We have two good days for hitting the mountain this 3 day weekend, which of course leaves one that definitely won’t be so great. That would be Sunday.
Why the rain on Sunday? A warm front with steady rain pushes into the Cascades after sunset Saturday. That will be followed by snow levels up around 8,000′ (way above the tree line) through Monday. The flow of air at 5,000′ will be straight from the west at 35-50 mph all day Sunday; that means moist air runs right into the Cascades, is forced to rise, and dumps rain over and west of the Cascade crest. That’s called orographic lifting and will give us some big rain totals for about 24 hours. It appears this event is going to be quite extreme with respect to the rain totals…unusually light in the valleys and unusually heavy in the mountains. Our RPM shows 3-5″ of precipitation in the south Washington and north Oregon Cascades over the next few days…much of that falling in the form of rain after sunset Saturday.
The good news is that the band of rain lifts north Monday and should leave us with a dry and spring-like day on the mountain. Hopefully the snow won’t be too saturated with water; most likely it’ll be okay since we have 4 to 8 feet on the ground at the base of the ski areas.
Here in the valleys the weekend will be wet, with most rain during the midday/afternoon Saturday. Sunday’s rain should be lighter.
We may have a 60 degree day (or warmer?) on tap for Monday. If clouds lift far enough north we will be in the sweet spot with some sunshine, very warm atmosphere, and light southerly breezes.
Chief Meteorologist Mark Nelsen