Big Week Ahead for the West

Several rounds of storm systems will bring accumulating snow to the western US this week. The storm to watch will be on Wednesday and Thursday with heavy snow accumulations forecasted in the Northwest, Montana, and Wyoming. 

This storm's moisture will reach further south through the Sierra, Wasatch, and Colorado with light snow accumulations. 

The end of the week will see another potential storm system bring accumulating snow throughout the West, but model uncertainty makes the forecast on Friday, October 27th and into the weekend uncertain.

Check out the 5-day snowfall totals over the western US this week! 

Forecast for Mon (Oct 23) to Tue (Oct 24):

As the first storm system of the week clears the western US on Monday, the second storm system will move into the Northwest from Canada on Tuesday evening. This storm system will have more moisture and colder air. Snow accumulations will be heavier further north into Canada as the storm swings south in this time frame.

The remnants of Hurricane Norma will move rain through the Southwest and into areas of the Midwest on Tuesday.

Forecast for Wed (Oct 25) to Thu (Oct 26):

The storm system in the West will strengthen and bring heavy snow with lowering snow levels. Snow accumulations will be heavier further north through the Northwest US with the bullseye looking to be northwest Wyoming and Montana. This could be a storm to get bases started throughout the season.

As the storm moves south, moisture will dry out and bring light snow to areas of the Intermountain West through the Sierra, Wasatch, and northwestern Colorado. The Sierra could see more snow than the model forecast below, but mode uncertainty regarding how far south precipitation moves makes the forecast uncertain. 

Moisture will continue to move through the Southwest and into the Midwest, as well as the Great Lakes and northern New England.

Forecast for Fri (Oct 27) to Sat (Oct 28):

The forecast becomes uncertain toward the end of the week. A storm system could move into the Sierra on Friday and bring light snow through the Western US. The Sierra, Wasatch, and Tetons would be favored with this storm. 

The other option is that the storm impacting the Sierra is much weaker, but gains strength and moisture over the Intermountain West, favoring snow in the Wasatch and Colorado. 

Moisture will continue through the Midwest and bring light snow accumulations as rain falls further south and into the Northeast. 

Outlook for Sun (Oct 29) to Thu (Nov 2):

The weather pattern looks to get complicated in the extended forecast if it wasn't complicated already. There will be active weather throughout the US, but the storm track looks to be narrow with some areas seeing rain and snow, while others stay warm and dry. 

• Cooler temperatures will favor the western US and the Midwest, while the East remains warm
• The Midwest and East will see active storms, with snow possible in the Upper Midwest
• The West will see a narrow area of active weather through the Sierra and into Colorado
• The Northwest and Southwest will be drier than normal

The best way to look at this is via the Climate Prediction Center's (CPC) 6-10 day outlook, which is from Saturday, October 28th through Wednesday, November 1st.

After Thursday, November 2nd all of the western US could get in on more active weather.

Thanks so much for reading! Next update on Wednesday (October 25).

Zach Butler