Sunday, April 23, 2017

Pacific Mega Moisture Plume Approaches the West Coast

It is the JAWS of Pacific moisture plumes.  And it is now reaching our shores.

Today's satellite imagery is stunning... a wide plume of moisture stretching across the entire Pacific Ocean and headed for the Pacific Northwest.  Let me show you.

First, a visible satellite image --what you would see from space--showing a continuous band of clouds, 1000 miles wide, stretching from the western Pacific to just off our coast. Scary.


Next, an infrared image, which shows the temperature of the clouds (or surface), with white indicating high/cold clouds.  Similar thing.


Or an image from the water vapor channel, showing the emission of radiation from water vapor.  Even more impressive, with clear evidence that some of the water vapor plume has reached our coast.


We can also measure wave vapor using the microwave part of the spectrum, and here is a global viewpoint from that wavelength.  The moisture plume  (at 11 AM Sunday morning) can be traced all the way back to the northern Philippines, 6600 miles away!  Moisture from the subtropics and tropics is coming to us!

As I noted in my previous blog, this is a relatively unusual situation for late April and ground zero for landfall of this moisture will be the Oregon coast. As it rises over NW terrain, substantial precipitation will be observed.  For example, the 72h total precipitation ending at 5 PM Wednesday, brings 2-5 inches over the Oregon Cascades and the coastal mountains.  Importantly, northern CA gets heavy precipitation, which is quite rare in late April.

The latest European Center forecast for total precipitation through Thursday AM shows a very wet Pacific Northwest.

You really want to get depressed?  Here is a count of the number of days with precipitation over the past 30 days.  Western Washington is a sunless disaster area.

The complaints about this winter's clouds and rain have been deafening;  perhaps it was contribute to large migration back to California and relieve the housing situation in the Puget Sound region.   I was wondering why traffic has been greater southbound on I5...perhaps our weather is coming to our rescue, sending the high-tech hordes back to the sun-drenched Bay area.



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How will Northwest Weather Change Under Global Warming?  Help Us Determine the Local Impacts of Climate Change

Society needs to know the regional impacts of climate change and several of us at the UW are trying to provide this information with state-of-the-art high resolution climate modeling.  With Federal funding unavailable, we are experimenting with a community funding to build this effort.  If you want more information or are interested in helping, please go here.  The full link is: https://uw.useed.net/projects/822/home    All contributions to the UW are tax deductible.

Saturday, April 22, 2017

A Late April Precipitation Pattern I Have Never Seen Before

The model precipitation forecasts for the next few days is extraordinarily unusual for late April, with some aspects unique for any time of the year.

We are talking about an amazingly long and wide precipitation/moisture band coming from the west that will bring record amounts to some locations from northern CA to southern WA.

Let me show you what I mean and be prepared to be impressed.   I will start with the 24h precipitation ending 4 AM Monday from the UW WRF model (relatively coarse outer domain).  I have never seen anything like this:  a very wide band of precipitation stretching thousands of miles due east into the Pacific.  The width of the precipitation band is extremely unusual (very wide).

 Next, zooming in to the higher-resolution (12-km) domain for the 24h precipitation ending 5 PM Monday, one views a very wide precipitation band that is enhanced as it is forced to rise by the terrain in western Oregon and northern CA (1.28-2.56 inches indicated by the pink colors).  I have been looking at these model runs for decades and have never seen anything like it.

Or how about the cumulative precipitation through Tuesday at 5 PM from the vaunted European Center model?  The huge precipitation band is shown, with 2-3 inches from the Olympics to northern California.   Want dry conditions?  Head to the Columbia Basin.

To get an idea of how unusual this amount is, here is the % of normal for the above precipitation totals.  Some locations are 400% of normal.  But it is the north-south extend of the precipitation that really impresses me.

The moisture coming into the Northwest is from a zonal (east-west) atmospheric river.   During the winter, the most significant atmospheric rivers come from the southwest, but they tend to become more east-west during spring.  One measure of an atmospheric river is the vertically integrated water vapor graphic, that shows the total moisture in a vertical moisture in a vertical column of air.   The WRF forecast for 11 PM Sunday shows the high values (blue and reds) heading right towards the CA/OR border.
A forecast of atmospheric water vapor for 8 AM Monday shows the extraordinary east-west extend of the the water vapor plume, which originates over the southwest North Pacific.

