Well, it’s about that time. The unofficial start to the summer season. Typically, Memorial Day, in the weather-world, signifies the end of Meteorological Spring and the beginning of Meteorological Summer (Which begins on June 1). This summer will arguably be much different than any other summer we’ve experienced due to a global Pandemic. It’s still weird to say.

The past few days have been wild in terms of severe weather, we’ve had multiple tornado reports, multiple large-hail reports and a decent amount of rain in select areas. That hit–or-miss style to the storms is going away though.

So, Memorial Day is here and what do people do on a long holiday weekend? Well, they get outside of course. Please be respectful of the rules and limitations that are in place right now in your local area. However, people will be out and about in all parts of the state and we have everything from strong storms, to strong winds, to snow coming to areas of Colorado this weekend.

First, the Setup

The Upper Level Setup Through Monday

Way up high in the middle of the atmosphere our main wind current is flowing along. This is depicted in the image above. Troughs are associated with cloud cover and cooler temperatures – like a low pressure system (think cold fronts, hurricanes, etc.). Underneath that large scale flow, are smaller details that enhance the effects of the trough (think other/smaller low pressure systems, dry lines, sea breezes, topography, etc). As we head towards Saturday, Sunday and Monday several of these features will come together to give up a not-so-great weather setup.

Break it Down Some More

Essentially, an area of low pressure currently over Wyoming, will intensify in Eastern Colorado and bring the chance for thunderstorms to the area. Some of which could be severe – those are expected more towards the NE Colorado Plains. Then we have a cold front coming in from the north on Saturday evening that is going to bring in colder and wetter air. That is going to be where our moisture comes from through Sunday. We have another bout of northeasterly winds coming Sunday evening resulting in an upslope-type event.

This secondary push of air should result in widespread rain and storms for the Denver Metro through Sunday night and into Monday morning before skies start to clear in the afternoon.

So, where is it Going to Rain?

Along the Eastern Plains. From Fort Collins to Boulder to Denver to Colorado Springs to Pueblo – there is a solid chance as seeing accumulating (> 0.10″ of an inch of rain). The further east on the Plains you go, the less of a chance of rain you’ll have.

Rain Totals through Monday:
Fort Collins – A general consensus among models is for 0.25 – 0.75″ of rain
Denver – Models are slight higher in terms of precip. totals in the Metro – 0.50″ – 1.25″
Colorado Springs – Same here, a decent rain maker coming – 0.50″ – 1.00″
Pueblo – Good news for areas near Pueblo as its looking like 0.25″ – 0.75″ of rain is coming
Grand Junction – the Western Slope will remain rather dry this weekend – less than .10″ expected
Silverthorne – 0.50″ – 1.00″ expected in the North Central mountains below 10,000′
Gunnison – not as much rain expected here but still some cool showers around – 0.10″ – 0.25″

Where to Expect Rain and Snow this Weekend

Snow?! In Late May?

Yupp! A late-season snow is about to hit the Rockies. It really not that uncommon but it does seem a little shocking since we haven’t heard the “s” word in a while. Thanks to colder air coming and moisture, the setup is looking decent for some to have several inches of snow coming. Mind you, this will mainly occur above 10,000 feet but if you’re anywhere between 7,000-9,500 feet, there will likely be a cold rain which is no fun to be in for a camping trip.

Snow Totals through Monday
Loveland/Berthoud/Kenosha Pass – Probably expecting the most snow this weekend – 3-6″
Monarch/Cottonwood/Kebler/Independence Pass – 2-4″
Cameron Pass – 2-6″
Red Mountain/Molas/Slumgullion Pass – < 2″

Mainly, the will be a central and northern mountain storm. Unfortunately for the San Juan mountains, it’s not looking like a drought reliever for them.


Fire Danger this Weekend

Although I’ve been talking about moisture, moisture, moisture – the reality is that not everyone will see great moisture. If there is fire danger in your area, please do not start a camp fire. If one starts, it has the possibility of rapidly going out of control due to the winds that are expected. This is expected through Saturday but in certain areas this will continue through next week. Be considerate

~ Rain or Shine
I’m Andy Stein

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