Thursday, April 23, 2015

Wetter weather ahead for Friday and Saturday

In a year with low snowpack, getting rain during mid to late spring is crucial for reducing water problems during the summer.  The water delays the beginning of watering/irrigation season, leaving more water for later use.  And the water can go right into the region's reservoirs, which no longer have to worry about holding storage for potential flooding.

The past 24h brought a few tenths of an inch over the region, and nearly 3/4 of an inch over the windward side of the Olympics (see graphic).

And some wet prospects are ahead:   here is the National Weather Service GFS model forecast for cumulative rain over the next ten days. Western Washington and the Cascades do well, at least several inches, and even northern California gets moderate rain.

Friday and Saturday will be influenced by an upper-level trough that will maintain cool, unstable air over us (see upper level map for Friday morning),   Typical spring shower regime with low snow levels.

Looking at the next 72 hr precipitation over the Northwest from the UW WRF model, there is substantial rainfall ahead, with 1-2 inches of liquid water over the North Cascades and Olympics.

Perhaps more importantly, some of this precipitation will be mountain snow with 1-2 feet in portions of the north Cascades.

The latest extended forecast by the NOAA Climate Forecast System model (CFSv2) for the next three months is suggesting normal precipitation, except for right along the coast (see map).
I believe the media and some local politicians have gotten a bit too worried about our "drought."   We have not had a precipitation drought at all....we are in a snow drought due to warm temperatures.  The situation is unique and I suspect we will weather this summer far better than expected.  And for those looking for outdoor activities this weekend:  Sunday morning and early afternoon look the best.


Michael Riordan said...

Thanks, Cliff, I'll continue to put my garden in Friday and Saturday and plan to go kayaking on Sunday!

Brian Blackmore said...

Friday morning showed 1" of fresh powder on Mailbox. With the winds, persistent overcast, and a few flurries, it was the closest to a winter hike I've had since summer.

Unknown said...

Amazing warm day, which I imagine you are writing about right now. Hey, general question, the 72-hour precipitation forecast maps have what I find to be an un-intuitive color scheme, and I'm wondering how that happened. I have to look at the legend just to interpret each color.