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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – August 16th, 2018

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

Forecast Discussion:

Things were much quieter on Wednesday as compared to Tuesday (when we had our "salad shooter" storm - with what it did to trees and leaves across town).  We had a ribbon of dry air (Figure 1) and a cool front kill most thunderstorm chances.

For today, we have a rather healthy ridge overhead with short waves rippling along to the east and west of us (Figure 2). We reached a high of 91F Wednesday and should see about 90F today.

Another cool front is poised to stabilize the lower atmosphere for tomorrow.  Southern Colorado will see more storms that we do (Figure 3).

Unfortunately, the flood gates of smoke are opening and it should be pretty thick around here today and tomorrow (Figure 4). The atmospheric flow will be right to tap that deeper smoke.

Figure 1: the water vapor satellite image from Wednesday PM. Reds/Oranges are dry air, greys/whites are moist air regions.

Figure 2: The 500mb forecast upper air analysis for Friday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

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

Figure 4: The HRRR (high resolution rapid refresh) model forecast of smoke at all levels for Thursday noon.

The longer range forecast:

A stronger trough approaches for the weekend.  We cool down and have a chance of some good, possibly severe, thunderstorms again (Figure 5).  More on that as the weekend gets closer.

Figure 5: The 500mb forecast upper air analysis for Sunday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Current Weather

Light rain

Light rain

50°F

UV Index
0 Low
Pressure
29.65 Steady
Visibility
7 miles
Dewpoint
44 °F
Humidity
80%
Wind
SSW 2.2 mph
Gust
6.1 mph
Wind Chill
50 °F

Hourly Forecast

Today
4 AM
50°F
Showers
Today
5 AM
51°F
Cloudy
Today
6 AM
51°F
Cloudy
Today
7 AM
52°F
Cloudy
Today
8 AM
55°F
Cloudy
Today
9 AM
60°F
Cloudy
Today
10 AM
62°F
Thunderstorms
Today
11 AM
65°F
Cloudy
Today
12 PM
68°F
Cloudy
Today
1 PM
67°F
Thunderstorms
Today
2 PM
70°F
Mostly cloudy
Today
3 PM
68°F
Mostly cloudy

7 Day Forecast

Mostly cloudy w/ showers

Thursday

72 °F

Turning cloudy, warm; an afternoon shower or two


Thunderstorms

Thursday Night

49 °F

Considerable cloudiness and mild; a thunderstorm in parts of the area in the evening followed by a brief shower or two late


Thunderstorms

Friday

70 °F

Mostly cloudy with a couple of thundershowers


Thunderstorms

Friday Night

45 °F

Cloudy with a couple of thundershowers


Rain

Saturday

48 °F

Chilly with periods of rain and a thunderstorm


Rain and snow

Saturday Night

39 °F

Cloudy with rain, mixed with a little snow late


Mostly cloudy

Sunday

59 °F

Mostly cloudy and warmer


Partly cloudy

Sunday Night

36 °F

Partly cloudy


Partly sunny

Monday

71 °F

Partly sunny, pleasant and warmer


Partly cloudy

Monday Night

45 °F

Partly cloudy


Sunrise and Sunset

Sunrise
6:07 AM
Sunset
7:50 PM

Based on AccuWeather data