Friday, May 22, 2015

Lightning Fest Starts the Memorial Day Weekend

Nature is supplying its own fireworks to signal the Memorial Day weekend.   For the past several days, large numbers of thunderstorms have moved westward across eastern Oregon and Washington, while others have developed over the Cascades and Olympics.

To illustrate, here is summary of the lightning strikes for Thursday.  Eastern Oregon, Idaho, and the Washington Cascades were covered by lightning.

A particularly strong thunderstorm cell hit Yakima Thursday evening, which received about an inch of rain within an hour.  The radar at 7:50 PM Thursday shows the heavy rain (red colors)

 
And localized flooding was observed around the area.

A lot more action occurred today (Friday), with a squall line of thunderstorms moving across eastern Washington, with heavy rain and gusty winds.   The radar at 7 PM this evening shows the action (red is the heaviest rain or hail):

And, of course, this heavy rain was associated with lots of lightning.   We are fortunate that all this is happening early in the summer, with the ground moist enough so that the lightning is not initiating fires.  The story will be different in two months.

The configuration of unusually persistent easterly flow and lots of thunderstorm east of the Cascade crest, which has held in place over the past week or two, may be the result of the strong El Nino that is developing.   My colleague, Nick Bond, who is also State Climatologist, examined the relationship between El Nino and regional precipitation (see the figure below, which shows the correlation between El Nino and precipitation for the month of May).  Eastern WA and Oregon are wetter than normal, while western WA is drier than normal--EXACTLY what has happened.


The million dollar question all of you are asking is what this weekend will be like.  Will the Folklife Festival be a rain out?  Will you get wet hiking in the Cascades?

Actually, it doesn't look that bad.  Here is the total precipitation for the next 72 hr starting 5 AM Saturday.  Relatively dry for most of western Oregon and Washington, with the major exception being light showers in the Cascades.  Much wetter over the Rockies and Nevada.


We do have marine air pushing in west of the Cascades, so no heat waves are ahead.  Highs in the mid-60s and considerable clouds over the lowlands.


Wednesday, May 20, 2015

Drought Misinformation

There have been a number of stories in the press and on the web about water issues this summer in the Northwest; some are reasonable but a disturbing number are exaggerating and distorting the situation, predicting a catastrophic wildfire season and billions of dollars in crop loses.  And some folks in the political arena are playing a bit lose with the facts as well.

You want some examples?  Crosscut calls out a SUPERDROUGHT.


This over-the-top piece does not stop with this year:

"The 2015 superdrought will likely be a harrowing experience for many state citizens, and could be followed by another, similarly terrible year.'

 Others talk about a TINDERBOMB due to low snowpack


Or in the Oregonian:

Will there be a superdrought this summer over the Pacific Northwest?   Will low snowpack bring huge wildfires?  Let's get beyond the hype and look at data and forecasts.

First, let's be clear.  There is no drought over the Pacific Northwest and by that I mean no precipitation drought.  For the last six months, here is the % of normal precipitation over the western U.S.  Most of Washington State and the eastern half of Oregon received 90-110% of normal.  The rest was at least 70%.   California and Nevada is a different story, with real drought.   You can see why William Shatner wants our water.

What about conditions on the ground?  One of the most considered measures of drought is the Palmer Drought Severity Index.   Here are the latest values.  Most of Washington State is near normal and eastern Oregon is wetter than normal!

What about the the NOAA crop moisture index?  Normal.
And the last two weeks have been unusually wet  (green and blue) over the eastern side of the Cascades.

And this evening's WRF precipitation forecast for the next 72h looks like something that would inspire Noah to start building his ark:

While the latest forecast of total rain over the next 9 days from the National Weather Service's GFS model would bring happiness to any Northwest duck.

And keep in mind that Columbia River flows, draining off the higher terrain of British Columbia, which had a better snowpack AND more precipitation, will only be slightly below normal.   Plenty of water for hydropower, irrigation from the Columbia, and fish in the river.  And because of substantial reservoirs and wise stewardship, nearly all of the populated areas of the region will have sufficient water.

