Northwest Mountain Snow in June: A Cold/Wet Period for the Northwest

The images from the Mount Rainier Lodge area during the last day were winterlike, with several inches of snow on the ground

The Crystal Mountain ski area was similarly snow-covered.

And Whister Peak appeared more like March than June 

Thunderstorms, with small hail, hit both sides of the Cascades, with substantial precipitation totals yesterday (Saturday); many mountain locations received over an inch of liquid water.

This situation has brought much colder than normal temperatures to the region, with many locations 10-20 F below climatology ( see below).   Many higher terrain locations did not get out of the 30s!

But even colder and wetter weather is in the forecast, with major positive implications for water resources this summer.

The forecast temperature anomaly (difference from normal) for the region for Tuesday to Wednesday morning (below) is for 5-15F below-normal temperatures, with the coldest temperatures over the Cascades and eastern Washington and Oregon.

Wet conditions will dominate from late Monday into Tuesday morning, with some locations in the Cascades receiving 1-3 inches.    Very favorable for water resources this time of the year: moistening the soil, filling reservoirs and rivers, and reducing water demand.

The origin of this cold/wet period is anomalous low pressure (roughing aloft in meteorological parlance), as shown by the upper-level  (500hPa, roughly 18,000 ft) forecast map for Monday at 5 PM.  Blue indicates the low/pressure/troughing

Temperatures should recover a bit by the end of the week (see forecast through Friday for Seattle, shown below), but we will have to endure a cool/wet period first.

Wet, Cool Winter-Like Weather in June

During the next week or so, the weather will be more reminiscent of February than June, with lots of rain and MUCH colder than normal temperatures.  

Reservoirs, already above normal, will be topped off, streamflows will be substantially enhanced, and soils moistened.

Let's begin by looking at the predicted precipitation totals (by the European Center Model).

Through Friday, some regional light rain (see below)

The totals through Tuesday morning are getting serious, with windward (western) slopes and higher terran of the region wetted by as much as 2-3 inches.

Values of cumulative precipitation over the next 15 days are quite extraordinary, with substantial rain even falling over eastern Washington.

Now I will show you something hard to believe.  

A very, very strong atmospheric river will be aimed right at us on Sunday evening (a measure of the amount of water moved by the atmospheric river is shown). 

Just stunning.

Not only will it be wet, but much colder than normal, which reduces evaporation considerably and encourages water to percolate into the soil.  

Below is the forecast difference of temperature from normal for the next five days.  

Brrr! The whole region is 3-6F colder than normal,

Next five days?   Double Brrr!   The entire region remains cold!

The NOAA Climate Prediction Center is going for wetter than normal for their 5-10 day forecast:

And the NOAA Northwest River Forecast Center predicts that local rivers will rise substantially.  For example, consider the Yakima River, which is of prime interest these days.  Big jump upwards.

Having an extended cool, wet period at this time of the year is extremely favorable for both water supply and agriculture.   

Hopefully, the "extreme drought" hype will fade now.