Tuesday, July 25, 2017

Major Dry-Day Records May Be Broken

As July approaches its end, it is becoming increasingly likely that Seattle and other northwest locations may break some major records regarding lack of rain:

1.   In Seattle, the first July without a trace of rain and the driest July on record.
2.   The longest run of days without measurable precipitation in Seattle.  (measurable rain means at least .01 inch of rain).  The current record is 51 days and today we have gotten through 38 dry days in a row.

The last month has been quite dry....but it is important to note that this IS the driest time of the year in the Northwest and we are one of driest places in the country during midsummer.  To illustrate the situation, here is the percent of average precipitation for the past month (6/24-7/23).  Much of the western U.S., including western Washington, Oregon, and California,t has received less than 2% of the normal amounts.

Now this sounds very scary, but it really isn't as extreme and impactful as you might think, considering we are now in the West Coast dry season, which enjoys a Mediterranean Climate (wet winter, dry summer).   To illustrate, here is the difference of the precipitation of the past month from normal (climatology).  Most of California and Oregon are less than an inch drier than normal.   Western Washington is the most anomalous, with 1-2 inches below normal.

The origin of our dry period is fairly clear:  persistent high pressure over the West Coast, something illustrated by this graph, which shows the difference from normal of recent upper atmosphere (500 hPa) heights (green/yellow signifies above average).

We are not only dry, but are entering the driest time of the year, as illustrated from this plot of the probability of .01 inch of precipitation in a day.

So what is the forecast?

 Let's start with the best extended predictions:  the 24h precipitation forecasts of the European Center ensemble of 51 forecasts out to 9 August.  The top panel shows the individual precipitation forecasts, with most showing nothing through the end of the month, with only about half showing very light rain during early August.  The bottom panel shows the ensemble mean (or average), which is typically a very good forecast.   

The bottom line:   the July record looks probable and we have a good chance and beating the 51 day record.

To get another view of forecasts, here is the output of the NAEFS ensemble--a combination of the U.S. and Canadian ensemble forecasts--through August 8.  The second panel shows precipitation forecasts (in mm).  Dry though July and a small chance of very light precipitation after August 4th.

More support of us having a real shot at the 51 day consecutive dry-day record.

One interesting issue:  the dry weather has been associated with very little lightning, resulting in only a modest number of wildfires so far.  

Sunday, July 23, 2017

Personal Fireworks Should Be Banned

In a blog on July 5th,  I asked whether personal fireworks should be banned, noting the huge array of negative impacts.

There was a lot support for doing so, and some of the emails and calls I received were disturbing and emotional.

Two combat veterans called, describing their terror from the concussive sounds in the night.  They told me they were not alone.

I heard from a woman who lost her dog, who had been shaking from fear and hiding in a closet beforehand.

I got an emotional call from a woman whose mother was dying of Alzheimers and was in terror of the explosions, unable to understand their cause.

And I am tired of reading stories of maimed children, destroyed homes, and even a father killed in front of his kids--all due to fireworks.

On July 5th, I was walking my dog at Seattle's Magnuson Park when some teenagers started shooting off rockets in the kite hill parking lot, almost hitting a mother and her kids.

Folks, it is time to end this madness, to make personal fireworks illegal, to seriously enforce this ban, and to leave the pyrotechnics to community displays run by professionals.

The historical perspective

John Adams, in a letter to his wife Abigail, suggested that independence should bring great celebrations "solemnized with Pomp and Parade, with Shews, Games, Sports, Guns, Bells, Bonfires and Illuminations from one End of this Continent to the other..."

And he was not disappointed.  Americans celebrated their independence with large bonfires, cannonade, and volleys from a variety of firearms, with nearly all the action limited to communal celebrations.

The 19th century brought expansion of the celebrations, including increased use of individual fireworks and firearm use.  As a result, the there was a huge expansion of death, injury, and damage, so much so that the American Medical Association and  insurance companies, among others, pushed for restriction of personal displays and more stress on public fireworks and patriotic gatherings. Major restrictions on personal fireworks, fires, and small arms fire was put in place during the early 20th century, and the reductions in deaths and injuries were stunning (see below).   From 466 killed in 1903 to 20 dead in 1912.   

