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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – September 15th, 2018

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

Forecast Discussion:

The heat goes on!  (How many more of these catchy phrases can I come up with?)

Figure 1 shows that with the upper air ridge (shown for many days now) and the surface high (shown for as many days) still in place, we warm up to record levels again this afternoon.  Temperatures are 10 to 15 degrees above normal for today (82F).

We again have no chance of convection/thunderstorms today (Figure 2). It will be just dry, clear, and smoky at times. Figure 3 shows the smoke from local Colorado fires getting pulled back around to this side of the Rockies at times.  I saw some of it up in the distance north at sunset Friday PM.

Figure 1: the departure from normal temperature afternoon Saturday- surface temperatures from weather5280.com

Figure 5: the day 2 SPC thunderstorm and severe weather forecast made Friday (valid Saturday).

Figure 3: The HRRR (high resolution rapid refresh) model forecast of smoke at all levels for Saturday PM.

The longer range forecast:

We stay hot, dry, and smoky at times through Monday.  Then the winds of change approach as the western trough begins to make inroads towards us.  There might be some tropical moisture entrained into the flow as well from the eastern Pacific. Figure 4 is the GFS meteogram out 10 days.  Tuesday on into Wednesday, temperatures drop to below normal and 'some' rain chances return (scattered rain chances, at least).

Figure 4: the GFS temperature and ensemble precipitation meteogram forecast for the next 10 days from weather5280.com

Current Weather

Mostly cloudy

Mostly cloudy

59°F

UV Index
6 High
Pressure
29.88 Falling
Visibility
8 miles
Dewpoint
25 °F
Humidity
27%
Wind
SE 3.2 mph
Gust
9.6 mph
Wind Chill
59 °F

Hourly Forecast

Today
2 PM
61°F
Partly sunny
Today
3 PM
63°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
Tomorrow
12 AM
44°F
Intermittent clouds
Tomorrow
1 AM
42°F
Intermittent clouds

7 Day Forecast

Partly sunny

Thursday

64 °F

Partly sunny


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