January 31, 2021

The Extreme Protection of the Rocky Mountains

The Rocky Mountains,  a few hundred miles to our east, offer profound protection for our region from the bitter winter cold of the interior of North America.

During the next week, this protective shield will be put to a severe test and will not be found wanting.  Let me show you.

The terrain map below show the double terrain protection our region enjoys.  To the east are the Rockies, with plenty of terrain rising to 8000 to 10,000 ft.  To the east of the Rockies are the Great Plains of the interior of our continent, which provides a flat, low-elevation conduit from the frigid, snow covered Arctic directly into the middle of the continent.

The Arctic is a particularly good place to generate cold air.   Covered with snow, which is a very effective emitter of infrared radiation to space.  Little solar radiation in winter.  Generally light winds and high pressure dominating.  

 Think of the Canadian Arctic and the nearby ice-covered ocean as the refrigerator for North America.

But to drive the air southward effectively you also need the right large scale wind flow, one that produces strong northerly (from the north) flow over the interior of the continent.

And we will have that in spades!

Take a look at the forecast upper-level (500-hPa pressure level, about 18,000 ft)  weather map for 4 PM PDT on Friday.  

Wow.  HUGE ridge (high pressure) over the West Coast, with a deep trough to the east of the Rockies.  The result of this highly disturbed upper level flow pattern is strong northerly flow pushing southward over the Great Plains

Now, let me show you a sequence of surface air temperature forecasts this week, which will allow you to view the invasion of cold into the hinterlands of North America.

Start with today at 1 PM.      The coldest air is found in the northern Canadian Arctic.

By Wednesday afternoon at 4 PM, the cold air is moving southward, with a notable extension into Alberta.  Note how the Rockies keep the cold air to the east!
By 4 AM Sunday, frigid air has plummeted through the Canadian plains into the northern plains of the U.S., with the Rockies providing protection for the western U.S.   Huge north-south extend of the cold air, with the source region in northern Canada. 

And by 4 AM Wednesday of next week the cold air moves eastward, into the upper mid-West and the northeast U.S. But we in the Northwest remain untouched!

Finally, to impress you with the temperature contrasts, here are the forecast temperatures for 10 PM Saturday.   36F in Seattle...which is cold for us, but -25 to -30 over Albert and as low as -11 in Montana. A four hours drive from Spokane (28F) to Great Falls, Montana (-10F) would be quite a shocker.

So if you don't get the cold air you grave during winter, you know one source of this warm affliction...the Rocky Mountains.

January 29, 2021

New Podcast: The Weekend Weather and the Most Dangerous Weather Phenomenon of the Northwest: Roadway Icing

 My latest podcast is out.   I start with a review of this weekend's weather, with isolated showers on Saturday and more frequent precipitation on Sunday. Perhaps a half-foot of snow in the mountains.

Then I turn to discussing the most dangerous weather feature of the region, the one that kills and injures more frequently than wind, floods, or anything else:  roadway icing.

A foggy situation of great danger!

I tell you what to look for and the foggy conditions that are most threatening.

Here is my podcast:
Click the play button to listen or use your favorite streaming service (see below)

You can stream my podcast from your favorite services:

January 28, 2021

The Blob is Weakening

 There are a lot of Blob enthusiasts in the Northwest and I wanted to provide an update on their favorite ocean/atmosphere feature.

The Blob, as many of you know, is an area of persistent above-normal temperatures in the northeast Pacific.    The Blob has substantial impact on western Washington weather, tending to increase daily minimum temperatures, sometimes by as much as 2-8 F.   The Blob also has implications for local marine life, including the northward movement of subtropical marine species.

If we take a look at sea surface temperature anomaly (difference from normal conditions or climatology) for last October, one can view a "healthy"  Blob off our coast, with portions 3-4 °C (6-8F) above normal,

But by mid-December, the Blob had weakened considerably (no more red colors), 

And by yesterday, it was quite anemic.  In fact, if you look closely, you will notice some blue colors (below-normal temperatures) along the West Coast and in the Gulf of Alaska.

