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

A Christmas Eve Windstorm?

Some of the media are talking about a big wind event tomorrow over western Washington, and some of the amateur weather enthusiast sites have been going a bit over the top.

The truth is a bit less exciting:  the winds will get gusty tomorrow afternoon, and some people may lose power, but this is not going to be a major windstorm.  Gusts to 30-45 mph.

This was a difficult event to forecast earlier, with a great deal of uncertainty until today.  

Why?  Because we had a very small system moving directly up the coast, far harder to predict than a large cyclone moving off the Pacific.   I have seen this situation many times and have learned to be careful.

The modeling systems predicted the uncertainty, something expressed by very different forecasts of the members of our ensemble forecast systems, in which we run the models many times with small differences in their initial state or model physics.

Want some inner weather "baseball"?   

Yesterday, the highly skillful European Center and UKMET office models were going for much weaker winds.

The American GFS and NAM models were doing for a crazy strong event.  But these are generally far less skillful for systems over the eastern Pacific.  Pretty embarrassing that the U.S. models are generally inferior.  Make American Weather Models Great Again!

The latest UW forecast takes a modest low-pressure system to Vancouver Island tomorrow at 4 PM (see below).   

This graphic shows the sea level pressure analysis and there are a lot of pressure changes to the south of the low.  That means strong winds.

How strong?  Below is the forecast of maximum gusts at 4 PM tomorrow.  Up to around 35 knots over northern Puget Sound, with higher gusts in Northwest Washington.

Rainfall will be modest from this system (see the totals through tomorrow morning).  And much of that will be snow.  

How Unusual Were the Recent Floods? Did Global Warming Play a Significant Role?

There is a lot of incorrect information and false claims regarding the recent heavy rain and flooding in the Pacific Northwest.

Claims that the recent heavy rain events were unprecedented or that global warming (climate change from human emissions of greenhouse gases) was a major contributor.

The truth is that there is a long history of similar and larger events.

The truth, supported by extensive evidence,  is that global warming played a very minor role, if any.

False

False

Major Flooding Events Often Occur in the Northwest

Heavy rain and massive flooding are frequent visitors to our region, and THERE IS NO EVIDENCE THAT MAJOR EVENTS ARE INCREASING in intensity or frequency.

For example, in February 1996, major flooding in Oregon and Washington resulted in over a billion dollars of loss.

The Willamette Valley flooded in 1996

The 2006 flood event destroyed many roads and bridges in Mount Rainier Park, with massive damage along the Skagit and Cowletz rivers. 

Mt. Rainier Park, 2006

If global warming were a significant contributor to Northwest flooding, then flooding events would become more frequent or intense.

This is not happening.

Precipitation is not increasing

Most of the arguments for a global warming origin of heavy rain depend on arguments about the atmosphere "holding" more water as temperatures increase.

The problem with this claim is that many other factors modulate the location, intensity, and longevity of atmospheric rivers and their ability to produce heavy precipitation.

Let's evaluate these claims by looking at the ACTUAL changes in precipitation over our region.

Below is the wet season (November through February) annual precipitation over Washington State for 1895-2024 (below).

There is NO UPWARD trend, even as the planet warms.

Is the number of days with heavy rain increasing in our region?  

The data says no.   

To illustrate, this figure shows the number of days with heavy (2 inches or more) precipitation at Stampede Pass in the central WA Cascades.    NO UPWARD trend in apparent.  If anything, it is going down.

I have looked at many other stations...same story...no increase.

Not convinced yet?    

Let me show you something only my research group has at this time: high-resolution regional climate simulations in which greenhouse gases are increasing substantially (the RCP4.5 scenario).

This figure shows the change in the annual highest 5 days of precipitation between 2070-2100 and 1970-2000.

Very little change over WA State, but drier in CA.

The bottom line of all this is that both historical data and state-of-science climate simulations do NOT suggest an uptick in heavy precipitation from global warming forced by mankind.

Finally, there is ANOTHER major error regarding global warming and flooding in the claims noted above....in this case, dealing with snow.

Their argument is that warming causes less snow, and snow "soaks up" the precipitation, thus lessening flooding.

Wrong.    As noted by distinguished regional hydrometeorological expert Professor Dennis Lettenmaier, less snow meant LESS SNOWMELT, which REDUCES the amount of water for flooding.

In short, there are a lot of false claims about the relationship between global warming and local flooding.

The truth:

Northwest flooding is not increasing in frequency.

Northwest flooding is not getting worse.

There is little change in precipitation amounts or intensity during the past decades over the region as the Earth has slowly warmed.

Truth does matter.

The National Center for Atmospheric Research (NCAR) Must be Saved

Foolish and counterproductive are two words that come to mind regarding the Administration's plan to break up the National Center for Atmospheric Research (NCAR) in Boulder, Colorado.

NCAR is the crown jewel of atmospheric research in the nation, with an unparalleled global reputation.  

Its research covers an immense scientific range, including the development of new weather and climate models, essential research into atmospheric processes, technological innovations to deal with weather threats (such as aircraft turbulence and severe weather), and the use of supercomputers for environmental research and prediction, to name only a few.

