MOUNTAIN WEATHER FORECAST

Time: 0900

The Snapshot: Snow has begun falling at Stevens and will intensify through the day and night as a strong winter storm moves through the state.  Winds will also be a factor today with gusts topping 40mph.  Snow will taper to showers tomorrow but continue through the weekend.

The Science: This morning’s radar (0600) has the leading edge of the approaching storm entering the north Puget Sound area.  The highway 2 corridor from Everett east already has signs of Convergence Zone development, hence the snow falling at the Pass.   The leading edge of the warm front is expected to swing through the mountains sometime this afternoon.  A cold front will follow late tonight lowering freezing levels and changing snow to showers. A relatively healthy stream of moisture is being entrained, so moisture contents may be high.   Storm totals by noon tomorrow = 12-16” of snow. Enhanced orographics (upslope snow fall) could push snow amounts higher than models indicate.   

4-7day Long Range: Snow showers will continue through Sunday. Monday will be fairly dry with another system entering the region on Tuesday.   Tuesday’s storm is tracking in from the SW which usually is associated with warm southern air.  A bit too far out to be reliable but freezing levels will probably be high with rain possible.    

24hr Accumulative Precipitation Totals Starting at Noon Today:   Water by 4am = .75-1 Snow equivalent = 8-14”   Total inches of water by noon tomorrow = 1 -1.25 Total inches of snow by noon tomorrow = 12-16”   Trends and Timing:   Snow will intensify through the day.  There will be a temporary rain snow mix later this afternoon or early evening with the passing of the warm front.    Snow will change to showers through the early morning hours and taper off in the afternoon.  Snow showers are expected to continue through the weekend.

24hr Base Area Temperatures (F) Starting at Noon Today:                                        Low: 24    High:34 Freezing level: 4000’      4500     3000’   Trend and Timing:      Freezing levels will briefly spike to 4500’ with the passing of the warm front later this afternoon or evening.  Temperatures will then sharply decline through the night with freezing levels dropping to or below 2500' tomorrow.

24hr Winds Speeds (MPH) Base: 15-20 W gust above 40 possible Ridge Top: 20-30 W gusts topping 50mph possible   Trend and Timing: 5000’ wind models show 60+knots for this afternoon and evening with sustained winds above 30mph.  Winds will begin to diminish tomorrow morning but remain gusty throughout the day.