Mountain Weather Forecast

Time and Day: 0645 Saturday

The Snapshot: Light snow showers today, cooler. Heavy snow tonight and Sunday morning with very cold temperatures. Snow ending Sunday mid-morning.

The Science: Yesterday’s warm front stalled near the coast for long enough that the cool air behind it mitigated the effects of the warm-up. Stevens Pass saw 34 degrees in the base area and “sn-aining.” There is 3 inches in the base area this morning and 7 inches on the upper mountain with a nice cooling trend.

For the remainder of the day and early Sunday the Central Cascades will be under strong W-NW upper level flow with lots of unstable, moist air upstream. This pattern particularly favors Stevens Pass. The action should ramp up after 4pm, with snow becoming heavy in the evening hours and continuing through daybreak on Sunday. As the arctic air mass moves into the forecast area in the early morning hours on Sunday, it will push the moisture stream south, leaving Stevens Pass in very cold and dry air aloft. Showers should end abruptly Sunday mid-morning.

Models currently indicate a weak trough crossing Washington during the day Monday, potentially bringing a few more inches of snow. Freezing levels should be near the surface with temperatures in the teens at Stevens Pass.

The Long Range: After the trough moves through on Monday, Washington will be under cool, light northerly flow Tuesday and Wednesday. This will bring dry and cold conditions. Models currently have a ridge building over the West Coast midweek, and more active weather with seasonal norm temperatures at the end of the week.

Precipitation Ending at 4am: Today 24hr water = 1-1.25 Snow = 14-16” Tomorrow’s 24hr water =  .25 snow = 2-4 Trend and Timing: Light snow showers should continue during the day Saturday, becoming heavy after 4pm. Heavy snow will continue all night and into Sunday morning, ending abruptly mid-morning. Day 2 precip amounts will mostly fall in the first few hours of that 24 hour period.

24hr temperature ending at 4 am tomorrow:                                        Low:  22   High: 30 Freezing level: 3500-1000 Trend and Timing:    Temps will rise a little during the day time warming, but mostly remain cool. The arctic airmass enters our region after midnight bringing a strong cooling trend for Sunday morning.

24hr Winds (mph) ending at 4 am tomorrow: Base: W 10-15 Ridge Top: W 20-30, Gusts to 45 Trend and Timing:  Gusty westerly winds will strengthen throughout the day Saturday, peaking overnight. Ridgetop winds should turn more NW Sunday morning and relax to the teens. DV