You can see the ejection of the moisture from the tropics into the midlatitudes in this animation, which show the distribution of water vapor during the past few days (click on image if it doesn't animate).  So the substantial rainfall we will be experiencing can be traced back, in part, from moisture starting over the Philippines.

The depressing fact:  here in the Pacific Northwest we are living through a record-breaking wet winter and spring, and the action is not over yet.   The good news:  we should transition to an El Nino next winter, which should be associated with a different, and drier, atmospheric circulation.


_______________________

How will Northwest Weather Change Under Global Warming?  Help Us Determine the Local Impacts of Climate Change

Society needs to know the regional impacts of climate change and several of us at the UW are trying to provide this information with state-of-the-art high resolution climate modeling.  With Federal funding unavailable, we are experimenting with a community funding to build this effort.  If you want more information or are interested in helping, please go here.  The full link is: https://uw.useed.net/projects/822/home    All contributions to the UW are tax deductible.

Friday, April 21, 2017

Why the March for Science is a Bad Idea

On Saturday, thousands of people around the country will take part in a March for Science.  There will be a lot of well-meaning folks participating, most of them concerned about the activities and intent of the current administration.

But for reasons I will outline below, I believe they will be harming science more than helping.  They will feel better for sure, but they will do little to advance the cause they care about, and possibly do long-term harm.
There are many reasons why the Science March such a bad idea.

(1)  The Science March is overly political and endangers the relationship between science and society.

Science play a critical role in civic life, acting as non-political source of information about the the natural environment and as the generator of useful technologies.  Scientists are credible only when their information is considered unbiased and not politically motivated.   The lack of political bias is why both sides of the aisle have supported the nation's large scientific establishment over many years.

The Science March is clearly political and is an attempt to put pressure on the Trump administration.  It will be seen as political by everyone and particularly those it means to pressure.    Furthermore, the major concern driving this march is not science in general, but of the Trump administration's appointments and future actions regarding climate science and fossil fuel regulations.

(2)  The Science March Makes Science a Target

The march will identify supporters of science as being against the Trump administration, putting a big target on the back of the U.S. science establishment.
I have just finished reading my third book on Donald Trump.   One thing is clear: he tends to act very aggressively against those who cross him, and particularly those that attack his public image.  Do science supporters really want to provoke him unnecessarily and to little advantage?

Furthermore, there is no reason to think that Donald Trump is anti-science in general or that he really has any strong feelings about science.   His anti-climate rhetoric might be similar to his pro-Russian talk: something that might rapidly alter as circumstances change. Do science supporters really want to push him into a corner?

(3)  Republicans are Not Anti-Science and Can Protect Most Science If They Are Given a Chance.

Science research has generally done well when Republicans have been in control.  For example, climate research funding went up substantially during the last Bush administration.  Recently, the Weather Research and Forecasting Innovation Act passed the Republican-controlled Senate and House with overwhelming support.  I have talked to a number of Republican staffers on critical House committees who told me that since they control the "purse" they could protect most of the science establishment.
Climate research is only a small part of the Federal scientific portfolio.  Having questions about climate issues does not make one generally anti-science.

(4)   The March will Fuel Partisanship and Polarization in the Nation

A key problem in the nation has been the polarization of the population and Congress.  The moderate center of the country has been severely weakened, and a cultural divide has developed between the liberal coasts and the conservative interior.  Between haves and have nots.  Will a large protest march for science help bridge this divide?   Or will it identify scientists with other, generally left-leaning, protest groups?  Will those hurting economically that voted for Trump be more likely to support science after a protest? I suspect not.

This is not going to win over Trump supporters

(5)   We Really Don't Know What the Current Congress Will Do Regarding Science Budgets

Congress has not passed a budget yet, so there is little information about what cut-backs or rebudgeting will occur.  Why protest without knowing whether there will be significant reductions and in what areas?

(6)  The March Does Not Have Clear, Explicit Goals.

Go to the the March on Science website. Try to figure out what they are marching to change.  According to their website the March is a "first step of a global movement to defend the vital role science plays in our health, safety, economies, and governments."   Who is trying to reduce this "vital role?"   What actions exactly are being called for?

