Mountain Weather

It's a warm, wet, and windy day across much of the forecast region. A frontal system will continue to bring rain and high elevation snow to the Pacific Northwest this afternoon and evening. You may encounter periods of heavy precipitation and gusty winds. The storm peaks in the evening, before quickly exiting to the south and east. By Sunday morning, all the lingering showers should be wrapped up, except for areas along the Columbia River like Mt Hood and Mt Saint Helens. 

While it seems fairly certain that most locations in Washington start Sunday dry, after that, all bets are off. A short wave feature tries to lift precipitation northward out of Oregon, but weather models don't agree on how far into the Cascades it reaches or how much moisture it brings. Some show isolated showers all the way to the Canadian border, while others keep nearly the whole state dry. Not surprisingly, there's low confidence in exactly how this will play out. Even still, a few trends emerge. The best chance for precipitation will be from about I-90 southward. The further south, the more likely you'll see rain and snow. Precipitation should be about equal on both sides of the Cascade crest. Locations further north and west could see significant sun breaks. And the winds should generally be light. This pattern (and problem) continues Sunday night. 

A low pressure system passing to our north spins a wave of moisture into the Pacific Northwest on Monday. Even though it doesn't appear like a lot of moisture is associated with this feature, colder air should allow for snow to accumulate near and below pass elevations. Moderate westerly winds help showers continue to wring out a few more inches of snow, mainly near and west of the Cascade Crest, through the day. 

We're in for a warm, wet, and windy day across nearly all of the forecast areas on Saturday. A well defined N-S oriented band of precipitation has already arrived in the Olympics this morning. Rain and snow will spread inland, first to the Mt Baker area early this morning and then to the Central and Southern Cascades before lunchtime, and finally to Mt Hood in the early afternoon. Stormy conditions with periods of heavey precipitations and gusty winds are expected for the western Olympics, North Cascades, Snoqualmie Pass, and Mt Rainier areas. Unfortunately, temperatures are still very mild across the region. So, while this storm comes with a general cooling trend, snow levels will initially remain well above most trailhead locations. 

The storm peaks in the afternoon and early evening, with precipitation easily spilling over the crest to locations further east. The bulk of the storm moves south and east of the area, with post-frontal showers focusing mainly near and west of the crest. For most locations, precipitation continues to taper overnight and finally ends before Sunday morning. The exception is Mt Hood, where the storm is just getting started. A short wave system arrives early Sunday morning, reinvigorating precipitation and lifting a band of heavier rain and snow northward from Oregon. Models disagree about how far this will reach into the Cascades, but the best chance of rain and snow seems to be from about I-90 southward. Cold air with this second storm should help snow levels fall further, closer to trailhead elevations.