So this talk about the Northwest being in a drought, super or not, is really problematic.    We have had near normal precipitation, our soil moisture is near normal, our reservoirs are full, the Columbia is near normal, and the drier parts of the state are being hit by wetter than normal conditions during late spring.    

We DO have a lack of snowpack because of the warm temperatures last winter that resulted in rain but little snow in the mountains.    So maybe it is ok to talk of a snow drought, but that is a bit confusing to some perhaps.  This snow drought will be problematic for fish on some rivers (e.g., draining the Olympics), but there is little we can do for them.  Nature is cruel sometime.

So how worried should we be about wild fires due to the low snowpack?   And what about other factors?

I have talked to my colleagues in the wildfire business and most of them feel the snowpack issue is overblown.   They tell me that the key determiner of whether there will be extensive fires in the summer are:
  1. Whether we are much warmer than normal in July and August
  2. Whether there are a lot of thunderstorms to initiate fires.
  3. Whether we are much drier than normal in July and August


Regarding the last bullet, we are normally dry during our summer, but rain can moisten the "fuels" and lessen the fire risk.

There is good reason to suspect snowpack has only a small impact on wildfire frequency and intensity.  First, the differences in snowpack between good and bad years is pretty minimal by the time of the main fire season, which is roughly from mid-summer to early fall.   Second, differences in snowpack early in the season between good and bad years is mainly at higher elevations, while most of the significant fires, and certainly the ones the affect most people, are at low elevations.   To show this, here are the areas of the major fires of the past 15 years.  Most are on the lower slopes of terrain east of the Cascade crest or in relatively low (and snowfree) coastal mountains.


There are a few papers correlating lack of snowpack with increased wildfire threat (e.g., Westerling et al. 2006), but I believe they have a fatal flaw.   Their low snowpack years were also precipitation drought years, which is NOT TRUE of this year.

So if snowpack won't be a major issue, what about temperature, precipitation, and thunderstorms?

Our best guidance for the seasonal predictions is the NOAA Climate Forecast System (CFS) model.   For temperature, its forecasts have been clear and robust.   Warmer than normal (see below) over our region.   That would enhance wildfire risk.
 Precipitation is a different story.  Nearly normal over Washington, but a bit wetter over eastern Oregon.
Predicted soil moisture?  Generally, near normal except for eastern Oregon, where it would be wetter than normal.
But then there is the thunderstorm issue...and folks, THAT is the wildcard.  The enhanced precipitation over the Rockies suggests more thunderstorms over that region and perhaps into eastern Oregon.  Might those thunderstorms get to up and start fires?   On the other hand, the CFS model predicts enhanced ridging over our region, which would lessen thunderstorms.

The bottom line in all this, is that a more nuanced view of the current "snow drought" situation is called for and the prediction of more wildfires is no slam dunk.  Talk of superdroughts is really nonsense.  

There is certainly no reason to expect fewer than normal wildfires and the warm temperatures will modest increase wildfires potential.  But the lack of snowpack is a minor issue.   Much is riding on the frequency of thunderstorms, and there is considerable uncertainty how that will play out.

As I have said many times, this year has many of the characteristics of 2070, when global warming will be significant.  That is why the work of Governor Inslee and the Department of Ecology to take all possible steps to adapt to a low-snowpack year is appropriate and welcome.  We need to figure out how to deal with a lack of snowpack, while preserving our agriculture, drinking water, and as much as possible of natural fauna/flora (e.g., salmon).  But hyping and exaggerating the situation is not helpful.

And for those in western Washington...be prepared for thunderstorms later tomorrow and into the early morning hours of Friday.


Monday, May 18, 2015

Why last winter was so unusual

Last winter and this spring have been a different animals meteorologically, at odds with anything we have seen before.

So unique that it should give forecasters pause.

So unique that it  is probably not the result of global warming.


