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Thursday Update: Longmont Weather Forecast: Up and down temperatures; dry for a long time

The Video Forecast for this Week

In Brief:

We warm mid week, cool week's end, warm again as next week starts - but all times remain dry.

Thursday Update:

As an update to the video above, I was correct, the model had been restarted and did not have a 'memory' of the smoke load in the atmosphere at the start of those runs.  There IS a ribbon of smoke entering Colorado from the remaining western fires for the next few days (Figure 1, smoke at all levels and Figure 2, smoke at the surface).

I thought that was odd!!

Figure1u_09232021
Figure 1 update: smoke at all levels Thursday noon from the HRRR and NOAA.
Figure2_09232021
Figure 1 update: smoke at athe surface Thursday noon from the HRRR and NOAA.

End Thursday update.

Wednesday Update:

The forecast is on track with dry 80's, clear skies and little smoke. Enjoy!

End Wednesday update.

Forecast Discussion:

Passing short waves and a wander in the dominant high-pressure ridge out west will make the temperatures waver between the 60s now to the upper 80s at week's start (Figure 1). Our last big trough is departing as of Monday evening(Figure 2). There is plenty of dry air ready to move in as this trough moves on (Figure 3).

Figure1_09202021
Figure 1: the 10 day graphical forecast from weatherunderground.com for Longmont, CO.
 
Figure2_09202021
Figure 2: the 500mb upper air forecast map for Monday noon from the GFS and tropicaltidbits.com
Figure3_09202021
Figure 3: the water vapor satellite image from NOAA from Monday PM. White/purple is moist air, red/brown is very dry air.

The Longer-Range Forecast:

The heat and ridge peak on Sunday in the upper 80s. The ridge will pass right over Colorado again (Figure 4). Over the next 5 (Figure 5) and 10 (Figure 6) days, things just stay nearly totally dry.  This dryness is expected to hold through the start of October. Hopefully, this column will remain interesting the next two weeks!

  • Fall begins Wednesday at 1:20 p.m., September 22nd this year.

  • Programming note:  I plan to take the last week of October off for my first real vacation in almost two years.  Thanks for your patience!
  • Weather 5280 has also begun their First Snowfall Predication contest, if you want to take a stab at it.

 

Figure4_09202021
Figure 4: the 500mb upper air forecast map for Saturday noon from the GFS and tropicaltidbits.com
Figure5_09202021
Figure 5: the 5 day precipitation total from the GFS and weather5280.com
Figure6_09202021
Figure 6: the 10 day precipitation total from the GFS and weather5280.com

 


About the Author: John Ensworth

John Ensworth used to work from Longmont as the PI for the NASA through the IGES (The Institute for Global Environmental Strategies). He now teaches technology, algebra, astronomy, meteorology, film school, and Lego robotics to middle/high school.
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Current Weather

Sunny

Sunny

49°F

UV Index
4 Moderate
Pressure
29.96 Steady
Visibility
8 miles
Dewpoint
26 °F
Humidity
41%
Wind
ENE 1.7 mph
Gust
4.4 mph
Wind Chill
49 °F

Hourly Forecast

Today
11 AM
47°F
Partly sunny
Today
12 PM
51°F
Partly sunny
Today
1 PM
55°F
Partly sunny
Today
2 PM
58°F
Partly sunny
Today
3 PM
61°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

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