(7)  The March Organizers Will Not Control the Message

Overtly political or damaging messaging could easily be presented during the march.  What is to going to stop anti administration signage?   What happens if violent or disruptive protestors join the marches?



(8)  There Weren't Marches When Democratic Administrations Distorted Science and Particularly Climate Science

The political nature of this march is highlighted by the fact that there was no call for protecting science  or marches when Democratic administrations played fast and loose with science.   A good example was the sensational and unsupportable claims of the Obama administration science adviser (John Holdren) that eastern U.S. cold waves were caused by global warming.   Demonstrably wrong, but few protested this obvious distortion and politicization of science.  Or the claims by NY Govenor Cuomo that Hurricane Sandy was the result of climate change.  Both political parties have distorted or miscommunicated science when it was in their political interests.



A Better Approach

Instead of marching and being seen as opponents of the current administration, scientists and their supporters would be far more effective if they greatly increased their outreach to the community, communicating both the process and results of science.


Scientists should go into the community and talk about their science.  Speak at local libraries, in schools, and fraternal organizations.   Folks are extraordinarily interested in what we (scientists) have to say.  Make an effort to connect with political leaders.  Use social media (like blogs!). Nothing is more powerful than person to person contact.   Help increase science literacy.  In the long term, public understanding of science and the motivations of scientists is the most powerful tool for protecting the  health of the nation's science enterprise.

Worried that some folks feel climate change is a hoax?  A good reason to have climate scientists enhance active outreach into communities doubting the science.

I won't be out marching on Saturday, but I will continue my science outreach using this blog, my radio show on KNKX, and talks at local groups.   And yes, by continuing do my science, including the determination of the regional impacts of global warming.

Let me end, by saying that there is nothing wrong with marches against the current administration or the current Republican leadership in Congress. But don't involve science in it.  If folks are honest, they would admit that this is basically a political protest against the current leadership in DC. Perhaps the most problematic leadership in the history of our country.   So have a march, but don't use science as a cover, and don't put science at risk.  

Marches like this don't build bridges.   And in a highly polarized society, bridges are desperately needed.   Several of us have built bridges in the area of weather prediction, and this week the Weather Forecast and Research Innovation Bill was signed into law.  Let's build bridges in the area of climate change.  It can be done if we have the wisdom and patience to do so.


Wednesday, April 19, 2017

Major Weather Bill Signed by the President Today

A major piece of legislation designed to improve U.S. weather and seasonal prediction was signed today by President Trump.

The bill, the Weather Research and Forecasting Innovation Act of 2017, will support a wide range of improvements in U.S. weather prediction, enhance tsunami warning capabilities, and even take on the important task of dealing with weather radar gaps around the nation.



A refreshing aspect about the bill was its overwhelming bipartisan support, including passage by unanimous consent in the Senate.  Sponsors of the bill were from both sides of the aisle.  

What does this bill do?   

First, is calls on NOAA's Office of Oceanic and Atmospheric Research to conduct a program to improve forecasting of weather events and their effects, with a special focus on high impact weather events.


The National Weather Service must collect and utilize information to make reliable and timely forecasts of subseasonal and seasonal temperature and precipitation.  (Subseasonal forecasting is forecasting weather between two weeks and three months and seasonal forecasting is between three months and two years.)

The bill provides for technology transfers between the National Weather Service and private sector weather companies and universities to improve forecasting.

NOAA must complete and operationalize the Constellation Observing System for Meteorology, Ionosphere, and Climate (a weather satellite program which uses global navigation systems to provide vertical soundings all over the world.)

It encourages NOAA to contract with the private sector to obtain data for weather forecasting.

And much more.

Our own Senator Cantwell played a major, positive role in this legislation. She added a section "To authorize and strengthen the tsunami detection, forecast, warning, research, and mitigation program of the National Oceanic and Atmospheric Administration".  And she worked with Republican legislators to require an evaluation of the gaps in U.S. weather radar coverage.

Senator Maria Cantwell

The bill authorizes the spending of $170M on the improvements, but those funds still need to be appropriated.

Why ia this bill important?   Because US weather prediction is a shadow of what it could be.  Because we have too many modeling systems and a lack of coordination of effort.  The bill represents an effort by Congress to step in and tell government agencies they can (and should) do better.

