Weather Synopsis for Tuesday & Wednesday

We're in store for a nice day in the mountains with mostly sunny skies and light winds. After a cool start to the day, expect temperatures to warm up with freezing levels rising to 3500-4500 ft. Scattered low-level clouds may build up slightly along the E slopes of the southern Washington Cascades in the afternoon. A broad upper-level trough extending from central Canada will stay over our region through Tuesday night. On Tuesday night, an approaching low and associated frontal system will draw colder air southward along the E slopes of the Cascades and also through the Fraser River Valley overnight. This will bring subfreezing temperatures to most elevations along the E slopes of the Cascades by Wednesday morning.

The aforementioned warm front lifts northward on Wednesday. Light snow develops around Mt Hood in the morning hours as mid and high clouds will fill in the few sunny areas near the Canadian border. By the afternoon, as snowfall becomes moderate intensity for Mt Hood, light snowfall spreads into the southern Washington Cascades, southern Olympics, and areas north of I-90 by the end of the day. Increasing light SE or ESE ridgeline winds become moderate in the afternoon. Don't be surprised to find a few inches of snow even at lower elevations along the E slopes of the Cascades by the end of the day with upslope enhancement. Snow levels should be in the 1000-2000 ft range for the Cascades and around 3000 ft for the Southern Olympics.