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Longmont Weather Forecast 8/20-21/2020

In Brief:

Elevated afternoon storm chances (with smoke) change back to very hot, dry and smoky conditions for the weekend.

Forecast Discussion:

The return of moisture has clouded skies and brought in actual rain to spots (and lightning unfortunately - see Figure 1 in the gallery above). Amounts of rain were very spotty.  This surge of moisture can be seen in the precipitatable water anomaly map in Figure 4.  This is mostly coming from the Pacific ocean this time. The ridge in the west with its close loop of air flow is the biggest feature in U.S. weather right now (Figure 5).  This ridge is so large that it has smaller ridges poking off of it. This keeps smoke circling the entire western U.S. allowing the smoke to build and build (Figure 2 and Figure 3). Yuck.

Some of this moisture (and future moisture) will be sucked into the ridge from Genevieve as it dies moving to the northwest (Figure 6).

We do have a Marginal Risk of severe weather for most of eastern Colorado Thursday (not shown in a map) - the primary risk is for strong gusty thunderstorm winds (not good for the fire conditions).

The Longer Range Forecast:

The moisture gets cut off for a bit over the weekend (brown shading over the state in Figure 7). You can see Genevieve dying and spreading atmospheric moisture out of its center in the lower left of that figure.  Over the next 5 days, precipitation will still be very light and confined mostly east of the Rockies (Figure 9). Most of those rain totals come from Wednesday, Thursday and next Monday (when some moisture returns again).  High temperatures will remain pegged in the upper 90'sF for a while.  We should set the record for the 2nd largest number of 90F+ high temperatures in a calendar year by Saturday afternoon.

Better moisture returns middle of next week (Figure 10). We will see storm chances begin to increase again.

Looking even FURTHER out, amazing amounts of moisture flood into the West (from the death of the next tropical system's death by September 1/2 (Figure 11) followed by a brief sharp cool down on September 3/4 (Figure 12).  Some relief IS in sight!

The Video Weather Forecast this week


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

Mostly cloudy

Mostly cloudy

88°F

UV Index
5 Moderate
Pressure
30.04 Steady
Visibility
13 miles
Dewpoint
44 °F
Humidity
22%
Wind
N 7.7 mph
Gust
15.8 mph
Wind Chill
88 °F

Hourly Forecast

Today
4 PM
87°F
Cloudy
Today
5 PM
88°F
Cloudy
Today
6 PM
89°F
Cloudy
Today
7 PM
89°F
Mostly cloudy
Today
8 PM
85°F
Partly sunny
Today
9 PM
80°F
Mostly clear
Today
10 PM
76°F
Mostly clear
Today
11 PM
72°F
Mostly clear
Tomorrow
12 AM
70°F
Mostly clear
Tomorrow
1 AM
68°F
Mostly clear
Tomorrow
2 AM
66°F
Mostly clear
Tomorrow
3 AM
65°F
Mostly clear

7 Day Forecast

Intermittent clouds

Tuesday

94 °F

Very warm with intervals of clouds and sunshine


Partly cloudy

Tuesday Night

61 °F

Partly cloudy


Partly sunny w/ t-storms

Wednesday

81 °F

Times of sun and clouds with a thunderstorm in the afternoon; thunderstorms can bring hail and damaging winds


Partly cloudy w/ t-storms

Wednesday Night

60 °F

An evening thunderstorm; otherwise, partly cloudy


Thunderstorms

Thursday

88 °F

Mostly cloudy with a thunderstorm in spots in the afternoon


Partly cloudy

Thursday Night

58 °F

Partly cloudy


Mostly cloudy

Friday

91 °F

Variable cloudiness


Mostly clear

Friday Night

61 °F

Clear to partly cloudy


Partly sunny

Saturday

88 °F

Partly sunny with a thunderstorm in spots in the afternoon


Clear

Saturday Night

60 °F

Clear


Sunrise and Sunset

Sunrise
5:44 AM
Sunset
8:29 PM

Based on AccuWeather data