In the 1930s, the Depression resulted in a reduction of public displays and the use of personal fireworks increased.   By the 1950s and early 1960s, increased firework use and a much larger population resulted in a rapid increase in injuries and fires.  The result was a movement towards "safe and sane" fireworks, with smaller explosive charges and restrictions by a number of states.

Recently, there has been a surge in fireworks use, with several states dropping restrictions and a massive increase in imports from China.    Furthermore, "improvements" resulted in louder explosions.     An issue has been the loss of control of fireworks sales in several states and the availability of less "sane" explosives due to unrestricted sales occurring at Native American "boom cities."


I put it to you--is it patriotic to explode loud personal fireworks, when they terrorize or discomfort our combat veterans...the individuals to whom we owe so much?  I don't think so.

Is it patriotic to purchase a product from a foreign nation (China) that pollutes our air, injures at least 10,000 of our citizens a year, burns down thousand of homes or buildings, and sets aflame vast areas of our nation?   In another time, this might be considered an act of war.  In fact, the Japanese tried to do this during WWII using balloon bombs.

Let's be honest, most folks are not shooting off fireworks due to patriotic fervor but rather thrill seeking and entertainment.

Injuries and deaths

Official government statistics indicate that about 10,000 citizens end up at the emergency rooms from fireworks-related injuries, and this is surely undercounting the numbers affected.  Typically, there are around a dozen deaths and hundreds of terrible injuries, including loss of eyesight and blown off fingers or hands. Thousands are burned.  The overwhelming majority of injuries are to young people (see figure below), with 40% of the injuries affecting children of 14 and under.
Non-enforcement and disrespect for the Law

Currently, personal fireworks are banned in a number of Washington State cities, such as Seattle and Bellevue.  But police are not enforcing the ban and if they do catch someone, they just confiscate the fireworks.   Here is a quote (from an article in the Stranger):

Enforcement of firework use is difficult. In order for the Seattle Police Department to give out a citation, they pretty much have to witness someone “holding a match to a firework,” says SPD Detective Patrick Michaud.
“So it becomes extremely difficult for us to get out there and respond in time,” Michaud said, adding that SPD might be able to catch someone lighting up “if we’re lucky.”

Just amazing.

Can you imagine any criminal activity that is EASIER to locate than setting off fireworks?  Big booms, bright lights, screaming sounds and rocket bursts in the air?   How many bank robbers would be caught if they blared loud sounds and bright lights when they were making their heists?   The police are deliberately not enforcing the law and thousand of folks are breaking the law and no one seems to care....this is not a good civics lesson.  It teaches disrespect for the rule of law and cynicism about law enforcement.

I am not suggesting that the police send an army out there and arrest hundreds of people.  But making a clear statement that the law would be enforced, followed by a few hundred citations with a substantial financial penalty would sober folks up rapidly.


What day has more wildfires initiated than any other?    You guessed it...July 4th (see figure below).

According to government statistics, thousands of fires are caused by fireworks each year, involving hundreds of thousands of acres.  Probably not what John Adams was hoping for.

Air pollution

Fireworks seriously pollute the air, endangering folks with lung and heart issues.  In some areas of our state, air quality declines to Beijing levels on the evening of the 4th and July 5th.  Here is a plot of the amount of small particles (the kind that go deep into your lungs) for Tacoma over the past month.  HUGE July 4/5 spike.   Very unhealthy.  Fireworks can and have triggered serious asthma attacks.

I had an interesting conversation with a friend at the Puget Sound Clean Air Agency.   He felt that personal fireworks were much more of a problem for surface air quality.  First, there is more personal fireworks (in terms of amount of material exploded) and personal fireworks are set off at/near the ground, in contrast to the big public displays that send their projectiles high into the air.  And the degradation starts before the official fireworks. Thus, personal fireworks are the main origin of air degradation.  And particles are not the only issue--many fireworks are laced with heavy metals and dangerous chemical (e.g.,  perchlorate).

Terrifying our pets and animal friends

What day of the year do you think the greatest number of pets run away and are lost?  July 4th.  I have had dogs and cats and when the explosions start, their terror and fear are obvious.

So what should be done?

It is time to deal with personal fireworks.   And in my mind, a statewide ban is the best approach. 