Strange silence in the media

You would think that a presidential signing of such a positive bipartisan bill would get a lot of press coverage.   But as of 9 PM Wednesday, I could not find a single story on the bill in any major media outlet.  Why?  

One possibility is that for some reason the mainstream media has not noticed this signing.  

Another is that some folks are nervous that the funds for improving weather to seasonal prediction might result in less support for climate research.  My take is that if some in Congress are determined to reduce climate research, it is far better to use the money for weather/seasonal prediction than lose the money entirely.  Climate and weather/seasonal models are basically the same and improving short-term predictions can only help climate projections.  


There may be some reluctance among some to give President Trump and Republican legislators credit for their efforts on this bill, but I believe they deserve credit for making a very positive contribution to enhancing the nation's ability to predict the weather, skillfully project seasonal changes, and to warn about imminent tsunamis.  

The nation needs to come together to deal with our failing infrastructure and needs of our citizens.   This bill is an example of the kind of positive things we can accomplish if we work together.  

_______________________

How will Northwest Weather Change Under Global Warming?  Help Us Determine the Local Impacts of Climate Change

Society needs to know the regional impacts of climate change and several of us at the UW are trying to provide this information with state-of-the-art high resolution climate modeling.  With Federal funding unavailable, we are experimenting with a community funding to build this effort.  If you want more information or are interested in helping, please go here.  The full link is: https://uw.useed.net/projects/822/home    All contributions to the UW are tax deductible.




Monday, April 17, 2017

Why aren't my seeds growing?

A few weeks ago, I planted some grass seeds where my lawn had turned to dirt.
Nothing happened.

And then a possible reason occurred to me:  the ground was too cold to germinate the seeds.   After a cool winter and a cloudy/wet spring, the soil temperatures HAD to be cooler than normal.

What my lawn looks like

Let's check.

I looked around at a number of seed company and horticultural websites, and their recommended soil temperatures for cool-season grass seed were generally similar.  Here is an example of their advice:

Cool season grass, such as Fescue, germinate best when the soil temperatures are between 50° and 65° degrees F.  These soil temperatures usually occur when the daytime air temperatures are between 60° and 75° degrees.

And what about other types of seeds?  Most advice follows the charts below, with optimal temperatures indicated by the black dots and "practical" by the green ones.  In western Washington, you can forget the optimal temperatures, but the practical ones are within reach for some vegetables.   Beets to spinach are no problem even here during early spring....but what about beans, squash and other favorites that require 60sF to play the germination game?


One network that has a lot of soil temperature measurements is the WSU AgweatherNet.  Their sensors are placed at a relatively deep 8 inches and I would expect that to be several degrees cooler than observed near the surface on sunny days, but useful numbers on cloudy ones.  Furthermore, since the ground is moist, evaporation will cool near-surface temperatures.  

Here the AgWeatherNet soil temperatures for today.  Low to mid-fifties are the rule in western Washington, with a few even in the upper forties.  During the weekend, I stuck a thermometer into the soil where my germination was poor:  54F.  No wonder.


Soil temperatures in my area of north Seattle are thus marginal for grass seed, which means a low percentage of germination.  I need to wait a month for better luck.

I also wanted to plant some veggie seeds (e.g., beans, zucchini), but really need to wait for most of them if I want to directly sow into the soil.   If the above guidance is crrrect, I should wait until soil temperatures are into the 60s F.  When does that typically happen?

To find out, here is plot of soil temperatures for the last few years in north Seattle.  This year is clearly the coolest of the bunch.  Typically, soil temperatures get to 60F around May 1.    This year, mid-May is a better bet.


Now the next 72h looks quite wet (see WRF model forecast below)...very wet for late April...so soil temperatures aren't going anywhere quickly.  Even California gets substantial precipitation, which IS very unusual for this time of year.


So keep your seeds in storage for a while--I might plant my veggie seeds indoors and transplant the small plants... a good approach in our short-season climate;

_______________________

How will Northwest Weather Change Under Global Warming?  Help Us Determine the Local Impacts of Climate Change

Society needs to know the regional impacts of climate change and several of us at the UW are trying to provide this information with state-of-the-art high resolution climate modeling.  With Federal funding unavailable, we are experimenting with a community funding to build this effort.  If you want more information or are interested in helping, please go here.  The full link is: https://uw.useed.net/projects/822/home    All contributions to the UW are tax deductible.

Saturday, April 15, 2017

The Beauty and Danger of Evaporating Precipitation

With our wet spring and winter, folks may think that all the precipitation falling out of our clouds is reaching the surface, but this is not true;  substantial amounts evaporate before hitting the surface and such evaporation of falling precipitation can be a beautiful sight to behold.

It also has a name:  virga.  And is seen as thin tendrils of precipitation falling out of cloud bases, frequently with curved and angled trajectories.  Virga can be made up of either ice crystals or rain drops.  Sometimes it reaches the surface (all too often around here!) and sometimes the precipitation evaporates before reaching the surface.

This week Greg Johnson of Skunk Bay Weather shared some wonderful images and videos that I would like to show you--like the image shown below.


The amount of evaporation (liquid to vapor) or sublimation (ice crystal to vapor) of the falling precipitation varies, depending the relative humidity of the air below, the precipitation rate, the height of cloud base, and precipitation type.    Low relatively humidity obviously results in greater evaporation or sublimation.

One thing that is so beautiful about virga is the often curved nature of the falling precipitation, which is also called fall streaks.  Why?  Because winds often change with height (generally faster aloft) and thus the falling precipitation, which moves with the winds, is pushed along by varying amounts as it falls.


Virga has a distinctive beauty and this video proved by Greg Johnson is wonderful to watch.

Marching Virga.... April 12, 2017 from SkunkBayWeather on Vimeo.


The precipitation from virga cools by evaporation (and sublimation) as it falls, particularly if there is dry air below cloud base.  Cool air is denser than warmer air and so it sinks, accelerating down to the surface.    

Undoubtedly you have experienced that effect.  On a threatening day, did you ever feel the temperature chill and the winds pick up right before the rain starts?   That is the cool, downdraft air from virga, whose precipitation evaporated before it reached the surface.  Eventually, the air becomes saturated and the precipitation reaches the ground.

Evaporating precipitation associated with virga can also be deadly.    Intense evaporation and cooling results in a very strong downdraft that spreads out when it hits the surface (see figure). Called a downburst (or microburst), these phenomena can produce winds of 50-100+ mph and has brought down commercial jets.


Like so many things in life, virga can be beautiful, but it has another, more dangerous, side.

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For those that are interested, I will be giving a talk at Bellevue College next Tuesday (April 18th) on the politicization of climate science at 12:30 PM.  This is open to the public. And they have pizza.


_______________________


How will Northwest Weather Change Under Global Warming?  Help Us Determine the Local Impacts of Climate Change

Society needs to know the regional impacts of climate change and several of us at the UW are trying to provide this information with state-of-the-art high resolution climate modeling.  With Federal funding unavailable, we are experimenting with a community funding to build this effort.  If you want more information or are interested in helping, please go here.  The full link is: https://uw.useed.net/projects/822/home    All contributions to the UW are tax deductible.


Thursday, April 13, 2017

Record Breaking Precipitation in California: Is Global Warming to Blame?

This has been an extraordinarily wet year over the entire west coast of the U.S., with many locations approaching or exceeding all time record precipitation amounts for the water year (which starts October 1).  

The question is why?

A number of media outlets and environmental advocacy groups are claiming (or strongly suggesting) that the heavy rainfall this year and the preceding dry period over California are the result of human-caused global warming.



 Is human-induced global warming associated with increasing greenhouse gases really the cause?

I believe that the evidence and good sciences indicates that the answer is no--the nature of what happened this year does not reflect what we expect from global warming.  Let me provide you with the evidence.

The precipitation that has hit California this winter has been truly extraordinary. I mean crazy high.

Want proof? The State of California has an index of Northern Sierra Precipitation for the total amount starting October 1. Yesterday, we beat the all time record for entire water year, and there is 5.5 months left in the water year.  This is a startling record to break.


Here is the percentage of normal precipitation for the western U.S. for the water year so far.  Your eyes are not lying to you....much of norther Sierra and neighboring areas had over 200% of normal precipitation.

How much above normal does this mean in inches?  As shown in the figure below for the same period, we are talking over TWENTY inches more than normal from central CA to the Pacific Northwest.   Amazing.


