Wind, Waves, and Wet

This weekend, we will "enjoy" the meteorological trifecta of winds, coastal waves, and substantial precipitation.

First, the winds.

The forecast sea level pressure for Sunday at 10 AM predicts a strong 994 hPa low center to west of the Washington coast.

The associated winds (below) are impressive, with sustained winds of 50-60 knots to the south and west of the low center.    This is known as the "poisonous tail" in the weather business.

Such strong winds over a large area (large fetch) will produce large waves that will reach our coast later this weekend (see below).   These waves will climb to 45 feet offshore and over 20 feet on our coast.

There will be good wave watching on the Washington coast on Sunday.

As the low moves northward up the coast on Saturday and Sunday morning, wind gusts will increase along the Washington coast and   over the western Washington interior  

The forecast gusts at 4 AM Sunday are shown below.  Strong gusts (50 kt and more) on the coast; 30- 45-knot gusts in the interior, particularly near the water.

The UW runs perhaps the most sophisticated wind prediction system in the country for Seattle City Light (called WindWatch), and it is predicting 40 mph gusts in Seattle on Saturday night and early Sunday. (see below)

As the first major blow of the season, with lots of vegetative growth over the summer, there will be power outages.

 

My "pro-tip":  charge up your electronics and lights on Saturday.  You won't regret it.

Finally, there is the wet part of the upcoming weather.

Below is the predicted precipitation accumulation through Monday at 4 AM.  Very wet in the Olympics and the northern Cascades.  Plenty elsewhere.  Reservoirs will begin to fill.

This is just the beginning of the wet/stormy season in the Northwest, with a lot more on the way.   Typical November conditions, and there is no going back.

Precipitation Miracles

 Sometimes, higher powers respond to our supplications.  

Water behind Lake Powell

At the end of summer, the water level of Lake Powell, fed by the Colorado River, was at record lows, and there were worries about power generation, as well as supplying needed water downstream.

But then a miracle occurred:  a series of atmospheric rivers pushed into the Southwest, dropping immense amounts of precipitation over the Colorado River drainage (see below)

Rivers rose dramatically, and the water level was rapidly elevated behind the dam:

Plenty more water will flow into the Colorado River during the next week, as shown by the predicted hydrograph below for a location upstream of the dam.

But the miracles don't stop there.  

The Yakima Valley, which had low snowpack feeding the Yakima River, received localized heavy rain at the end of the summer, allowing water restrictions to end (see below; blue is much above normal precipitation).

And now the upcoming water miracle. 

 The 15-day precipitation forecasts predict large amounts of precipitation for Northern California, whose reservoirs need a refill after the summer, and the Pacific Northwest, which has been relatively dry this autumn.

Meteorology and religion have had a long association, and perhaps there is only one thing to be said: