People talk a lot about the huge amount of snow and rain that fell on California, where there was a drought a few years ago now clear end.
But with most of the rain heading south of the Northwest over the past month or so, where will that leave the Pacific Northwest? How’s our snowpack? Are our reservoirs full? Are we in water trouble?
Time to check this out, especially as we’re transitioning into a drier Northwest Spring.
The bottom line: Washington State’s water reserves are slightly below normal, with no serious water problems expected.
First, pack the snow. Oregon snow and ice were much higher than normal, and Washington State snow and ice were generally close to normal, although slightly below normal for the Yakima Basin and North Cascades.
Precipitation
With the “meteorological tap” heading towards California (and following a dry period in the fall), the Northwest is drier than usual. To illustrate this, below is the percentage of normal precipitation for the “water year” that begins October 1.
The Northwest received about 70% of normal rainfall this year, with the eastern slopes of the Cascades slightly above normal.
Why is it wetter than usual there? Because with persistent coastal low pressure areas, east flow (from the east) has been enhanced. Such flow is sloping up east of the Cascades, producing more rain!
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Reservoir level
Let’s start with the Seattle reservoir system. As of March 6, the reservoir capacity is slightly lower than normal (about 90% of normal).
The snow above Seattle’s reservoirs is a little higher than usual
The bottom line is that Seattle is in good shape, and the sustained cool temperatures will help maintain a thick layer of snow in the spring.
Next, let’s turn to the Yakima River reservoir system, crucial to agriculture in eastern Washington (see below). It is also below normal (about 85% of normal).
For a broader view, here is this summer’s Water Supply Forecast from the NOAA River Forecast Center. Near normal (green) for western Washington and northwestern Oregon, as well as southeastern Washington and much of Idaho.
But modestly below normal on the eastern slopes of the Cascades and the Okanogan region.
Now let me note that earlier this winter, my profession called for a cool/wet winter because of La Nina. We are cool, but not wet. We also think California will be drier than usual.
Look forward
La Nina is currently collapsing as well as its impact on global weather systems.
So what do the latest model predictions indicate?
Over the next two weeks, the European Center’s aggregator of forecasts shows that generally wet weather in the south and dry weather in northern Washington and southern BC will continue. (green and blue indicate above normal, you can guess what brown is)
Temperature? Disappointed that there is no warm-up for residents of the hot Northwest (see the next 10 days forecast below)
In a nutshell, this winter we’ve been cool and relatively dry as a result of a persistent atmospheric pattern with jet streams heading south into California. Our water situation was a little below normal but nothing serious, well within the normal range.
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The Pacific Northwest Weather Conference is the region’s premium weather gathering, and it’s back as a face-to-face meeting May 12-13 at NOAA’s Sand Point facility in Seattle. . This will be a hybrid meeting, so those of you who want to attend remotely can do that too.
At this workshop, we discuss the latest research and advances in Northwest meteorology and climate (including British Columbia) and review the major weather events of the past year.
The upcoming meeting will include discussions on advances in regional weather forecasting technology, the Portland avalanche, December ice storm, wildfire meteorology, fall smoke events, morning New ideas on media weather, regional climate change, etc.
We’ll also have a party at Ivar’s Salmon House (in Seattle) on Friday night, with an engaging speaker.
If you’d like to attend, you can get more information and register at the meeting’s website:
https://a.atmos.washington.edu/pnww/
And those interested in speaking, please send me the title and summary by April 10th.
