Mountain Weather Forecast

Weather Synopsis

The see-saw between spring and winter weather patterns will continue over the short term and eventually tilt in favor of winter. Mountain temperatures are in the upper 30s to 50s this afternoon under mostly sunny skies. A quasi-stationary frontal boundary that's been hung up to our north will finally slide south overnight but we will squeeze out one more mild night with high freezing levels. We can expect increasing mid and high clouds overnight as well as increasing southerly winds for places like Hurricane Ridge, Mt Baker and Crystal Mt.   

Forecast models have a poor handle on the exact timing of the frontal passage Thursday night, but it should pass through the Cascades before daybreak give or take a few hours.  There will be a period of moderate to heavy rain/snow along with those gusty winds for the Mt Baker area as snow levels crash to around 4500-5000' with the onset of precipitation. The heaviest post-frontal showers on Friday morning will shift from the Mt Baker area to the Mt Loop/SR 20 West corridor, likely in the form of a Convergence Zone, with lighter showers elsewhere.  

As the trailing upper level trough trickles overhead Friday afternoon with much colder air aloft, shower activity should increase and the Convergence zone may start to shift south towards Stevens Pass. Look for strong westerly winds to develop for all areas during the day, especially Friday afternoon. That area of more moderate showers should shift further south towards Snoqualmie Pass Friday night. Snow levels will continue to fall through Saturday morning as we sit on the backside of the cold upper level trough. An upper level shortwave sliding down in NW flow should reinvigorate shower activity Saturday afternoon with yet another convergence zone forming and focusing over the central Cascades.