Why is the Blob weakening?

 Blob's tend to develop when there is persistent high pressure...also known as ridging....over the northeast Pacific.   Such high pressure is associated with light winds, which minimizes vertical mixing in the upper ocean.  Mixing that brings colder water to the surface.   Thus, high pressure and light winds tend to produce warmer than normal temperatures......a Blob situation.

If we look back to mid-October through mid-November, there was, in fact, persistent high pressure over the northeast Pacific (see sea level pressure anomaly--difference from normal-- below).  Red colors indicate higher than normal pressure.

But during the last few months the situation has changed radically, with stormier than normal conditions over the same region (see pressure anomaly for last month below). Purple indicates lower than normal pressures, which suggests stormier than normal conditions.

No wonder the Blob is not doing well!

Consistent with a weakened BLOB, minimum temperatures at Sea Tac Airport have frequently dropped to normal minima, something that rarely happened in October (see blow below).  

January 27, 2021

Political Violence is Always Destructive: My August Blog Revisited

Violence begets violence… violence is a descending spiral begetting the very thing it seeks to
destroy, instead of diminishing evil, it multiplies it. –Dr. Martin Luther King

A little over six months ago, I wrote a blog calling out political violence in Seattle. This blog, Seattle: A City in Fear Can Be Restored, described the politically motivated violence on Seattle’s streets, its profoundly negative impact on the safety and lives of Seattle’s citizens, and noted the implicit support of the violence by local politicians.

It was based on one of the most obvious lessons of history: that political violence begets political violence and thus can undermine or destabilize democratic societies. The blog was motivated by my concern for the future of Seattle, which is seriously threatened by both street violence and its tolerance by our current city leadership. I was also worried that political violence in Seattle and other cities could damage U.S civil society, weaken our political system, stimulate violence by other groups, and further divide the nation.
May 30, 2020: Seattle

Tragically, this is exactly what happened.

My blog was never about Black Lives Matter or peaceful protesters, who have every right to bring their concerns to the attention of society.  It was about those who destroy and deface businesses, physically intimidate politicians and public servants like Police Chief Carmen Best, who set fires and physically attack onlookers and the press, and who believed physical violence is an appropriate tool to create the revolutionary change they want in society.

I paid a high price for writing that blog.

Within a day, my weather segment on public radio station KNKX was canceled by KNKX management, under pressure by political activists. Without any basis in facts, KNKX management claimed that my blog “delivered rhetoric that is offensive and inaccurate” and particularly noted my comparison of violent individuals to the brownshirts of the 1920s and 1930s. They did not study their history, and even worse, signaled their support for the worst of “cancel culture.”

And at the University of Washington, a group of student activists, who supported the violent agenda of the rioters, started a petition drive to get me ejected from the UW faculty. Diversity of viewpoint, freedom of speech, and the role of tenure for protecting university faculty was not their concern.

The 1930s’s Analog

KNKX management (Joey Cohn and Mat Martinez) claimed to be disturbed by the section of my blog that suggested that violence in Seattle was “reminiscent” of what happened in Nazi Germany during the 1930s. And my observation that the broken glass of the storefronts brought to mind Kristallnacht and other criminal acts.

This was not a casual analogy, but true to historical fact. The use of street violence by the Nazi stormtroopers (SS) was critical to Hitler’s gaining power. This violence and the counter-violence it provoked in communist and left-leaning groups undermined popular support for the Weimar democracy, leading people to wish for  a “strong hand” to restore order. Just as Kristallnacht was designed to send a political message of intimidation, so did the Seattle violence (and the violence in other cities). Political violence by street mobs also played a critical role in Fascist Italy, leading to the rise of Mussolini.

Importantly, many in the Seattle Jewish community contacted me with their support, including local rabbis and Regina Friedland, the Director of the Seattle American Jewish Committee (AJC). Vulnerable minority groups, such as Jews, know well from repeated experience that political violence frequently leads to attacks on their communities. Apparently, KNKX management considers themselves more knowledgeable than the AJC and a community that experienced Nazi violence firsthand.

