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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – August 8th, 2018

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

Forecast Discussion:

The big storms formed, were far apart (on Tuesday), and dumped serious hail on a few locations. Longmont dodged a big one around 5pm Tuesday (Figure 1).

The atmosphere continues to dry out at most levels (low level moisture kept Tuesday storms alive).  The red and black colors are atmospheric columns are low on moisture content in Figure 2.  The GFS is forecasting little rain over the next 48 hours (Figure 3).  Both this model and the one used Tuesday morning on Channel 7 news had storms up in Nebraska send a gust front back to the Front Range today that initiated a big storm around Fort Collins.  That will be interesting to see if it occurs.

Figure 1: Radar image from iOS app RadarScope Pro posted on Twitter by Matt Makens

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

Figure 3: The total accumulated precipitation between Tuesday PM and Thursday late PM from the GFS and weather5280.com

The longer range forecast:

The 10 day forecast has a chance of a storm Wednesday (our storm from above?) then very little but a few afternoon storms in afternoon by the weekend and beyond. Temperatures change very little and hover in the upper 80's F throughout the forecast period (Figure 4).

As an interesting note, we have four tropical systems between Mexico and Hawaii (Figure 5). As Joe Bastardi from WeatherBell says, you get a "Ridge over Troubled Water."  There has been a big ridge over the southwest for a long time, so this makes sense. What is even more interesting is that the eastern two-most storms (Llena and John) might merge in a few days.  I've seen tropical system dance around one another, but I've not seen two merge (Figure 6).

Figure 4: the next 10 days of the graphical forecast for Longmont, CO from weatherunderground.com

Figure 5: The hurricane lineup Tuesday in the western Pacific. From the National Hurricane Center.

Figure 6: Hurricane John impacted Tropical Storm Ileana on Tuesday, bringing rough surf conditions and heavy rain to the coast of Baja California. Forecast winds speeds. National Hurricane Center.

Current Weather

Drizzle

Drizzle

34°F

UV Index
0 Low
Pressure
30.21 Steady
Visibility
2 miles
Dewpoint
32 °F
Humidity
94%
Wind
NNE 3 mph
Gust
5.3 mph
Wind Chill
32 °F

Hourly Forecast

Today
8 AM
34°F
Cloudy
Today
9 AM
35°F
Showers
Today
10 AM
36°F
Intermittent clouds
Today
11 AM
38°F
Rain and snow
Today
12 PM
40°F
Intermittent clouds
Today
1 PM
41°F
Intermittent clouds
Today
2 PM
42°F
Cloudy
Today
3 PM
43°F
Cloudy
Today
4 PM
41°F
Cloudy
Today
5 PM
40°F
Cloudy
Today
6 PM
39°F
Rain
Today
7 PM
38°F
Rain

7 Day Forecast

Rain and snow

Friday

43 °F

Chilly with some sun, then turning cloudy; a morning rain or snow shower in spots followed by a little rain this afternoon


Rain and snow

Friday Night

32 °F

Periods of snow; rain mixed in early, accumulating 1-3 inches


Flurries

Saturday

40 °F

A bit of morning snow with little or no accumulation; otherwise, cloudy and chilly; storm total snowfall 1-3 inches


Intermittent clouds

Saturday Night

31 °F

Partly cloudy


Partly sunny

Sunday

64 °F

Partly sunny, pleasant and warmer


Partly cloudy

Sunday Night

41 °F

Partly cloudy


Intermittent clouds

Monday

79 °F

Warmer with a blend of sun and clouds


Partly cloudy

Monday Night

36 °F

Partly cloudy


Intermittent clouds

Tuesday

64 °F

Cooler with periods of clouds and sunshine


Mostly cloudy

Tuesday Night

40 °F

Mostly cloudy


Sunrise and Sunset

Sunrise
6:15 AM
Sunset
7:44 PM

Based on AccuWeather data