 One starts with forbidding sales and use on all non-tribal lands.  And then we ask our native american friends to stop sales on all tribal lands.  Protecting the environment and the land is deeply embedded in native american culture and values.  Surely selling devices that burn our forests and rangelands, pollutes our air, and degrades our waterways (with all the plastics and fireworks-related chemicals) is something they would want to stop.   If not, we could express our displeasure by avoiding their casinos.

Some states have been highly creative in dealing with fireworks.  For example, Hawaii passed a law requiring a license and was only available to adults.   Fireworks use collapsed.

Perhaps one of our political leaders would be willing to take this on.   If not, a community-based group could be formed to lobby the legislature or even or push for an initiative.  There are a lot of environmentally concerned folks in our area....perhaps they will consider giving this issue some priority.

Addendum:  Personal Freedom

Several folks opposed a fireworks ban based on the idea of personal freedom.   But there is a difference of a vice that harms only you and one that hurts others.  Fireworks hurt others.  The pollution hurts others.  The fires it causes burns others homes down.  The noise hurts the weak and traumatized.  Etc.   Freedom is important, but one does not have the freedom to harm others.  Smoking is legal, but you can not smoke in a public place where others will be harmed.

And should minors have the "freedom" to purchase and use fireworks?   We deny a 12-year old the freedom to drive a car...that is ok.  Because minors don't have the judgement yet for dealing with the responsibilities and consequences of their actions.   But it is fine for them to use fireworks that can destroy theirs or others lives?

Thursday, July 20, 2017

What are these clouds?

I received nearly a dozen emails with pictures from folks interested in the clouds apparent around 5-7 PM last night (Wednesday).  Some examples:

Picture courtesy of Nancy Flowers

Picture courtesy of Dyana Stevens

Seattle PanoCam 6PM

What was going on?  Yesterday, a weak front was approaching and this feature was associated with an upper level trough coming off the Pacific (see 500 hPa--around 18,000 ft--map at 5 PM Wednesday).  Such an upper trough causes

upward motion that can promote clouds and instability in the middle troposphere).  In fact,  the vertical sounding at Quillayute, on the WA coast, at 5 PM Wednesday, shows a nearly saturated layer between roughly 500 and 300 hPa (roughly 18,000 ft to 30,000 ft).

As a result, some altocumulus clouds (middle level puffy instability clouds) formed and were vigorous enough to start precipitating out ice crystals.   The long tails of precipitating ice are called fallstreaks or mares tails.   They get distorted and curved by the change of wind with height (wind shear).

So the bottom line is:  folks saw precipitating altocumulus clouds forced by an approaching upper level trough.

Finally, if you want to see an absolutely stunning weather video dealing with clouds and precipitation in Arizona, check this out.   Heroic music, gorgeous imagery....it may bring tears to your eyes.

The Weather of Arizona - A Time Lapse Film from Bryan Snider Photography on Vimeo.

Tuesday, July 18, 2017

Smoky British Columbia and Will Wildfire Smoke Affect Eclipse Viewing?

After a recent bout of lightning, a number of major fires were initiated over British Columbia.  As shown by the NASA MODIS satellite imagery over the past three days (see below), the smoke plume have been impressive.

Wildfire/smoke season has begun over the Pacific Northwest, with most of the smoke so far heading eastward.

But the question of many is whether smoke will be a factor during the August 21st eclipse.   There is a lot of talk of folks converging around Madras, Oregon, east of the Cascade crest, but is there a downside to that location: smoke?

To get some insight into this question, here is the climatological probability of a significant wildfire s created by the NOAA/NWS storm prediction center.  A fairly significant chance (10-20%) for a wildfire being around on August 21st around NE Oregon, including the Madras area.

And to illustrate the threat, here is a MODIS image for August 22, 2015, showing a wildfire that spread smoke over the area.

Now smoke will not take out the sun, but it could seriously degrade viewing of the corona and solar prominences.   The lack of rain of the past month is progressively ratcheting up the fire risk for later in the season.   Something to watch.

Announcement:  Atmospheric Sciences 101

I will be teaching Atmospheric Sciences 101 this fall if anyone is interested either as a UW student or the Access Program for those over 60.  This is a general intro to weather and weather prediction.  MTWTh 10:30-11:20, Kane Hall.