We are letting political violence happen again

Most disturbing is that KNKX management and UW student activists deliberately distorted what I said, suggesting that I was comparing peaceful BLM protestors to Nazis, which is entirely false. Peaceful protests are a bulwark of our democracy and protected in the U.S. Constitution. In fact, the political violence undermined BLM and resulted in a loss of support for the movement. And political violence can only encourage violence from the opposite side of the political spectrum, which in fact occurred.

The Damage Becomes Real

The damage of the political violence in Seattle and other major cities was, if anything, worse that I had feared, not the least because it was tolerated—and sometimes encouraged-- by the local political establishment.

There was, of course, the tragic deaths in the “autonomous zone” that was allowed on Seattle’s Capitol Hill, including extensive damage to small and large businesses, with many in Seattle and other major cities being shuttered permanently from the destruction and the resulting fear.

Leadership in Seattle and other American cities have tolerated and even encouraged the violence, decriminalizing the destruction and not charging offenders who continue their violent actions without constraint. Many on the Seattle City Council were complicit in allowing the violence to continue, with Seattle City Attorney Pete Holmes effectively decriminalizing the criminal, violent activity. A city where violence is decriminalized is not viable. You can look at San Francisco to see our future.

A number of Seattle City Council members supported defunding Seattle Police by 50%, attempting to cripple the group responsible for public safety in minority and other communities. One Seattle Council member, Tammy Morales, PUBLICLY came out in support of violence:
"I don't want to hear is for our constituents to be told to be civil, not to be reactionary, to be told looting doesn't solve anything."

Council member Teresa Mosqueda said she “understood” the necessity of the violence:
“Colleagues, I hope we’re all saying we understand why that destruction happened”.

Seattle City Council

Public safety was damaged, with Seattle experiencing the highest murder rate in decades and lengthening of the time to respond to 911 calls. Many Seattle police officers have left for other municipalities. And who, not on the far left, would run for office in Seattle, knowing they would face intimidation and even physical attack on their homes and family?

Today it is obvious that the political violence by Antifa and others have little to do with equity for minorities; rather, supporters of violence are pushing a revolutionary agenda or reflecting simple criminal intent. How else do you explain the attack on the Democratic party headquarters in Portland, the destruction across Seattle last week, and the looting and vandalism in Tacoma this week, all after the accession to the oval office of Joe Biden?

This recent violence included the plundering of the original Starbucks at the Pike Street market
and the damage to small businesses, struggling to survive under COVID restrictions.

Perhaps most damaging of all is the normalization of political violence, which continued for over a half-year in Seattle, Portland, and other large cities. Such violence makes the population feel insecure and encourages opposition groups to take up violence as a tool.

As shown by the map below, provided by the Princeton ACLED U.S. Crisis Monitor, Seattle is second only to Portland for violent riots this year, with our destruction far exceeding larger cities such as Chicago and New York. An intolerable situation. And inexplicable that our political leaders have allowed it to continue.

Did six months of unconstrained destructive political violence encourage some Trump supporters to cross the line to the illegal invasion and desecration of the U.S. Capitol?

This is something suggested by a number of thoughtful analysts such as the NY Times writer Bret Stephens. And it is strongly supported by an examination of the Twitter feeds and Facebook pages of groups protesting/rioting in DC on January 6th , with repeated mentions of the summer violence in American cities as one of the reasons for their actions. Political violence leads to political violence.

And those who opposed Trump President should consider that the violence of the past six months was a lifeline for the erstwhile President and almost resulted in his winning a second term. Fox News and other conservative media outlets played up the violence non-stop for months (with special attention to Seattle’s CHAZ zone and “summer of love” and the continuous Portland war zone) and Trump repeatedly mentioned the violence as a reason why his administration must remain in office. Antifa and others participating in political violence were Trump’s most potent allies. So was the Seattle City Council.

In short, if anything, my August 5 blog under-warned about the implications and dangers of the
political violence tolerated in Seattle and other American cities.

