Mountain Weather Forecast

Weather Synopsis

A moisture laden cold frontal system is pushing through the mountains as I write, leading the edge of a trough that will settle into the area for at least the next few days. This will drive our weather pattern going into the weekend, bringing much colder temperatures, snow and elevated winds. The southern part of our region has been first in line to the action as the initial precipitation shield rotates in from the southwest. Increasingly strong south to southwesterly winds should quickly turn back to west as the front passes. Behind it, we'll see snow levels start to drop, eventually landing around 500ft by Friday morning.

As the front digs through it'll bring cold air and snow showers that push east of the crest overnight on strong westerly flow. With ample moisture streaming in, and much colder air in place, we can expect continued showery snowfall on Friday. Westerly winds should continue to blow in the moderate to strong range at ridgetop. Afternoon convection may lend itself to heavy snow and graupel showers at times. Later Friday afternoon into the evening, we may see another uptick in snowfall rates along with chances for convergence zones to set up between the Mountain Loop and Snoqualmie Pass. 

On Saturday morning we'll see the coldest temperatures of the period. Snow levels should hit sea level in most places as the weakening jet stream coincides with tapering snowfall and winds. At this point it appears the majority of the energy will be focused on the southern half of the region-especially the southwest Cascades and Mt Hood. The general trend is that snowfall and winds will become light and scattered by Saturday morning, but afternoon convection may fuel another round of moderate snowfall. With this pattern, the east slopes are likely to see increasing sunshine on Friday and Saturday, and patchy convective snowfall.