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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – July 18th, 2018

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

Forecast Discussion:

We had some BIG storms out on the eastern plains and one that fired just before sunset near Lafayette and Broomfield (Figure 1). That one put down some good hail.

The moisture plume that has wetted parts of the state over the last few days is still here Tuesday but will push to the east tomorrow (green and yellow arrows Figure 2).

Figure 3 is the forecast surface map for today - the surface high pressure is settling in.  The SPC has "no" chance of convection over the Front Range and I-25 areas north of Denver. Wow.

Figure 1: 7:30pm Radar Scope Pro app image.

Figure 2: the water vapor satellite image from Tuesday PM. Reds/Oranges are dry air, greys/whites are moist air regions.

Figure 3: The forecast surface map for Wednesday midday. From NCEP.

The longer range forecast:

The upper level map (figure 4) has a big height ridge to our west feeding us heat and dryness. That ridge still rules the roost come Saturday night (Figure 5). (We'll watch for 'some' moisture that will eventually leak into the ridge later in the work week.)

That ridge and the departure of much of the moisture means hot and dry is back. Figure 6 shows temperatures near 100° F for the next 3-5 days. Moisture and cooler weather doesn't return until the end of the weekend. More as the week goes by!

Figure 4: The 500mb upper air analysis for Wednesday AM. Pink dot is Longmont. Red L is a low pressure trough bottom, blue H is a ridge top.

Figure 5: The 500mb upper air analysis for Saturday PM. Pink dot is Longmont. Red L's are low pressure troughs bottom, blue H is a ridge top.

Figure 6: the next 10 days of the graphical forecast for Longmont, CO from weatherunderground.com

Current Weather

Clear

Clear

61°F

UV Index
0 Low
Pressure
29.45 Falling
Visibility
8 miles
Dewpoint
32 °F
Humidity
33%
Wind
S 3.8 mph
Gust
9.1 mph
Wind Chill
61 °F

Hourly Forecast

Today
1 AM
57°F
Intermittent clouds
Today
2 AM
55°F
Mostly cloudy
Today
3 AM
54°F
Cloudy
Today
4 AM
52°F
Cloudy
Today
5 AM
50°F
Cloudy
Today
6 AM
49°F
Cloudy
Today
7 AM
47°F
Cloudy
Today
8 AM
48°F
Cloudy
Today
9 AM
50°F
Cloudy
Today
10 AM
51°F
Cloudy
Today
11 AM
52°F
Cloudy
Today
12 PM
52°F
Cloudy

7 Day Forecast

Intermittent clouds

Sunday

76 °F

Warmer with intervals of clouds and sunshine


Windy

Sunday Night

47 °F

Winds becoming strong; thickening clouds


Windy

Monday

56 °F

Winds gusting past 40 mph; cloudy and cooler


Intermittent clouds

Monday Night

42 °F

Partly cloudy


Partly sunny w/ showers

Tuesday

59 °F

A couple of showers in the morning; otherwise, windy and cool with times of clouds and sun


Partly cloudy

Tuesday Night

32 °F

Partly cloudy


Intermittent clouds

Wednesday

58 °F

Cool with times of clouds and sun


Intermittent clouds

Wednesday Night

38 °F

Partly cloudy


Intermittent clouds

Thursday

56 °F

Breezy and cool with sun and clouds


Intermittent clouds

Thursday Night

39 °F

Partly cloudy


Sunrise and Sunset

Sunrise
5:54 AM
Sunset
8:00 PM

Based on AccuWeather data