The bottom line: Political violence should never be allowed or tolerated.  Never.

Politicians who make excuses for such violence and facilitate its expression should be voted out of office. The effective decriminalization of political violence should be ended, with offenders facing real consequences.

One of the great lessons of history is that civilization and “civil society” is actually a thin veneer and highly fragile. Political violence is the surest way to weaken the bonds between fellow citizens, to provoke mistrust, fear, and hate, and to undermine the institutions we depend upon for our safety and ability to function.

Thus, those supporting or tolerating political violence have undermined both the safety and future of our city and nation for misguided, short-term political goals. 

They will not be looked upon favorably by posterity.

January 26, 2021

Dry Snow-Eater Winds over Puget Sound

 The winds are really blowing right now in central Puget Sound but are from an unusual direction:  easterly (from the east).

Looking at the infrared satellite image for 5 PM today, you would expect lots of precipitation reaching the surface over western Washington, but only a few sprinkles have hit from Everett to Tacoma.

This lack of precipitation i confirmed by the radar image at that time (see below).  And it was even precipitating and SNOWING on the coast.  How weird is that?  In fact, it IS snowing above us right now, but the snowflakes are evaporating before they reach the surface.  They don't have a chance.

The explanation is the easterly flow, produced by a strong low-pressure center off our coast (see weather map at 4 PM below).  With high pressure inland and low pressure offshore, a powerful offshore directed pressure difference is in place, producing strong easterly winds.

How strong?  Here is the plot of wind direction and gusts (red numbers) around the region (click on image to expand).  Some locations are gusting to 40-50 mph.

And since strong easterly winds are less frequent than powerful southerly winds, some branches are falling producing scattered power outages (see PSE outage map below).

But the most interesting aspect of the winds is their dryness.  Dry because they are associated with air that is SINKING and warming on the western slopes of the Cascades.  

To illustrate, consider the conditions on the top of my building at the UW (below).  

Around 1 PM (21z at the bottom), the winds started to pick up (see letter A), with gusts to 25 knots!  Wind direction was due east (second panel).   

The third panel is the interesting one...the top (black) line is temperature and the bottom is dew point (a measure of moisture).  Temperature rose, but dew point fell (letter B).  The bigger the difference between the two, the drier the air.

Take a look at the fourth panel that shows relative humidity.  Mama Mia!  Relative humidity plummeted from around 80% to under 50%.  Dry air.  No wonder I got a shock when I touched a door knob.

The weather system offshore and the associated front (apparent in the satellite picture) are producing lots of snowflakes and ice crystals aloft.  But they are sublimating (what evaporation from ice is called) and disappearing before they reach the surface.

Sometimes, this kind of downslope wind is called a Chinook (or snow-eater) wind.

It is certainly having a feast with the snow above us right now.

January 25, 2021

The Wednesday Snow Event Will Be On the "Wrong" Side of Our Mountains Plus the Upcoming California Deluge

 More snow is coming to our region late Tuesday and Wednesday, but Seattle snow lovers will be disappointed if they hope for snow in their backyards.  

Substantial snow will be very close, but on the eastern sides of local terrain.  And the upcoming storm system will rapidly push southward, bringing welcome, heavy precipitation to drought-stricken California.

The key feature is an approaching low pressure system, as shown by the forecast for Tuesday morning at 10 AM

This offshore low, combined with high pressure inland, will create a large east-west pressure difference that will drive strong easterly (from the east) winds at low levels. And instead of moving eastward into Washington, the low will push southward towards California.

The result of the easterly flow will be upslope flow and bountiful precipitation on the eastern sides of the Cascades, Olympics, and other region terrain features--the opposite of normal.   In contrast, the normally wet western slopes will be in the rainshadow (or snow shadow) of local mountains.

Consider the latest forecast of the UW super-high resolution WRF model, with the accumulated snowfall through 10 AM Thursday shown below.  The southeast side of the Olympics and parts of Kitsap will see snow, as will the eastern slopes of the Cascades.  But look how dry the western slopes of the Cascades will be as well as the lowlands from Everett to Olympia.  Same for Portland.

