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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – July 31, 2019

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

In Brief:

The moisture flow has improved and afternoon storm chances are getting better. We won't see extreme heat for a while, but the air will get noticeably more sticky feeling. A short wave and associated weak front will move through the state Thursday leading to our best chance of measurable rainfall and thunderstorms out of the next week to 10 days.

Forecast Discussion:

The water vapor satellite image shows a dramatic improvement of moisture flow over Colorado from the tropics (see the discussion for Monday for the progression in images - Figure 1). This is because the upper-level high center has shifted almost to the Texas panhandle (Figure 2). I drew the troughs and ridges and height centers on Figure 2 back on Figure 1 so you can see the reflection of air flow patterns in the moisture image.

For today (Wednesday)- we'll see more cloud cover and a bit better chance of a storm than we saw Tuesday (Figure 3).

The Longer Range Forecast:

A trough will cut into the ridge and pass over Colorado Thursday (Figure 4) and will bring a wind shift, surface convergence and an enhanced chance of storms and wider-spread rainfall (Figure 3). Beyond that we hover in the upper 80's F and lower 90's F with daily thunderstorm chances.

Figure 1: the water vapor satellite image (browns/reds are dry air, whites and light grey is moist air, purple/blue is ice and high cloud tops). From the the Weather Channel from Tuesday.
Figure 2: The 500mb forecast upper air analysis for Wednesday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 3: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 4: The 500mb forecast upper air analysis for Thursday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.

Current Weather

Mostly cloudy

Mostly cloudy

50°F

UV Index
0 Low
Pressure
29.57 Steady
Visibility
8 miles
Dewpoint
24 °F
Humidity
37%
Wind
W 5.5 mph
Gust
14.4 mph
Wind Chill
48 °F

Hourly Forecast

Today
9 PM
51°F
Showers
Today
10 PM
49°F
Intermittent clouds
Today
11 PM
49°F
Partly cloudy
Tomorrow
12 AM
48°F
Mostly clear
Tomorrow
1 AM
47°F
Mostly clear
Tomorrow
2 AM
46°F
Mostly clear
Tomorrow
3 AM
44°F
Mostly clear
Tomorrow
4 AM
43°F
Partly cloudy
Tomorrow
5 AM
43°F
Intermittent clouds
Tomorrow
6 AM
42°F
Mostly cloudy
Tomorrow
7 AM
44°F
Cloudy
Tomorrow
8 AM
48°F
Mostly cloudy w/ showers

7 Day Forecast

Showers

Monday

57 °F

A few showers this morning; otherwise, mostly cloudy, breezy and cooler


Intermittent clouds

Monday Night

42 °F

An evening shower in spots; otherwise, partly cloudy and breezy


Partly sunny w/ showers

Tuesday

60 °F

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


Partly cloudy

Tuesday Night

33 °F

Partly cloudy


Intermittent clouds

Wednesday

58 °F

Cool with times of clouds and sun


Mostly cloudy

Wednesday Night

35 °F

Increasing clouds


Partly sunny w/ showers

Thursday

56 °F

Times of clouds and sun with a couple of showers; cool


Cloudy

Thursday Night

43 °F

Cloudy


Mostly cloudy

Friday

62 °F

Mostly cloudy and warmer


Mostly clear

Friday Night

40 °F

Mainly clear


Sunrise and Sunset

Sunrise
5:53 AM
Sunset
8:01 PM

Based on AccuWeather data