Monday, July 17, 2017

Melt Out at Paradise on Mount Rainier

Yesterday, July 16th was melt-out day at the official snow measuring site at Mount Rainier.

Located at roughly 5500 ft, this melt-out day is about 1 week later than typical for the past 100 years (information from Mark Albright, UW Research Scientist).  Here is an interesting table showing the mean melt-out dates by decade at Paradise Mt Rainier:

Decade     Date     No. of Years
1910s       16 July     2*
1920s       10 July      9**
1930s        3 July       10
1940s        1 July       10
1950s        17 July       9**
1960s        5 July        10
1970s         21 July      10
1980s        10 July       10
1990s        15 July       10
2000s        10 July        10
2010s         1​6 July      8***

* 1917 and 1918, ** 1925 missing, 1950 missing, *** 2010-2017

As you can see, there is no real trend towards earlier melt-out, which would be a sign of global warming.  That will come, but later in the century.

What about a much lower site?  Such as Stevens Pass (about 4000 ft above sea level)

The snowpack melted out this year on 7 June 2017 at the Stevens Pass SNOTEL site, with the melt-out this year tied for ​11th ​latest out of the past 37 years (the length of record there).

Mean melt-out dates by decade showing a trend towards later melt-out of the snowpack in recent years:

1980s: 30 May
1990s: 1 June
2000s: 2 June
2010s: ​4 June (thru 2017)

Similar to Paradise, the snowpack is holding on later into the warm season.  

 The maintenance of our snowpack into the summer helps maintain our streamflow into the summer, which is good for fish and water resources.   By the middle of the century we expect the situation to change as warming causes more of our precipitation to fall as rain in the mountains.

Saturday, July 15, 2017

How Western Washington's Temperatures are Controlled By the Pacific Ocean

Have you ever thought about how boring and relatively unchanging our high  and low temperatures are?  Particularly, when we are in our normal situation with modest onshore (westerly) flow?

To illustrate, here are the temperatures at Seattle Tacoma Airport for the last two weeks (red lines), with the typical highs and lows.   We had a warm spell (6th and 7th, highs around 85F) when we had a bit of offshore flow, but most days reach their max between 70 and 80F, with the long-term average in the low to mid 70s.  The low temperatures are MUCH more uniform--roughly 53-58F.
In contrast, a location like New York City, also on a coast, has huge variations, with the low temperatures ranging from 80F to the upper 60s.  So why are we different?
The answer is the Pacific Ocean and the typical onshore flow at low levels during our summer.

During the summer, high pressure is typically resident over the eastern Pacific Ocean, with lower pressure inland, resulting in gentle onshore flow at low levels (see example for Monday, July 10 at 5 AM).

So the air reaching Seattle and western Washington had been over the Pacific Ocean for a long time, with the air near the surface taking on the temperatures of the ocean surface.

So what are the ocean temperatures off our coast right now?  Here they are (below).  Roughly 14-16C (57-61F), with some colder water from upwelling (water coming up from below) right near the coast, and a bit colder water offshore.  So roughly the upper 50s.  This is the kind of air that is flooding our region at night, without solar radiation to warm it up.  During our short (and generally clear) nights, there is radiational cooling from the surface, so that can take off a few degrees.
Not only are our temperatures relatively uniform, but so is the humidity or moisture content.  Our air can't pick up much moisture over the water because it is relatively cold...a very different story than that warm Gulf of Mexico.  Thus, our  dew points (the temperature you must cool air to get saturation) are typically no more than the lower 50sF during the summer.  That is important, because high dew points can keep the temperatures up at night (like in the humid East Coast).

So there is no real mystery what our temperatures typically drop into mid to upper 50s at night...and do so in a very reliable way.  It is the Pacific and its modest temperatures.

But why do we have highs in the 70s during the day when we have onshore flow and relatively clear skies, like the last few weeks?

Yes, it is the Pacific again.    We start off with a water temperature of say 57F (14C), with the nearby air of similar temperature.   Over the ocean, without surface heating, the lower atmosphere is relatively stable, with only a small change of temperature with height.  With high pressure dominating the eastern Pacific, there is sinking air in the middle to lower troposphere, which weakens towards the surface.  Such sinking tends to produce stable conditions and often inversions (temperatures increasing with height).