Looking at the big big picture, a very deep trough of low pressure will develop over the eastern Pacific with storm systems heading southward, deep over California (see upper level map for 10 PM Thursday).  

The precipitation totals in California will be extraordinary, with the amounts through Friday morning shown below.  We are talking about 6-7 inches along the central coast and in the Sierra Nevada, with substantial amounts from San Diego to the northern border.

Considering the substantial precipitation deficit of this water year so far (see the figure below that shows how far behind they are), California will still need more water, but this one period will go a long way in mitigating the drought, particularly for the southern half of the state.

And he snowfall will be bountiful in the Sierra Nevada, with an extensive area getting as much as 4 feet.  Good skiing is ahead and a snowpack that will help provide water this spring and summer.

January 24, 2021

A Mini-Hurricane Hits the Washington Coast

The imagery from the Langley Hill radar near Hoquiam was quite extraordinary this morning.  

At 10:10 AM there was a clear, precipitation-free "eye" with heavy precipitation bands circling around it as the feature came ashore near the the northern tip of the Long Beach peninsula.

If it wasn't for the scale, would be wondering whether we were looking at the Gulf Coast in September!  And a close look a few minutes later showed the "eye" sliding eastward just south of Westport.

This little "hurricane" packed some wallop, with eye associated with a small, intense  low pressure center and strong winds.

Consider the situation at Toke Point (see map), where winds gusted to 40 knots (47 mph) at 1036 AM, dropped to 11 knots in the "eye" and rebounded  to 17 knots on the other side (see plot below).

The sea level pressure plummeted to 1004 hPa (29.65 inches of mercury) at the center of the low.

A surface map at 9 AM, shows the mini-low ready to move inland, with a pressure of 1004.7 hPa and rapid pressure falls at buoy 46099.

The mini-low was not very apparent in satellite imagery at 10:30 AM (see below) and was not well forecast by high resolution modelings systems such as the UW WRF model or the NWS HRRR modeling system.  For example, the UW 

 modeling system initialized at4 PM on Saturday, had two lows, with none in the right place (see below).  Hard to get such small-scale features correct coming off the relatively data poor lower atmosphere of the Pacific.

But one thing is sure:  this event clearly demonstrated the value of having a coastal radar, which can document small scale features that are not apparent even in the best satellite data.  The Oregon coast, which has essentially no radar coverage for its southern half, desperately needs a coastal radar.  

Senator Cantwell helped secure a coastal radar for Washington; an Oregon Senator needs to step up to the plate.

January 22, 2021

New Podcast: Weekend Forecast, Snow Update, and a Look at Western Washington Snowstorms

My new podcast is online (see below or the upper right to listen) and on it I examine the chances of snow this week and give you a short tutorial on western Washington snowstorms:  why are they so rare and what does it take to get decent snow west of the Cascades.

Skies are clearing right now and expect sun and mid-40s the rest of the day.

Tomorrow morning will be quite cold, with clear skies overnight allowing the Earth to radiate heat to space.  With a moist surface, we expect some fog and real threat of dangerous freezing fog.

Sunday morning will bring some snowflakes to western WA but mainly above 500 ft. 

Let me show you an interesting graphic that shows BOTH rain and snow.  Rain is shown by gray shades and snowfall by colors.

For the 3 hours ending 4 AM Sunday, just rain over the lowlands, with snow up on the slopes.

For the next three hours (through 7 AM Sunday), light snow on the hills and high elevation areas (such as north of Seattle to Everett, Cougar Mountain, southwest of Olympia, southwest WA)

And the light snow continues for the next three hours in those areas.  And then it is over!

We just don't have sufficiently cold air over us.  Another chance on Tuesday/Wednesday.

Here is my podcast:
Click the play button to listen or use your favorite streaming service (see below)

You can stream my podcast from your favorite services:

The Weather Regimes of Summer

 Weather patterns tend to get "stuck" for extended periods and we have certainly seen such persistent conditions this summer.    W...