Let's start with the Big Kahuna.  The lack of snow.   For a number of locations, this year had the lowest April 1 snowpack on record.  Here is a plot of April 1 snowpack (snow water) over the Northwest from 1984 to 2015 (green lines).  2015 was the lowest.


But it is more interesting than that!  The lack of snowpack was NOT associated with a lack of precipitation....which is really unprecedented.   Virtually every other low snowpack year was a precipitation drought year as well.  But NOT this year.   To demonstrate, here is a plot of average winter precipitation since 1950 over Washington State.  Our last winter was run of the mill.  But check out the previous low snowpack years (2005, 2001, 1992):  all low precipitation years.


So how could we have normal precipitation but poor snowpack?   The answer:  crazy warm temperatures.  Take a look at a plot of Washington State Nov-Feb. temperatures since 1950.  This year was the warmest.


But wait, there's more!   Something weird and extremely unusual is occurring in the tropical Pacific.  El Nino is revving up rapidly, which is very uncommon during the spring.  The sea surface temperature in the central Pacific (Nino 3.4 area) shows the warming.


It is increasingly looking like we may have a super El Nino later this year.  And that will have a significant impact on NW weather.

So why are these unusual events happening?

Some will be quick to blame global warming from increasing greenhouse gases, but that is an unlikely explanation of a sudden, one-off year like this.  Greenhouse gas induced changes would be expected to develop more gradually.

Random, natural variability is more likely as the cause.

Of course, some will have other explanations: aliens, secret government weather control projects gone wrong and other  ideas we won't get into.

There is simply no analog for last winter and this spring in the Northwest.  It stands by itself.  And that is why folks (and the media) have to be very, very careful in assuming what the impacts of this weird weather will be.

My next blog will consider one such claim:  that the low snowpack will result in huge and frequent wildfires this summer.   It may sound plausible, but as we will see, there are problems with some of the assumption being made.

Saturday, May 16, 2015

Weather Role Reversal

It is always fun when the normal weather patterns reverse.

This week for instance, the normal precipitation pattern reversed over Washington State, with eastern Washington getting hit hard, while only light showers damped the west.  Here is the percentage of normal precipitation over the past week.  Pretty dramatic!  Some locations around Yakima and Tri-Cities had over 800% of normal rain.  We are talking about 25% of their ANNUAL precipitation in one day!  The Olympics, the home of the rain forests?  Bone dry.


This role reversal was associated with a reversal of the wind direction and storm locations, with a low center moving northward east of the Cascades and easterly flow causing upslope over the eastern slopes of the Cascades.

But role reversals have been occurring over a larger scale as well.  For much of the winter and early spring, the eastern U.S. has been anomalously cold, while the western U.S. has been unusually warm (the reason for the famous snow drought that has caused Governor Inslee to make a statewide drought declaration).  But what about last week?

The roles have reversed.  As shown by the graphic below (max temps, for the last week), it has been warmer than normal over the northeast and colder than normal in the West.


Why?  Because the large scale atmospheric circulation pattern has changed dramatically.  For much of the last year there has been enhanced ridging (high pressure) in the west and troughing (low pressure) in the east.  Like this.



But last week the pattern reversed, with a broad trough over the western U.S.  Big difference!


This change of circulations has also produced a role reversal along the West Coast.  For most of the winter and early spring, the Northwest has been relatively wet while California has been dry.  Oregon has been much drier than Washington.   But with the deep West Coast trough, the jet stream has been heading into California and they have been much wetter than normal.  Heavy rain hit San Diego and the folks freaked out there (see graphic)


And this atmospheric pattern will reverse the situation between us and Oregon, which is going to get hit VERY hard with moderate to heavy precipitation during the next week.  Here is the forecast precipitation for the next 72h.  Lost of rain from eastern Oregon into the Willamette, as well as northern California.  Oregon ducks will be happy.


The next 72h?   Lots of rain over eastern Oregon, but spreading into SW Washington.  California gets plenty.  We are talking about substantial drought relief for many, considering such sustained heavy precipitation is unusual for this time of the year in the West.

