Skip to content

7:30am Update: Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – July 22, 2019

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

In Brief:

Rain chances and cooler weather behind our weekend front lingers today with our lowest high temperature of the recent summer in just the upper 70's F. The front pulls away and we return to upper 80's F for highs. Monsoon-like moisture returns Wednesday giving us afternoon storm chances again.

7:30am Update:

The Plains have been cooled by air flowing in from Canada, but a few storms may fire in the mountains and approach severe limits as far east as the I-25 corridor. The SPC (Figure 1 update) has painted the area as being under a Marginal Risk - for large hail and high winds. It looks like only a couple or a handful of cells will form that get that strong - most folks won't see severe conditions.

Figure 1 update: The severe storm weather forecast for the U.S. from the Storm Predication Center in Norman, OK. Made Monday for Monday.

End 7:30am Update.

Forecast Discussion:

Our weekend front finally begins to head to the east Monday night (Figure 1) after we see a high today (Monday) only around 78° F (Figure 2). Marginally severe weather might return in the afternoon (but is not currently expected). I'll update here again if that changes. The GFS gives us about 1/2 inch of rain from Sunday afternoon to Monday evening (Figure 3). The wunderground model thinks we'll see only about 1/3rd inch of water.

The Longer Range Forecast:

A big upper high sets up for a while in the southwest/four corners area (Figure 4). Tropical moisture will wrap around it into Colorado suppressing the high temperatures that might have occurred. This moisture will also mean afternoon storm chances return Wednesday - but highs struggle to break 90° F this week.

Figure 1: The forecast surface map for Monday night from NCEP.
Figure 2: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 3: the forecast accumulated precipitation map from the GFS and weather5280.com for Colorado, for the next 2 days.
Figure 4: The 500mb forecast upper air analysis for Tuesday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Current Weather

Partly sunny

Partly sunny

64°F

UV Index
4 Moderate
Pressure
29.82 Falling
Visibility
8 miles
Dewpoint
18 °F
Humidity
17%
Wind
SE 4.8 mph
Gust
11 mph
Wind Chill
64 °F

Hourly Forecast

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
Tomorrow
2 AM
40°F
Intermittent clouds

7 Day Forecast

Partly sunny

Thursday

64 °F

More sun than clouds


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