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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – August 22st, 2018

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

Forecast Discussion:

The upper level feature bringing some rain and a lot cooler air (and eventually cleaner air) has slowed down a bit. We'll have another cool, cloudy, showery day today.

Figure 1 shows the ample moisture flowing up into the state (green arrow here and in following graphics). That flow is pushing the thickest smoke up into Montana, the Dakotas, and Nebraska (Figure 2).

Figure 3 is the midday surface map for today. A front has passed and pushed down into Arizona and New Mexico. A low sits in the Oklahoma and Texas panhandle and will pump surface moisture uphill into Colorado. That slower trough has opened (is no longer cut off/closed) but is still to our west by this evening (Figure 4).

For this evening, the next forecast surface map has much of the state sitting under a good chance of rain (Figure 5). Rainfall totals for the next 48 hours (Figure 6) paint us in the 1/4th to 1/2 inch area. Wet, but not flooding except under the rare heavy thunderstorm.

Figure 1: the water vapor satellite image from Tuesday PM. Reds/Oranges are dry air, greys/whites are moist air regions. Green arrow is approx. moisture flow.

Figure 2: The HRRR (high resolution rapid refresh) model forecast of smoke at all levels for Wednesday noon.

Figure 3: The forecast surface map for Wednesday noon. From NCEP.

Figure 4: The 500mb forecast upper air analysis for Wednesday PM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Figure 5: The forecast surface map for Wednesday PM. From NCEP.

Figure 6: The total accumulated precipitation predicted between Tuesday PM and Thursday noon from the GFS and weather5280.com

The longer range forecast:

There is still some moisture around Thursday a.m. but things are drying out and warming. We still get to around 90° F for the end of the week and weekend. And there is still a hint of another period of cool storminess early next week. See you here tomorrow!

Current Weather

Mostly sunny

Mostly sunny

55°F

UV Index
8 Very High
Pressure
29.5 Falling
Visibility
8 miles
Dewpoint
24 °F
Humidity
29%
Wind
W 11.7 mph
Gust
28.3 mph
Wind Chill
55 °F

Hourly Forecast

Today
3 PM
55°F
Showers
Today
4 PM
55°F
Cloudy
Today
5 PM
55°F
Cloudy
Today
6 PM
55°F
Cloudy
Today
7 PM
55°F
Cloudy
Today
8 PM
53°F
Mostly cloudy
Today
9 PM
51°F
Intermittent clouds
Today
10 PM
49°F
Intermittent clouds
Today
11 PM
48°F
Partly cloudy
Tomorrow
12 AM
47°F
Mostly clear
Tomorrow
1 AM
47°F
Mostly clear
Tomorrow
2 AM
45°F
Mostly clear

7 Day Forecast

Showers

Monday

57 °F

Winds becoming strong; mostly cloudy and cooler with brief showers this morning followed by a shower in spots this afternoon


Intermittent clouds

Monday Night

41 °F

Partly cloudy


Partly sunny w/ showers

Tuesday

58 °F

A couple of showers in the morning; otherwise, windy and cool with times of clouds and sun


Partly cloudy

Tuesday Night

33 °F

Partly cloudy


Intermittent clouds

Wednesday

60 °F

Times of clouds and sun


Mostly cloudy

Wednesday Night

38 °F

Increasing clouds


Partly sunny w/ showers

Thursday

56 °F

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


Cloudy

Thursday Night

37 °F

Cloudy


Mostly cloudy

Friday

62 °F

Mostly cloudy and warmer


Mostly clear

Friday Night

36 °F

Mainly clear


Sunrise and Sunset

Sunrise
5:53 AM
Sunset
8:01 PM

Based on AccuWeather data