Why is this happening?  Some wags might smirk that it results from all the drought declarations, which are like red flags in front of the meteorological weather gods.  But there is another possibility: an extraordinarily resurgent El Nino that is revving up in the tropical Pacific in a way that is highly unusual for this time of the year.
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Sunday Morning Update:  The eastern slopes of the north Cascades have been hit by substantial rain, with some locations getting over an inch of rain during the last day.  Here aer the 24h numbers ending 9 AM Sunday.  There are just the areas that often experience wildfires.


_____________________________________
Announcement:  On June 3, I will be on the Seattle Channel's Civic Cocktail with Governor Inslee.  If you would like to be in the audience, you can get tickets at: http://www.seattlechannel.org/CivicCocktail.  They charge, but you get appetizers with their no-host bar.

Friday, May 15, 2015

Seattle's Erratic Support of Bicycle Commuting

Today is Bicycle Friday, the day that Seattle's bicycle commuters celebrate and goodies of all kinds are found near local commuting routes.

But all this celebration does not cover up an important truth:  Seattle does not have a consistent and effective policy for making bicycle commuting an enjoyable and safe mode of transportation in the city.


The evidence of Seattle's halting, inconsistent, and sometimes wasteful policies are easy to demonstrate.   There are also been a few success stories that show what the city can do when it tries.

Fact Number 1:  Seattle is incapable of keeping its main bicycle superhighway, the Burke Gilman Trail, in decent condition.

Thousands of bicycle commuters use the trail every day. I blogged in depth about the sad state of the trail earlier, with heaving roots, cracks, holes, and broken edges.  After my and other complaints, Councilwoman Jean Godden (the only councilperson who seemed to care about the problem) and representatives of the Park's Dept. met with me on the trail.  They promised action.     Some work was done, but many of the worst sections have not been fixed (see pictures) and dangerous, slapdash plywood "repairs" on the 35th Ave bridge have not been taken care of.   When they do some repairs they are cursory and not permanent.  Repair work has now stopped completely.  What will it take to get the Parks Department to take Burke-Gilman trail maintenance seriously?





Fact Number 2:  There are no protected bicycle routes into the city from the North End.  Or the south end.

Many folks living north of the Ship Canal would like to commute into the city by bicycle. Amazingly, the city has not established a single route whereby a cyclist can commute without serious and dangerous contention with cars.  I have tried it several times....I am still shaking from the experiences.  If Seattle is serious about fostering bicycle commuting there MUST be protected bike routes.  It is as simple as that.

Fact Number 3:  The city has wasted large amount of money on feel-good, PR-rich schemes that have not helped the situation.

The first was the lame scheme to paint bicycle symbols (sharrows) on busy streets.  Somehow that supposed made the streets safe for cyclists.  Tens, if not hundreds of thousands, of dollars were wasted on this dangerous and ill-conceived scheme.  And many cyclists are hit by cars and opening car doors on sharrow-painted streets.

Really safe!  LOL

Perhaps the biggest waste of money on feel-good schemes is the Pronto bicycle rental stations placed around the city.   Millions of dollars were spent to acquire the bikes and the docking stations.  And Pronto reports the cost of the enterprise is about $110,000 a month.   I have seen only ONE Pronto bicycle being ridden around the UW or on the Burke Gilman trail.  The usage statistics show dismal popularity.  For example, in 2014, each bicycle was used for 1/2 a trip per day.  You read that right. ONE HALF a trip per day.  Want to use a Pronto bicycle for a day.  That will be $77.00!    Their whole pricing structure pushes short rides and discourages extended use by tourists or folks wanting a longer ride.  At some docking areas (e.g., Children's Hospital), there is almost no usage.   The Seattle media has not touched this disaster yet... perhaps Danny Westneat of the Times will take it on after he deals with the pesticide-spraying shellfish industry.


Lonely, but expensive bikes with no where to go

When will the political class take bicycle commuting seriously?

