Well, after a snow season like the one we just endured…or are enduring…it’s not shocking that we’re talking about a pretty major snowstorm for the Denver metro and the surrounding areas in the second half of May. This late-season storm will produce heavy, wet snow and sub-freezing temperatures both of which could cause major issues around the region.

We first talked about this storm earlier in the week when the potential for a storm seemed to be eclipsed by the fact that we haven’t seen a decent snow since mid-March and the fact that we’ve had above-normal temperatures and more fire danger than we can count since April.

Regardless, a winter storm is coming and it will bring so much beneficial moisture to the Denver metro and surrounding areas which is the best news for our continuing drought concerns. Let’s dive in.

A large storm will move through the northern and central Rockies between now and this weekend. That storm is the culprit for our late-season snow we’re expecting. You’ll first notice through Thursday that we are going to have well above-normal temperatures with windy conditions. High fire danger will precede this snow event as the storm nears. Temperatures in Denver should approach 90-degrees Thursday afternoon. The record for this date is 92-degrees. Keep this in mind as high fire danger is nothing to mess around with as we’ve come to know.

As the system nears, it will drop a strong cold front across the area. This will push through Thursday night dropping temperatures into the low 40s, possibly even the upper 30s, for the Denver area by Friday morning. A solid 45-50 degree temperature drop!

Behind this cold front, we’re talking about a classic upslope snow event for our area. By Friday morning snow will be falling for those above 7,000 feet in elevation. For the lower elevations of the I-25 corridor, a cold rain will encompass the area during the morning with widespread precipitation falling from Ft. Collins to Castle Rock by noon. We will watch a secondary push of colder air and energy move through the metro Friday afternoon and this will aid in dropping snow levels down to 5,000′ or low enough for snow to be falling in downtown Denver.

Everyone will be seeing snow by Friday afternoon into the early evening. Those above 6,500-7,000 feet will be seeing snow for the duration of Friday and overnight into Saturday morning. Denver and the lower elevations should have consistent snow falling from Friday evening to Saturday morning. Some weather models are suggesting that snow will continue through much of the day Saturday before tapering off Saturday night. This leads to a very cold Saturday ahead with temperatures in the 20s and 30s region-wide.

Accompanying this upslope flow will be jet stream enhancement. The Jet Stream is likely to park itself over Colorado for the duration of this event and that with enhance any snow that has formed leading to high snowfall rates across the mountains, Foothills and adjacent plains. Additionally, it is late May and the atmosphere is much more energetic than it is during the core winter months. We could be looking at some convective snow as the atmosphere will be pretty unstable. Usually, we talk about instability and convection with thunderstorms but this go around, we’re talking about further enhancement of snowfall rates. Also, this means that thundersnow could be a possibility towards the beginning of this event.

This will be a cold storm and temperatures both Saturday and Sunday morning are expected to dip into the 20s around Denver with higher elevations getting colder than that. This will impact any newly planted plants and irrigation systems that have been turned on for the season. Take the necessary precautions if sub-freezing temperatures are something that may impact you.

Another factor that is a big concern is that most of our trees have leafed. The snow that is coming will be a heavy, wet snow that will stick to elevated surfaces easily – like trees. Tree damage is going to be a major concern above 6,500 feet. It only takes 3-4″ of snow to cause issues to trees with leaves on them. Even in Denver, if the higher-end amount of snow verifies, we could be looking at tree damage as a possibility across the metro as well.

Snow Totals

Snow totals will vary greatly based on elevation but here’s what is expected to accumulate from Friday to Saturday.

NWS Expected snowfall

Areas from Rocky Mountain National Park to Bailey can expect well over a foot of snow with possibly closer to two feet actually accumulating. This would cause major issues on the roads and for trees. Along the I-25 corridor, we’re looking at 3-6″ of snow from Ft. Collins to Denver to Colorado Springs. Of course, the Palmer Divide near Castle Rock and Monument are expected to get at least a foot of snow with as much as a foot and a half falling. This will cause major issues on the roads and for trees in this area as well.

This storm over the last couple of days has been trending colder and stronger so the possibility of us getting more snow than forecast in Denver is there. The storm dynamics won’t change much for higher elevations if it comes in colder but it would have a pretty big impact to the lower elevations. Here’s a look at what can be expected snowfall-wise if this storm comes in colder and stronger.

NWS Possible high-end snow totals.

Again, in the mountains, the Foothills and the Palmer Divide, a colder storm will keep the forecast similar to what is already expected but the amount expected along the I-25 corridor greatly changes. We could be looking at a substantial snowstorm from Denver to Ft. Collins to Boulder with 9-15 inches of snow possible. Colorado Springs could also approach double-digit totals given this storm strengthens.

We will of course have to overcome a lot of warmth before the snow starts to stick which will impact snow totals but given the possibility that we could have some convective, jet-enhanced snow, we may overcome that warmth quickly.

Regardless, this will be an impactful late-season snowstorm. Probably the biggest benefit of this storm is that it is coming with a lot of moisture regardless of how much snow actually falls in any location. 1-2 inches of liquid is supposed to soak our grounds. This wouldn’t eradicate our drought but it would make a big dent. To put it in perspective, 1-2 inches of liquid is close to 10 percent of our annual moisture in Denver.

The key takeaways from this storm are: there will be a lot of snow above 6,500 feet which could damage trees and cause some power outages. Heavy, wet snow is expected in Denver and it could turn to be a very impactful snowstorm across the Urban Corridor as well. Sub-freezing temperatures will impact irrigation and newly sown plants. Finally, lots of beneficial moisture will come from this.

Enjoy the wild weather that Colorado is about to deliver and adjust any outdoor or travel plans accordingly as this storm will likely wreak havoc on our roads.

~Andy

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