NCAR is a primary site for disciplinary meetings and has played an important role in training generation after generation of future atmospheric students.  

My career began at NCAR.

Thus, it is more than disturbing when the Director of the Office of Management and Budget, Russel Vought, put out a message stating the NCAR would be broken up due to its "climate alarmism".

Breaking up NCAR would dramatically hurt U.S. science capability and profoundly undermine the ability of the U.S. to predict both weather and climate.

This in turn would put Americans at increased risk of severe weather, costing both lives and property.   

Yes, there are a few NCAR scientists who have been vocal regarding climate change, but that is certainly their right as American citizens. Their statements do not represent the organization, which is based on scientific excellence.

I hope that this counterproductive and profoundly damaging plan is shelved. 

U.S. weather prediction capabilities do need to be greatly improved.  

Doing so requires a strengthening of NCAR and building a joint effort with NOAA that would create the best weather simulation and forecasting capabilities in the world.

The American Meteorological Society (of which I am a Councilor), just put out a statement on the situation.

A Guaranteed White Christmas (In the Mountains)

For lovers of Northwest snow, I have good news.  

Bountiful mountain snow is GUARANTEED before Christmas.

Yes, this means you will be able to hit the slopes on some of the higher elevation regional ski areas.

Consider the latest 120h forecast for accumulated snowfall from the UW weather prediction system (below).

A big snow dump in the mountains, with over 3 feet of snow at some locations.  

What about the highly skillful European Center model snow forecast for the same period? (see below)

Same story!  Lots of mountain snow.

I know what you are thinking.  

Can we trust these snowy predictions?

Good question.  To evaluate their reliability, let's look at the NOAA ensemble of many forecasts for snow at Stampede Pass in the central WA Cascades (at about 4000 ft).

The individual forecasts are shown by the gray lines and their mean by the black line (below).

All the forecasts have lots of snow, with a mean of about 40 inches by Christmas.

You can see why I offer a guarantee.   Lots of snow is a sure thing.

So get your skis and snowshoes out.  There will be plenty of snow at the high-elevation ski areas.

Guaranteed.

Drought Exaggeration

One of the most misused terms is drought.    Certain groups and individuals are constantly using the "D" word when it is not appropriate, often to support their own agenda.

The most frequent source of the most exaggerated, unfounded drought claims is the Drought Monitor graphic, produced by a partnership between the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, and the National Oceanic and Atmospheric Administration (see the most recent graphic below).

The trouble is that these graphics are subjective and often wildly wrong.  

And they are virtually always wrong in the same direction: exaggerating the intensity of the "drought."

Want a good example?  Consider the LATEST Drought Monitor graphic for Washington State released on Thursday (see below).  It shows the conditions for last Tuesday morning

Moderate drought over western Washington, most of the Cascades, and the eastern slopes of the Cascades.  Severe drought over the western slopes of the central Washington Cascades, the eastern slopes of the Cascades, and northeast Washington.   EXTREME drought over southwest Washington.

Drought during a period of flooding, moist soils, and above-normal reservoir levels.

How can I put it diplomatically?   

This is inconsistent with reality.

Climate advocacy groups, such as the Seattle Times Climate Lab, take exaggerated drought claims like this as gospel, and hype is further. (see below)

So, When Should We Use the Term "drought"

Some groups, like the Drought Monitor folks at the University of Nebraska, call it a drought when rain or snow are simply below normal.

This makes little sense, since precipitation will be below normal half the time.  So 50% of the time we are in drought?   Silly.

And what about impacts?   A drought must produce serious problems due to a lack of water.

More scientifically grounded groups, such as NASA (below), use such a definition.

There is no way our region is in drought, by any rational definition.  

During this fall wet season, most locations received MORE precipitation than usual.  

To illustrate, here is the difference from normal over the past 60 days. Most of the state was above normal, with large areas receiving MUCH more precipitation than normal (the North Cascades).

The biggest drought concern has been the Yakima Valley and its reservoirs, with the latter being significantly below normal at the end of the summer.

Now the Yakima reservoir levels are MUCH  higher above normal (see below).

Local rivers? Most are flowing much above normal (see below).

Westside reservoir storage?  All above normal (Seattle shown below).

The water level in Lake Roosevelt, behind the crucial Grand Coulee Dam?  Above normal!

 

Soil moisture? Large areas are above normal (green colors)

The only aspect that is below normal right now is regional snowpack, but being low in mid-December is not unusual, and lots of snow is expected during the next week (and has been in the forecast for over a week).

As shown below, the snow situation for the Columbia Basin is excellent (well above normal), and the north Cascades is at 77% of normal.    The Yakima basin has about half of its normal snowpack.

A major enhancement of snowpack is now forecast, with huge amounts predicted for the Cascades during the next five days (see below). 

In short, there is no rational reason to suggest that Washington State is now or will not be in drought during the next months.      

And there's something else.

Washington State receives far more precipitation than it needs.  Thus, a modest dry period (such as last spring and summer) had relatively little impact on the economy or essential water resources.  You really should not use the term drought when impacts were not evident.