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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

Sunny

Sunny

59°F

UV Index
3 Moderate
Pressure
29.74 Rising
Visibility
8 miles
Dewpoint
36 °F
Humidity
43%
Wind
ESE 3.3 mph
Gust
6.5 mph
Wind Chill
59 °F

Hourly Forecast

Today
10 AM
66°F
Mostly sunny
Today
11 AM
69°F
Mostly sunny
Today
12 PM
71°F
Mostly sunny
Today
1 PM
73°F
Mostly sunny
Today
2 PM
72°F
Partly sunny
Today
3 PM
69°F
Partly sunny
Today
4 PM
66°F
Intermittent clouds
Today
5 PM
62°F
Intermittent clouds
Today
6 PM
59°F
Mostly cloudy
Today
7 PM
55°F
Thunderstorms
Today
8 PM
54°F
Cloudy
Today
9 PM
51°F
Cloudy

7 Day Forecast

Partly sunny w/ t-storms

Wednesday

73 °F

Cooler with sunshine giving way to clouds; windy this afternoon with a thunderstorm in the area late; elevated fire risk due to gusty winds and low humidity


Cloudy

Wednesday Night

45 °F

Overcast


Intermittent clouds

Thursday

70 °F

Windy with intervals of clouds and sunshine; pleasant in the afternoon


Mostly cloudy

Thursday Night

44 °F

Overcast in the evening, then partly cloudy late


Intermittent clouds

Friday

73 °F

Beautiful with times of clouds and sun


Mostly cloudy

Friday Night

47 °F

Mostly cloudy


Mostly cloudy

Saturday

71 °F

Mostly cloudy


Intermittent clouds

Saturday Night

45 °F

Clearing


Mostly cloudy w/ showers

Sunday

71 °F

Turning cloudy with a couple of showers in the afternoon


Mostly cloudy w/ t-storms

Sunday Night

44 °F

Showers and thunderstorms in the evening; otherwise, mostly cloudy


Sunrise and Sunset

Sunrise
5:46 AM
Sunset
8:08 PM

Based on AccuWeather data