The temperature sounding Friday morning at Quillayute on the Washington Coast illustrates this.  Red line is temperature and heights are in pressure (700 is about 10,000 ft).  Click on the image to expand.

The typical lapse rate (change of temperature with height) along the coast at the radiosonde site at Quillayute  during the summer is roughly 3.5C per km (the graph is from the sounding climatology page of the NOAA Storm Prediction Center). The black line are the average values.

So if the temperature at surface is 15C, the temperature at 1.5 km (about 850 hPa) is roughly 5.25 C less. Let's call it 10C.  That air blows in over Seattle and western WA.

Now why do I care about 1.5 km and 850 hPa?

Because during the day over land, surface heating causes the air to mix in the vertical and it usually reaches that height.  That mixing is associated with a lapse rate (the adiabatic lapse rate) of  9.8C per km.   To put it another way, air coming in over the ocean can be mixed down to the surface, where it is warmed by compression by 9.8C per km.  Or to say it differently, the air is warmed by roughly 15C as it descends 1.5 km to the surface.  If the air started at 10C, it would be 25C at sea level.   25C is 77 F!  Our typical high temperature during the middle of the summer.

I know this explanation is a bit complicated.

But the bottom line is that we have the sea surface temperature offshore driving the surface air temperature over the ocean.  That is connected with temperatures of air in the lower atmosphere that moves inland, which can mix to the surface during the day.  The result is a direct connection between the temperature of the sea surface of the eastern Pacific and our high temperatures.  At night, when vertical mixing is minimal the connection is more direct, with low level air just moving in horizontally.

Offshore flow changes everything... our temperatures become disconnected from the slowly changing ocean temperatures, and we can get much more extreme temperature variation. So thank the ocean for our perfect summer temperatures.  And it is this connection with the ocean that will slow the impacts of global warming over our region, giving us more time to deal with that issue.

Thursday, July 13, 2017

Will You Get Free Windows on August 6?

Nearly every day lately there is a huge color advertisement in the Seattle Times offering FREE WINDOWS for your home if the temperatures reaches 89F on Seafair Sunday (August 6th).  Here is an example:

Several people have asked my take on it...so here it is.   I emailed the advertiser to get the exact rules.   IF you have already ordered windows from them and the temperature reaches or exceeds 89F at Seattle Tacoma Airport on August 6th, the windows will be free.

So, what are the chances you can win big on those new triple-pane beauties?  Is this a good bet?  Let's check the climatology at Seattle-Tacoma Airport, where data is available from 1948 to now.   Thus, we have 69 years to look at.

It turns out that maximum temperature reached 89F or more at Sea-Tac  ONLY ONCE during that period--91F in 1972.  

So based on the climatology of Sea-Tac, there is only a 1.4% chance of securing those free windows.    The odds look awfully good for the "house."  

Some of you might argue, that global warming might be helpful in winning this bet and that climatology might be giving us an underestimate of the probability of getting to the magic 89F.  Good point.

Looking at several regional stations, the warming trend over the period was about 1F.  Not enough to make a huge difference.  Make it a 2% chance.

It appears that the odds provided by our friends in the window industry would make casino operators blush.

Typical chances of winning at blackjack is 46%.

Roulette?  Pick a single number and your chances are 1 in 37 or 2.7%.  Much better than the odds given by the window folks.  So buy the windows if you need them (I could use some myself), but don't expect to get free ones.

Now if already signed up for deal and were thinking of giving the Sea-Tac thermometers a little "help", keep in mind that the sensors are between the runways at the airport, and there is probably little chance of bribing the National Weather Service technicians who calibrate the thermometers.  Call me if you want their telephone numbers.

Tuesday, July 11, 2017

New Study Suggests Global Warming Will Be Kind to the Northwest: But There Will Still Be Impacts

A recent study published in Science Magazine by Solomon Hsiang and others completed an economic analysis of the economic effects of global warming by the end of the century (2080-2099). They considered a range of impacts, including agricultural, property and violent crime, mortality, and coastal issues (sea level rise, storms), among others.  Doing so, they created a map of total economic damage, shown below (in percent of Gross Domestic Product, GDP).  Red and orange colors signify global warming will cause damage, while green colors indicated that global warming will be an economic plus.  They drove their economic models with output from climate simulations.

