Mountain Weather Forecast

Time and Day:  0645 Sunday

The Snapshot: Moderate snow during the day Sunday, much warmer, dry, and partly to mostly sunny on Monday.

The Science

If you think it’s been a wet April so far, consider this from the NWS discussion: 

The rain yesterday pushed the monthly rain total at Sea-

Tac past the 50 percent mark for the normal for the entire month

( 1.37" through the 7th versus the entire monthly normal of 2.71"

). There is a good chance by next weekend most places in Western

Washington will have already surpassed their April monthly normals

for rainfall.

Current Observations:  It is currently snowing with 6” of lower density overnight, and 8” in the past 24 hours. Temperatures have cooled off a bit with 33 degrees in the base area and 30 on the upper mountain. The high winds never materialized and they are currently light from the west. The barometer has begun to edge back up as yesterday’s low pressure center fills.

The Forecast: As the low pressure center becomes more of a trough, westerly flow will continue to bring snow showers and moderate winds to the Cascades today. Areas exposed to SSW winds are seeing the highest winds and heaviest precipitation. As mid-level winds shift to due west midday Stevens may see some higher gusts, but operationally significant winds are not expected. Precip type should remain snow through early Monday morning before ending altogether. With an approaching ridge of high pressure and daytime warming, there are no guarantees that Sunday afternoon won’t end up a little soggy.

High pressure is still on track for Monday, with freezing levels soaring to 8000’ or higher. A sunny day is in store for most areas. This will be short lived as the next system in SW flow approaches Monday night.

The Long Range: A weak and warm system arrives Tuesday with moderate precip, likely rain at first, possibly turning to snow late. Another front arrives Wednesday with slightly lower freezing levels. The rest of the week features Wet Weather for Western Washington.

24hr values daily 4am to 4am.

Precipitation: Sunday’s   24hr water: .75    Snow:  6-8” Monday’s   24hr water:  <.10    Snow: trace Trend and Timing: Moderate snow during the day Sunday, ending Sunday night or early Monday morning.

Temperature: Low: 29    High: 35 Snow Level: 4000-4500’ Trend and Timing:    Approaching warmer air and daytime warming will raise temps in the afternoon.

Winds Base: W 5-10 Ridge Top: W10-20 Trend and Timing: Moderate ridgetop winds and gusts are possible midday Sunday.