Mountain Weather Forecast

Weather Synopsis

A warm front will lift from south to north across the area tonight before stalling out across the north Cascades on Wednesday.  The associated low pressure center will rapidly deepen and likely track northwards along the OR/WA coast.  There's still considerable uncertainty for an event less than 24 hours away, but a consensus is building that this will result in a significant wind event later tonight and Wednesday.  ESE winds will become strong at the Pass level late tonight, and even stronger on Wednesday morning, with extreme winds possible for the foothills gaps along the west slopes of the Cascades. Higher up in the mountains, winds will be more SE-erly at ridgeline and see similar timing trends.  The strongest punch of winds should come as the low tracks toward the Canadian border for areas near and espeically west of the Cascade crest including the Olympics, Mt Hood and Mt Baker area during the afternoon hours.  The Crystal area will see strong to extreme winds earlier in the day. The winds will also be howling along the east slopes of the Cascades during this pattern.  Wherever you are, saturated soils have made treefall an ongoing hazard the last few weeks, and this windstorm will batter trees from a different direction than our AR events (SE-S vs WSW).  A more inland track with a weaker low-pressure system would limit the severe wind potential. 

Snow levels will slowly rise tonight, and then rise more rapidly on Wednesday as warmer air likely floods into the region.  We should see a few inches of snow, mainly along the east slopes of the Cascades tonight, and then several more inches, especially for the north Cascades as the frontal boundary stalls. Another hot spot will be the eastern slopes of the Olympics with heavier precipitation due to upsloping. As the warm front lifts north and precipitation starts to taper from south to north, expect to end on a dour note with light rain or drizzle up to mid-elevations.  Behind the front, we may see strong showers as the flow changes from SE to SW, peaking over the West South and Mt Hood area on Wednesday afternoon. 

The weather quickly quiets down Wednesday night.  On Thursday a weak upper level disturbance ejects northward over the area, bringing light precipitation and snow levels between 3500-5000'.  The Christmas Day system will not be nearly as strong wind-wise as Wednesday's system.