

Friday

70 °F

Some sun, then increasing clouds 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