North Puget Sound Lowland Snow from the Other Type of Convergence Zone

 The first significant lowland snow over western Washington occurred last night, ranging from a trace to about an inch.

How it happened is quite interesting....let me explain. 

The snow started falling late yesterday evening and was associated with a narrow convergence band that was evident in the weather radar (see below).  The band stretched northwest to southeast and started near Sequim.

The band brought heavy precipitation in places and extended into the Cascades.

Why Sequim?  The driest location in western Washington!

As we will see, this precipitation band was associated with a convergence zone, in which low-level air streams came together, forcing upward motion and precipitation.

But it was different from the "classic" Puget Sound convergence zone we often talk about.

The figure below shows a schematic of the typical Puget Sound convergence zone. Northwesterly winds from off the Pacific are forced around the Olympics and then converge over Puget Sound, producing upward motion, clouds, and precipitation.   

Most of the time, this is the convergence zone we are talking about.

But there is another way to get low-level convergence over the western interior:   air moving southward down the Strait of Georgia can converge with air moving eastward in the Strait of Juan de Fuca, producing a band of clouds and precipitation.

Something like this occurred last night.  A strong, sharp upper trough moved through, causing the northerly winds in the Strait of Georgia to be particularly strong.   That air converged with air moving eastward down the Strait to create a low-level convergence zone that stretched from Sequim to north Everett.

Want the proof?  Here are the winds late last evening.  You can see the two air streams coming together.

The high-resolution UW WRF model predicted this situation (see the model forecast winds for yesterday evening below).  Shading is wind speed (in knots), and wind vectors are plotted.

You can see the converging airflows.

 

The precipitation band was narrow and well defined, as shown by the 24-h precipitation totals (below), with some locations in Snohomish County receiving over an inch of liquid precipitation.

The heaviest precipitation was associated with light snow (see totals below).

Why such modest snow?  

Because temperatures were very marginal (too warm) for snow.  Only in places with a lot of precipitation (and thus a lot of cooling from melting and evaporation) could the snow level be driven down to the surface.  Initially, precipitation fell as rain and then gradually evolved into snow and snow pellets.

Drought Deception

Northwest drought is being exaggerated by a group including publicly funded agencies, the media, local government, and climate activists.   

At its essence, it is ideological, anti-science, political, and self-serving.

This blog will go into the problem in greater depth than my analysis of last week.

The center of what might be called the Drought Exaggeration Industry is the National Drought Mitigation Center at the University of Nebraska-Lincoln, which is associated with the United States Department of Agriculture and the National Oceanic and Atmospheric Administration.  

The most viewed product of this National Drought Center is the Drought Monitor graphic, the national view of which is shown below.

To see how nonsensical and anti-science this effort is, consider the latest drought map for Washington State (released yesterday, and shown below).    

Most of Washington State is "abnormally dry" or in drought, with severe or extreme drought over the eastern slopes of the Cascades and the far portion of the state (see below).  

As shown below, this is total nonsense and inconsistent with hard data.  

Precipitation has been above normal, soils are moist, rivers are above normal levels, reservoirs are above normal, and snowpack is in decent shape.

But this wacky website does not end there.  It claims that 2.4 million Washington residents are in drought:

It states that 1,778,920 King County residents, many of whom are dealing with flooded roads, failing levees, and sodden fields, are affected by drought.

But the national drought meisters don't stop there!   They inform us that in KING COUNTY, 3266 cattle and 755 sheep are in drought.   And that thousands of acres of King County hay are in drought.

Perhaps the national drought folks should speak to one of our local cows, many of which have been moved to escape flooding (see below)

It is easy to prove that the drought claims for Washington State are entirely baseless.

For the past 90 days, precipitation over Washington has been near normal (light green or yellow) or above normal (blue and purple).

Soil moisture is above normal over much of the state and MUCH above normal over the eastern Cascades slopes, where the drought monitor graphic has moderate to severe drought.  Go figure.

Our rivers are mostly running above normal levels, some at near record levels (black dots, particularly east of the Cascades):

Reservoirs are way above normal.   The critical Yakima storage system....the fixation of the drought folks for a long time.... is not only above normal, but at levels commonly found at the end of winter.

Seattle's reservoirs are way above normal (see below) as are most of the others in the region.

What about snowpack, another fixation of the drought folks?   Good news, there has been lots of recent snow in the mountains, and most ski areas are open for Christmas. 

 Below are the latest numbers, which show a stunning recovery from a few weeks ago.  The snowpack feeding the Columbia River is now ABOVE NORMAL, and the snowpack for most of the western Cascades is 75% of normal.  More snow is expected during the next few days.

By any rational analysis, there is no drought going on.  

There will be plenty of water for all uses.  Furthermore, this is a La Niña year, which is usually good for water resources.

The unsupportable and unscientific drought talk is very destructive and counterproductive.   

It induces fear and worry in the population, particularly the most psychologically vulnerable.  It results in poor decision-making.    

Who are some folks doing this?   

Some are doing it to promote their politics and ideology.  Others to push a climate change agenda, which they either believe in or profit from.  Media, such as the Seattle Times Climate Lab, do so for clicks and financial support from activist groups.  YouTube and social media channels do it for clicks and advertising revenue.

But whatever their reasons, I hope that the current administration takes a deep look at this drought-pushing enterprise and reforms the government-supported side of the advocacy campaign.  

Wishing all of you a good holiday.

Crying wolf is a bad idea