So much precipitation that most of the reservoirs in California went from well below normal to full.  No one expected that.

Now some in the media and some "advocacy" groups have been suggesting or stating that the heavy this year is the result of or "consistent with" the effects of global warming.   But they are not providing a scientifically based conclusion.
(As an aside, this is an area in which I have done research and have published several papers in the peer-reviewed literature.)

There is a substantial literature on the impacts of global warming on West Coast precipitation.  A number make use of the output of global climate models forced by increasing greenhouse gases.

An excellent paper by Neelin et al., 2013 in the Journal of Climate presented the average change in precipitation for December through February from a 15-member ensemble of the latest (CMIP-5) climate models (see  below). This map shows the difference between the precipitation between the end of the 20th and 21st centuries if greenhouse gases increase rapidly (RCP 8.5).   Note that there is small increase over southern California and a modest increase (about .5-1 mm per day or around 1.75 to 3.5 inches) for the entire winter.  And keep in mind, this is the magnitude of the change by the end of the century, today, the impacts of global warming would be much, much less (perhaps a tenth of this).


Clearly, the precipitation enhancement this winter is hugely greater than expected from global warming.  These results also speak to the precipitation droughts of the past few years--this is NOT what climate models are suggesting will occur from global warming.  California will not be getting less precipitation as the planet warms (although Mexico will get drier)


Climate models do suggest that the largest atmospheric rivers will get much more intense--my work with Dr. Mike Warner in published work in the Journal of Geophysical Research suggests that the strongest atmospheric rivers will be enhanced by 30-40%.   But that is not what what observed this winter; although we had a few strong atmospheric rivers, none were exceptional, something that is supported by the lack of major flooding events along the West Coast.

Instead of mega atmospheric rivers, West Coast precipitation was characterized by a seemingly unending number of modest events.  This is made evident by the precipitation record at San Francisco below (dark green is actual precipitation and light green is normal).


Seattle-Tacoma Airport experienced the same thing.  Here is the plot of daily rainfall (red color) and the daily records (green lines).  Rain nearly every day, but very few events reached daily records.  Not what you would expect from a global warming signal.

Furthermore, the origin of the persistent precipitation is no mystery--it was due to a very persistent and anomalous upper atmospheric circulation pattern.

To illustrate, here is upper atmospheric (500 hPa, around 18,000 ft) anomaly (difference from normal) of 500 hPa heights (you can think of it like pressure) for the last 90 days.  Huge anomaly, with unusually low pressure over the Northwest and offshore waters, a big ridge (high pressure) over the eastern U.S. and the southern NE Pacific, and other large anomalies offshore.

A low off our coast and a ridge to our south brings moist southwesterly flow and lots of precipitation over the West Coast.  This pattern may well have been forced by unusual convection (thunderstorms) over the Indonesian and environs.
There is no reason to expect this kind of pattern is caused by global warming, since the climate models do not produce this configuration when they are forced by increasing greenhouse gases.

Not convinced yet?   If global warming caused by steadily increasing greenhouse gases was the cause of the recent drought or this year's mega precipitation, you would expect to see a trend in California precipitation.  As you can see below (a plot of Oct-March precipitation over CA from the Western Region Climate Center), there is very little trend (I would not look before 1940 since there was far fewer stations then).   California has a lot of natural variability of precipitation with a few dry years followed by a very wet year or two.  But there is no real trend.  Global warming would produce a trend.


In summary, examining the California precipitation variability from a number of directions leads to the same, consistent conclusion:  there is no scientific evidence or reason to believe that recent variations in precipitation have anything to do with global warming.
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For those that are interested, I will be giving a talk at Bellevue College next Tuesday (April 18th) on the politicization of climate science at 12:30 PM.  This is open to the public. And they have pizza.


_______________________


How will Northwest Weather Change Under Global Warming?  Help Us Determine the Local Impacts of Climate Change

Society needs to know the regional impacts of climate change and several of us at the UW are trying to provide this information with state-of-the-art high resolution climate modeling.  With Federal funding unavailable, we are experimenting with a community funding to build this effort.  If you want more information or are interested in helping, please go here.  The full link is: https://uw.useed.net/projects/822/home    All contributions to the UW are tax deductible.