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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – June 20, 2018

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

Forecast Discussion:

We had severe weather!  I need to get some hours back into life, so lets look at the numbers and the return to quiet weather - briefly- today.

The front has now pushed down deep to the southern counties of Colorado. Cool stable air has filled in across Colorado. Severe weather is raging across Nebraska and Kansas as the upper air trough passes us and heads east.  We have the added stabilizing factor of sinking air on the western side of the trough that has passed (figure 1).

Before things calmed down, we had many reports of severe weather - tornadoes, large hail and damaging winds. Figure 2 shows the reports to the NWS by Tuesday evening.

There were two tornadoes in the state, one in Weld county and one in Lincoln county.

There were 66 reports of large hail.

And there were 7 reports of damaging wind events.  Wow.

Today, a ridge approaches as the trough departs (blue and red lines respectively, Figure 3).  But with warming temperatures, moisture in place as well as weak up slope flow behind the front, thunderstorms are possible this afternoon- but nothing severe (Figure 4).

Figure 1: The current surface map for Tuesday PM from weatherunderground.com

Figure 2: The SPC storm reports for 6/19 as of 8pm.

Figure 3: The 500mb upper air analysis forecast from the GFS for Wednesday PM. Pink dot is Longmont.

Figure 4: the day 2 SPC thunderstorm and severe weather forecast made Tuesday (valid Wednesday).

The longer range forecast:

We warm from here *almost* to 90F on Friday, then cool a bit on the weekend. There are chances of afternoon thunderstorms almost every day. Sunday is looking more stormy.

Summer begins on Thursday June 21st, 4:07am.

Current Weather

Light snow

Light snow

32°F

UV Index
1 Low
Pressure
30.29 Steady
Visibility
3 miles
Dewpoint
29 °F
Humidity
88%
Wind
ENE 2.8 mph
Gust
5.4 mph
Wind Chill
29 °F

Hourly Forecast

Today
11 AM
37°F
Cloudy
Today
12 PM
38°F
Flurries
Today
1 PM
39°F
Flurries
Today
2 PM
41°F
Showers
Today
3 PM
42°F
Cloudy
Today
4 PM
43°F
Cloudy
Today
5 PM
44°F
Cloudy
Today
6 PM
43°F
Cloudy
Today
7 PM
42°F
Cloudy
Today
8 PM
41°F
Cloudy
Today
9 PM
40°F
Cloudy
Today
10 PM
40°F
Cloudy

7 Day Forecast

Rain and snow

Thursday

44 °F

Cloudy and chilly with a couple of showers of rain or snow


Mostly cloudy

Thursday Night

35 °F

Mostly cloudy


Mostly cloudy w/ showers

Friday

48 °F

Chilly with some sun, then turning cloudy; a little rain in the afternoon


Rain and snow

Friday Night

34 °F

Snow at times, accumulating an inch or two; rain mixed in early


Flurries

Saturday

46 °F

A bit of morning snow with little or no accumulation; otherwise, cloudy and chilly; storm total snowfall an inch or two


Intermittent clouds

Saturday Night

31 °F

Partly cloudy


Partly sunny

Sunday

69 °F

Warmer with partial sunshine


Partly cloudy

Sunday Night

44 °F

Partly cloudy


Intermittent clouds

Monday

77 °F

Pleasantly warm with a blend of sun and clouds


Intermittent clouds

Monday Night

39 °F

Increasing clouds


Sunrise and Sunset

Sunrise
6:17 AM
Sunset
7:43 PM

Based on AccuWeather data