The bottom line is that cool states come out ahead, while warmer locations are hurt by global warming. Not good for the southeast states (particularly Florida and Texas) and most of Arizona.  But generally quite good for the Pacific Northwest.   Only a thin strip on the eastern slopes of the Cascades has a slight negative impact and the coastal zone does quite well. 
Hsiang et. al, 2017 Science Magazine

You can see some of the component contributors below.  For our region, big gains in agriculture from the added warmth.  Large drops in mortality (cold is a killer).  Far less energy costs for heating.  No increase in coastal damage because our land is generally well above sea level.

Hsiang et. al, 2017 Science Magazine

It is interesting to compare the Hsiang et al economic analysis with one examining meteorological threats from global warming  found in one of my earlier blogs (see below).  Each color represents a different threat (e.g, red would be storm surge from hurricanes).  The white area indicates one area of little increase in threat:  the Pacific Northwest.

So the Northwest is an area that should do particularly well under global warming-- we will have plenty of rain, a bit of warming will be welcome over much of the area, our storms should not become more severe, and sea level rise is not much of a problem.  Hsiang et al suggests we will come out ahead economically.    

But I am not sure that paper considers all the costs.  Warming will bring less snowpack in the mountains as the freezing level rises, so less snow melt available in the summer.  Thus, we will have to either learn to be more efficient with water (e.g., more drip irrigation in eastern Washington) or build expensive dams and reservoirs (costing billions of dollars).

Although the total precipitation will not change dramatically (small increase), we do expect the heaviest events to bring 30-40% more rain...and thus more flooding.  Thus, we will need to move folks away from rivers, something that could easily cost billions more. And away from steep slopes (like Oso).

Our east-side forests are in terrible shape due to fire suppression and poor forest practices (clear cutting rather than thinning, leaving slash, etc).  As a result, we have seen increasing number of large, intense fires, and local warming will make this worse.   We thus need to spend billions more to restore our forests to better shape to prepare.

So global warming will cost us in these and other ways; as a result, the benefits of lower heating bills, less ice/snow on the roadways, and enhanced agriculture will be balanced in part by steps needed for adaptation.

Global warming will probably end up being a wash for us.  But this will not be true of those living in warmer sections of the U.S., and for much of world's population that lives in he subtropics (such as India, SE Asia, Africa's Sahel, and Mexico).  Thus, the moral imperative is for us to reduce our carbon emissions, while at the same time building the climate resilience of the region.

Atmospheric Sciences 101:    I will be teaching the introductory weather class this autumn (10:30 AM, Kane Hall, UW).   Open to UW students and the community (and inexpensive to audit if you are over 60 through the UW Access Program).

Friday, July 7, 2017

A Very Dry Start to Summer

For much of the Northwest, it hasn't rained since mid-June, when we had an unusually heavy one-day deluge of over an inch (see accumulated precipitation at Seattle Tacoma Airport over the past four week, red is observed, blue is normal).  Interestingly, because of that one-day amount, the last four weeks had nearly normal rainfall!
A map of the total precipitation over the past two weeks shows less than .1 inches over most of the western U.S., with most locations getting nothing.

The departure from normal shows .75 to roughly 2 inches below normal over western Washington.  The departures from normal are not large because we get very little precipitation this time of the year.
In fact, we are now entering the driest time of the year in the Northwest, with the lowest precipitation amounts the last week of July and first week of August (see climatology for Seattle)

 The models are forecasting little or no precipitation for the next few weeks.
For example, the 21-member NOAA/NWS GEFS ensemble (many forecasts made to explore uncertainty) show virtually nothing for the next 192 hours.

 The even larger NAEFS (US plus Canadian) ensemble shows the same thing  through the 21st (second panel)
 And the larger European Center ensemble indicates no precipitation or a few hundredths (gray colors) during the next ten days.  The bottom panel is the ensemble average... maybe a slight misting on Monday.

With above normal temperatures and no rain, the demand for water in Seattle has increased substantially (see Seattle SPU graphic)--see the red line.

This year has certainly been one of contrasts:  the wettest winter for many and now a very dry early summer.