Spring Storm Swings into Colorado Midweek - Valid 03-14-2023

Statewide Weather Alerts

For the mountains:

Winter Storm Warnings in effect (pink shaded areas)

In effect Wednesday and most of the day Thursday
Heavy snow with some places seeing up to 2 feet of total accumulation
Strong winds at 40-50mph with blowing snow and poor visibility
Dangerous travel conditions, travel not recommended

Winter Weather Advisories in effect (purple shaded areas)

In effect Wednesday and most of the day Thursday
Snow accumulations between 6-12 inches
Wind gusts at 40-50mph causing blowing snow and poor visibility
Travel will be difficult through these areas

Currently there are no winter weather highlights for Colorado Front Range or Palmer Divide

Snowfall and Storm Uncertainty

I've posted the following graphic to highlight the considerable uncertainty shown on the latest model runs. Most of Northeastern Colorado including the Palmer Divide has low confidence and high uncertainty for total snowfall amounts. This amounts to a couple of things:

Temperatures will be cooler but marginal for snow accumulation
Timing and strength of the storm system
Moisture setup and best upslope - many models still struggling with this

As such, here's the trend we are seeing in the models:

Sharp North/South and East/West gradients in snowfall accumulation - this will make a lot of totals for specific areas difficult to nail down
Only very favored upslope areas will see decent snowfall accumulation - this will ultimately come down what direction the wind comes out of and how intense it is for the best upslope. This means snowfall amounts could be highly variable over relatively small geographic areas
Most models are not excited about snow at all with this system East of the Foothills - except for the Euro. Will be watching these trends into Tuesday night and Wednesday morning

Timing and Impacts

Attached below is a impact index graphic that should give you a bit of an idea of the times we are watching and the level of impacts. Keep in mind, the timing and severity of a forecast like this can shift based on forecast data, so keep an eye out for any changes.

The main impact time with this storm looks to be late Wednesday and through Thursday morning. Exactly when things start to get rolling Wednesday and when they stop Thursday is still a bit up in the air - but the trends I've seen so far don't give me a lot of confidence in thinking that we see much impact on Wednesday night until much later into the overnight hours.

As such, I would expect the Thursday morning commute to have a better chance at seeing some impacts than the Wednesday evening commute. That being said, you'll notice the impacts remain fairly limited in all categories - in other words this isn't looking like much of a storm that does anything outside of causing a few headaches.

Snowfall Forecast

The snowfall forecast for the major regions of Colorado is below. You'll notice the wide spread in snowfall ranges, this is because of two things:

Warm air temperatures (relatively speaking) and warm ground temperatures could mess with how much accumulation we see
Models are still bouncing a lot on these snowfall numbers

The numbers you see below represent a best guess/blend of the data I've seen so far. If any adjustments are to be made in the next 24-36 hours, I'd imagine we adjust towards the lower end of these ranges rather than the higher end.

Regardless, these spring storms can throw curveballs every now and then so we'll have to keep an eye out for that.

Palmer Divide