Mountain Weather Forecast

Time and Day:  0730 Saturday

The Snapshot: Light mixed precip during the day Saturday with increasing winds and lowering temperatures. Moderate snow and cooler on Sunday.

The Science

Current Observations:  Rain started early this morning, with a burst of moisture around 5am that has tapered to light mixed rain/snow showers. Temperatures are 35 in the base area and 32 on the upper mountain. Winds are easterly and light to moderate. The barometer has fallen sharply and is at 997 currently.

The Forecast: The above image shows a deep low pressure system off the coast which is directing southerly flow and a strong warm front across the region this morning. Topography is helping to limit precip amounts at Stevens Pass as we are in the rain shadow, and easterly flow is keeping temperatures lower than free air freezing levels would indicate. With 45 degree overnight lows on the eastside however, it isn’t quite enough. As the low moves inland colder air and westerly flow will move in behind it. This should drop freezing levels to 4,000’ after 5pm on Saturday. Light snow Saturday night should ramp up on Sunday morning, with moderate snow showers likely during the day Sunday.

Sunday night a high pressure ridge builds over Western Washington. This will bring an end to showers and provide for a partly sunny, warm day on Monday

 

The Long Range: After a mild day on Monday another system arrives on Tuesday. Freezing levels look a little high, with another mixed precip event likely. Active weather continues the rest of the week with a colder system on Wednesday bringing moderate snow amounts.

24hr values daily 4am to 4am.

Precipitation: Saturday’s   24hr water: .5-.75     Snow:  2-4” Sunday’s   24hr water: .75-1.0     Snow: 8-10” Trend and Timing: Light mixed precip with no snow accumulation during the day Saturday, turning to all snow Saturday night with moderate snow on Sunday.

Temperature: Low:  30   High: 38 Freezing Level: 7000-4000 Trend and Timing:    High free air freezing levels (locally lower at the pass) should lower during the day Saturday and further Sunday morning.

Winds Base: E 5-10 then W 5-10 Ridge Top: E 5-15 then SW 15-20 Trend and Timing: East flow will end Saturday morning, with increasing WSW winds Saturday night and Sunday morning.