Cascade Mountain Weather

Mountain Weather & Snow Forecasts for PNW Backcountry Enthusiasts

Sub-seasonal Outlooks

Roughly week 2 through week 6. Skill is low, so read these as shifts in the odds toward warmer or colder, wetter or drier than normal, not as a day-by-day forecast.

ECMWF extended range (weekly averages)

The ECMWF ensemble run out to about six weeks, shown as weekly averages for the sub-seasonal range (weeks 2 to 6). Pick a week to compare precipitation, temperature and the 500 hPa pattern side by side, or pick a product to compare the weeks.

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Climate Prediction Center (NOAA)

The CPC 6–10 and 8–14 day outlooks show the probability of above or below normal temperature and precipitation. Colors show the favored category and how strongly, not how much.

CPC 6 to 10 day temperature outlook
6–10 day temperature outlook
CPC 6 to 10 day precipitation outlook
6–10 day precipitation outlook
CPC 8 to 14 day temperature outlook
8–14 day temperature outlook
CPC 8 to 14 day precipitation outlook
8–14 day precipitation outlook

Source: NOAA Climate Prediction Center. Also see the week 3–4 outlook.

CW3E (UC San Diego)

CW3E sub-seasonal products start up for the cold season and will appear here: atmospheric river activity for weeks 2 to 4, an atmospheric river outlook for Seattle, and the West Coast weather regime forecast.

What we plan to add

Our summary

A short weekly note in plain language: what the outlooks agree on, where they disagree, and what it could mean for the snowpack.