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Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – July 3, 2019

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

In Brief:

The forecast is becoming summer-simple: high temperatures around 90F each day with a greater or lesser chance of afternoon thunderstorms coming off the mountains. Our most stormy afternoons appear to be Tuesday (post day for this column) and Friday- Saturday. We do cool to the lower 80'sF briefly Saturday.

Forecast Discussion:

The dark green outline shows the deeper moisture (as it begins to move out of the state - Figure 1). The lighter green line outlines very dry air to our west. The chance of severe weather is marginal just north of Longmont up through Ft. Collins etc. (not shown).

The Longer Range Forecast:

We spend a few hours in the lower 90sF Wednesday and Thursday before we cool to the mid 80'sF then lower 80'sF Friday and Saturday. Afternoon storm chances are low, but still exist.

The 4th of July Forecast:

I have a red asterisks at about 9pm on the charts Figure 2 and Figure 3. The weatherunderground model has us at ab out 76F at 9pm with a 4% chance of showers and 25% cloud cover that is decreasing. The GFS based 7! Timer model (Figure 3) has us at about 63F with cloudy skies and showers occurring. It begins to clear after midnight. There is some clear disagreement - we'll keep an eye on it!

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 NWS.
Figure 2: the graphical forecast for the next 10 days for Longmont, CO from
Figure 3: The 2.5 day sky conditions forecast from 7! Timer (the GFS).
Figure 4: the forecast accumulated precipitation map from the GFS and for Colorado, up to July 4th morning.
Figure 5: the forecast accumulated precipitation map from the GFS and for Colorado, up to July 4th late night.


Mostly clear

Mostly clear


UV Index
0 Low
30.32 Rising
10 miles
47 °F
WSW 4.6 mph
5.2 mph
Wind Chill
61 °F


Mostly sunny


94 °F

Mostly sunny and very warm; air quality will be unhealthy for sensitive groups

Mostly clear

Saturday Night

60 °F

Mainly clear; air quality will be unhealthy for sensitive groups

Partly sunny w/ t-storms


98 °F

Very warm with partial sunshine; a shower or thunderstorm in spots in the afternoon

Partly cloudy w/ t-storms

Sunday Night

65 °F

A shower or thunderstorm in spots in the evening; otherwise, mainly clear and mild

Partly sunny


96 °F

Remaining very warm with some sun

Mostly clear

Monday Night

58 °F

Mainly clear

Partly sunny


88 °F

Not as hot with sun and some clouds

Partly cloudy w/ t-storms

Tuesday Night

58 °F

A couple of thunderstorms around in the evening; otherwise, patchy clouds

Partly sunny


88 °F

Beautiful with sunshine and some clouds

Mostly clear

Wednesday Night

57 °F

Clear to partly cloudy

Sunrise and Sunset

11:41 AM
2:30 AM

Based on AccuWeather data