The last storm

The storm on Thursday afternoon moved through about as expected. The highest totals I could find in the eastern foothills were around 3 inches, which was on the low end of the expected 3-6 inch range. Mountains near and west of the divide, including the two open areas of Loveland and Arapahoe Basin, saw a coating to 2 inches, which was about what we expected.

Reader photos

I love looking at my email each day and seeing photos sent in by readers. It keeps the excitement alive about snow and the mountains in general. Here are some of the best shots.

I love this last photo because Aaron said that he took his 9-month-old son on this hike as well, strapped to his chest. Since I now have a 2-month-old son, it's good motivation for me to get out and explore with just a bit of added weight training (I think Levi is around 11-12 pounds).

This weekend

I don't see much action on Friday, Saturday or Sunday. The mountains north of I-70 and along the divide (Cameron Pass, Rocky Mountain National Park, etc) will see some clouds and a few snow showers, but accumulations should be light or nothing.

Good news, crew ... it looks like we will have something interesting to talk about next week.

Over the last few days, it appeared that there would be another eastern-focused storm around Halloween. This storm looked like it would bring the most snow east of the divide with little to no snow west of the divide.

However, in the last day or two, all models are now showing that a bit more energy will cross Colorado around Halloween, and this energy could be perfectly timed to phase with lingering moisture and create a rather significant snow event for an area of the central mountains.

If this storm setup sounds complicated, that's because it is. This is not a 'simple' setup where a consolidated storm moves west-to-east across Colorado. Instead, there are a few weak features that will combine to potentially create 12-18 hours of significant snow, if everything phases just right.

The complexity of this storm means that we have low confidence in snow totals 4 days out, and that it's nearly impossible to know which small area of Colorado may wind up seeing significant snow.

Those caveats aside, all three of the major weather forecast models show a burst of precipitation on or around Halloween day.

The least accurate of the major models is the American GFS. It shows 0.5-1.0 inches of precipitation, which at slightly warmer temperatures could translate into 5-10 inches of snow.

Happily, the more accurate British model (UKMET) also shows precipitation, with some amounts over 10 inches of snow.

And the historically most accurate European model (ECMWF) is in the range of 5-10 inches of snow.

These graphics are from http://wx.graphics, a new website that offers free maps of the European and British models, which was something that previously you could not find.

Since all three major models show the storm on or around Halloween, and since the average of 51 versions of the European model also shows significant snow, my confidence is growing that a narrow area between roughly I-70 to the north and the southern mountains to the south could see a burst of heavy snow on Tuesday.

In the longer range, the weather pattern across the western US looks like it will stay active for the first 10-15 days of November. I can't promise that this means big snow for Colorado, but an active pattern in the west is generally a prerequisite for bigger storms for Colorado, so I like the trend.

Thanks for reading!

JOEL GRATZ

Colorado Forecast Page → https://opensnow.com/state/co

Next Talk

I'll be giving a talk at Bentgate Mountaineering in Golden on Nov 8th. See you there!
https://www.facebook.com/events/1209665705844183/

Charity Auction in Vail

A reader let me know about this contest. The proceeds are used to fund a local Vail educational non-profit and the winner gets a 7-night stay at the Four Seasons plus 5 nights of dining at upscale restaurants. More information here: http://opsw.co/2zEWEc4

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