Colder and Snowier than Normal in the Northwest: This is NOT the El Nino Pattern

The Northwest atmosphere did not get the message about El Nino this week, with colder-than-normal temperatures and substantial snowfall in the mountains.

For example, a veritable army of snowplows moved through Snoqualmie Pass this morning

See the video here.

Stevens Pass was quite snowy this afternoon

The visible satellite image this morning was a classic, showing instability showers offshore, the result of cold Arctic air passing over much warmer water.

The radiosonde sounding (balloon-launched weather instruments) at Forks indicated a freezing level of around 1300 meters above sea level (around 4200 ft).   The snow level can be as much as 1000 ft below that.  

No wonder the passes got snow.

With the cold/snow conditions over the region, several mountain locations have had above-normal snow amounts the last few days (see below). The blue dots indicate stations with over 150% of normal snow!.  That does say much this early in the season.

The colder-than-normal conditions, with more mountain snow, are not over!

The forecast of the temperature anomaly from normal shows for the next day indicates that the whole Northwest will be colder than normal (blue and green colors).

And colder-than-normal conditions will continue over the region for the next week!

The result will be additional early-season mountain snow, as shown by the predicted accumulation through Sunday afternoon (below).

There has been a lot of loose talk about coastal Kelvin waves and warm ocean conditions off our coast, but our water temperatures are actually quite close to normal (see below).

The warmer-than-normal coastal waters are mainly to our south over central and southern California and offshore far to our southwest.

Finally, the models are emphatic that there will be a major weather regime change in a week, when a series of potent atmospheric rivers will aim directly at our region (see below). Should really help to fill reservoirs.

Quite a contrast to classic El Niños that take the moisture plumes into California.

All in all, good news for water resources in the Northwest.

The Stratosphere Plummets over Seattle....and Huge Precipitation Contrasts

Today, the stratosphere was much, much closer to you than normal, and we all lived to tell the tale.

As many of you know, the lowest layer of the atmosphere is the troposphere, where nearly all the weather occurs (see below).  Temperature generally decreases with height in the troposphere (red line)

Above the troposphere, there is the stratosphere, where the temperature increases with height...first slowly, then rapidly.

Temperatures are warm near the surface due to the heating of the surface by the Sun, while aloft the heating is due to the absorption of ultraviolet radiation by the ozone layer.

Over our region, the boundary between the troposphere and stratosphere (the tropopause) is typically around 35,000 ft... just a little above the typical cruising altitude of jet aircraft.

You can often see the boundary from your aircraft window.   Clouds and haze in the troposphere, clear air and blue skies in the stratosphere (see below)

Something dramatic happened this morning to the boundary between the two layers (again, the tropopause).

It plummeted from roughly 35,000 ft to around 23,000 ft.  

If you were flying above western Washington this morning at typical cruise altitude, you were deep into the stratosphere, with lots of ozone being ingested into the aircraft.

How do I know the stratosphere was that low?   

Because there was an ascent of a National Weather Service radiosonde (balloon-lifted weather instrument) that showed the situation clearly.

Here is the plot, with red being temperature and blue dew point.  Temperature stopped cooling, and air became very dry (indicated by the dew point declining rapidly) around 400 hPa pressure, which is found around 23,000 ft.

Weather forecast models create a map of the height of the tropopause, and one was shown before 5 AM this morning.    

It is very high over the warm tropics and lower near the poles.  

But there are also complex distortions in the height of the stratosphere over the midlatitudes and polar regions, and one such structure was over our coast, with the blue color indicating a downward distortion of the tropopause.

Weather balloon went right into this.

This local distortion of the tropopause was due to a well-defined upper-level trough this morning, indicated by the blue colors and the low "L" in the figure below

How unusual was the descent of the stratosphere to 23,000 ft this morning?   I checked the radioaodne data for the last 50 years.   

It was the tenth-lowest excursion in October on record.

Impressive.

Finally, since I am talking about impressive things, how about the total precipitation around the Olympics over the past 48 hours (below)?

Nearly five inches on the southeast side and 0.17 inches on the northern flank near Port Angeles. 

We are talking about a factor of over 25 times!  

Why did this occur?  

With the low offshore, strong moist winds approached the Olympics from the southwest and were forced to rise, releasing a large amount of moisture as rain.  

On the northern side, the air sank, was warmed by compression, and the relative humidity dropped, killing any precipitation.

You got to love living here... 👴