Snow started to fall in the southern mountains on Monday late afternoon and then snow showers hit all mountains on Monday night. Snow reports on Tuesday morning show 1-4 inches for most areas with 7-8 inches in the southern mountains around Telluride, Silverton, and Purgatory.

Most models correctly forecasted the southern mountains to see the most snow on Monday night, so we’re in good shape so far.

However, Tuesday and Tuesday night is where all models diverge and I honestly have about as little confidence as I can in the forecast for the next 24 hours from Tuesday morning through Wednesday morning.

Here is the current weather setup. Our storm is spinning over eastern Arizona.

The forecast track of the storm is rather consistent across all models. The storm is shown as the blue color below, and you can see it track across New Mexico during the next day. And, on its heels, the next storm on Friday and Saturday will also take a southern track across New Mexico.

Storms that cut off from the main west-to-east flow of weather and track to our south are often warmer than other storms. Also, southern storm tracks generally mean that the heaviest snow will fall in the southern and eastern mountains because a direction wind from the south and east favors these areas.

Both of these situations are going to play out during the next day.

The easier forecast is for temperatures, which are currently warm with a freezing level around 8,000-9,000 feet (between the base and summit at most mountains). Readings should cool a few degrees with the freezing level lowering to 6,000-7,000 feet by Wednesday morning.

The harder forecast is for precipitation.

Based on wind direction, I anticipate that the deepest snow amounts should fall in the southern and eastern mountains. However, not all models agree with this, and the uncertainty lies in how the energy will wrap around the storm.

Think of cut-off, southern storms like a drunk person stumbling down the sidewalk - you can’t predict the timing or exact placement of each stumble. For cut-off, southern storms, the models know that the storm’s energy will ‘stumble’, but they can’t agree on exactly where this energy will go. Hence the uncertainty in the forecast.

The short-range HRRR forecast through about midnight Tuesday night shows good snow in the east and south, but also 6-12 inches in the interior central and northern mountains. I think this interior snowfall is overdone because winds from the east don’t favor the central and northern mountains. However, if some energy ‘stumbles’ over the central and northern areas, it could easily snow hard for a few hours.

In uncertain situations like this, it’s best to look at multiple models, called an ensemble. The University of Utah ensemble groups the Canadian and American GFS models together.

Here is the ensemble forecast for Telluride. It correctly showed about 6-8 inches for Telluride on Monday night, so I have reasonable confidence that the model is correct and that Telluride could get an additional 4-8 inches through Tuesday night.

Below is the ensemble forecast for Loveland and Berthoud Pass. So far, a few inches have fallen, so the model is doing ok. On Tuesday night, the model calls for about 10 inches, which is reasonable based on a wind direction from the north and east. BUT, the European model, which is not included in this ensemble, shows less snow on Tuesday night, so I am nervous that deep snow will accumulate.

And below is the ensemble forecast for Vail Pass. The model is calling for about 6 inches on Tuesday with another 4-6 inches on Tuesday night. I think this is overdone because a wind from the east does not favor Vail Pass. Of course, some energy from the storm could ‘stumble’ over Vail Pass and provide a few hours of heavy snow, but again, I think high snow forecasts for the interior central and northern mountains are overdone.

In fact, I manually lowered the snow forecasts for most northern and central mountains because the automated system based on short-term National Weather Service forecasts looked too high to me because a wind direction from the north and east often produces lower totals than most models expect.

Yes, I know this is a lot of information, and your head is likely swimming. Mine too.

To recap, expect snow showers throughout the day on Tuesday, with heavier snow likely near and east of the divide on Tuesday night. The best chance for deep, quality powder on Wednesday morning will be at the higher elevations (over 9,000 feet) near and east of the divide (including the east side of the Sangre de Cristo mountains in the south). If some energy stumbles over other mountains and they receive more than 4-6 inches of snow, I’ll consider it a lucky break.

This current storm will end on Wednesday morning, then we’ll see dry weather on Wednesday afternoon and Thursday.

The next storm will bring snow from Thursday night through Saturday night and should take a similar track to the current storm. Expect the deepest amounts in the southern and eastern mountains. In fact, the European ensemble forecast for Friday night is already showing 6-10 inches for areas east of the divide, and this is a very high forecast for a storm that is still 4 days away. Storm totals east of the divide and above 9,000 feet could be 1-2 feet.

After that, there should be another storm early next week, between April 3-5, and this storm could be a bit colder. Stay tuned for details on this system … it’s still too far out to make a confident forecast.

Thanks for reading!

JOEL GRATZ

Presentation

I am giving a short presentation in Denver on Wednesday night. This talk will be focused on OpenSnow’s business story rather than the science of weather. If business-y stuff is interesting to you, join me at the Pizza Pedal’r (2907 Huron St, Denver) from 630-800pm. My talk should start at about 710pm. More info: http://www.theknowledgeshare.org/schedule/#schedule-2

 

Geography Key

Northern Mountains
Steamboat, Granby, Beaver Creek, Vail, Ski Cooper, Copper, Breckenridge, Keystone, Loveland, Abasin, Winter Park, Berthoud Pass, Eldora, Rocky Mountain National Park, Cameron Pass

Along the Divide
Loveland, Abasin, Winter Park, Berthoud Pass

East of the Divide
Eldora, Echo, Rocky Mountain National Park, Cameron Pass

Central Mountains
Aspen, Sunlight, Monarch, Crested Butte, Irwin, Powderhorn

Southern Mountains
Telluride, Silverton – north side of the southern mountains | Purgatory, Wolf Creek – south side of the southern mountains