Cliff Mass’s weather blog: Winter-like system in May

Tomorrow won’t be like late May, with a winter-like Pacific weather system making landfall, bringing more rain, wind and cool temperatures.

Latest infrared satellite images show a strong weather system moving in from the Northwest; It will arrive around dawn tomorrow.

The whole day was cloudy and humid. This is the cumulative rainfall forecast before 5 p.m. The entire western side of the area will cover a few tenths of an inch, with more than an inch in the mountains. Not a good day of walking.

Rain will continue through Wednesday, with cumulative totals through 5 p.m. reaching impressive levels (2-4 inches) in the mountains.

This floodwater will have a very positive impact on the westerly flow, which is currently running below normal levels.

Consider the Snoqualmie River at Carnation. The National Weather Service’s latest forecast calls for rates to accelerate to near historic maximums before falling back to near normal levels (below).

And then there are the winds! The approaching disturbance will produce wind gusts of 20-35 mph tomorrow afternoon and evening, which could cause some branches to fall on newly leafed trees (see latest forecast below from Seattle WindWatch .

Temperatures will only climb into the low 50s tomorrow, about 15F below normal!

I suspect May rainfall totals will be near normal by the end of this event at most stations, making up for the dry period earlier this month. And good wetting will help fill reservoirs, reduce water use and push the wildfire season forward in time.