Imagine if the city created FOUR absolutely protected bike routes into and out of the city (form NW, NE, SW, and SE Seattle).

Imagine if the Burke-Gilman and other bike paths were properly maintained?

Perhaps it is time for city officials and councilmembers to stop taking PR opportunities for things they can't change (like kayaking around Shell Oil drilling platforms) and do something that will really help reduce carbon usage and greatly enhance the livability of the city (like dealing with the bicycle commuting problem).  There is so much talk in the city for living green and having a low-carbon footprint.  Yet, the city seems powerless to plan and execute a bold plan for making safe, effective bike commuting a reality.   Really sad.

There are some reasons for hope.  Some safe bicycling areas have been created downtown, like the second ave protected bike lane (see pic)


And near U. Village, some of the crossings of the Burke-Gilman Trail have been made much safer:


And some innovative new companies, like Rider Oasis, want to revolutionize bike maintenance and make bicycle-oriented products available 24-h a day.


We have waited long enough to see Seattle becoming a truly bicycle-friendly city.  The increasing traffic and density of the city calls for making bicycle commuting a viable alternative.  Does anyone have the vision and leadership to make this happen?  Kayaking around Shell Oil platforms and riding around Pronto bicycles might get a lot of press, but someone has to do the real work that will make a real difference.

_____________________________________
Announcement:  On June 3, I will be on the Seattle Channel's Civic Cocktail with Governor Inslee.  If you would like to be in the audience, you can get tickets at : http://www.seattlechannel.org/CivicCocktail.  They charge, but you get appetizers with their no-host bar.

Wednesday, May 13, 2015

Eastern Washington Gets Some Drought Relief

Next time you go to a local casino, you might want to take some farmers from the Roza Irrigation District in eastern Washington for good luck.  Those are the folks, with farms from roughly Yakima to the Tri-Cities (see map), that decided on May 11th to stop irrigating for several weeks in order to save water for later in the season.

Their gamble paid off, big time.   Today, substantial rain, associated with easterly flow circulating around a low pressure area east of the mountains, drenched the inland empire, with many locations enjoying 1-2 inches of steady rain this morning and early afternoon.  In contrast, the usually wetter western sides of the Cascades were far drier.   How could that be?

This rain was sufficient to thoroughly soak the ground and obviate the need for irrigation for a while, and even provided some water for the Yakima River reservoirs. The weather gods were clearly smiling on the eastern Washington agricultural community.

Let me show you some of the data.  Here is the 24h precipitation ending 5 PM from the National Weather Service observation site for eastern Washington (the reds and orange colors are the higher amounts, click on map to enlarge). Nearly two inches of rain fell northwest of the Blue Mountains around Walla Walla and similar amounts occurred over the Horse Heaven Hills above the Tri-Cities.   Much of the Roza district had over an inch, and substantial amounts fell over the eastern slopes of the Cascades.


The daily precipitation from the WSU Ag Weather network shows a similar situation (see map) with over two inches south of Benton City.   A dry wheat farmer from there called me today....he was a very happy fella.

The rain was heavy enough that some roadways were flooded, as were some commercial districts (see article below).

This situation was relatively well forecast by the models several days ago (my past blog is proof!).

So why so much rain on the eastern side compared to the west of the Cascades?

The winds in the lower atmosphere over eastern Washington were from the east or northeast, not the normal westerly direction.  The cause? A small, but intense, low pressure system moved northward east of the Cascades today, as illustrated by a weather map for around 5000 ft valid at 5 AM this morning (see graphic).  This system had a band of moisture that circled the low center, a band that was directed over southeastern WA and NW Oregon.


An infrared satellite image at the same time and a radar depiction at 9 AM, illustrate this "wrap around" plume of moisture.


More good news for eastern Washington farmers: cooler than normal, occasionally showery, weather is ahead, although not like the torrents of today. And the aggressive storage of water for the Yakima project by the Bureau of Reclamation is still obvious (see plot).  Even pulling water for agriculture and fish during the last few weeks, the total reservoir levels (blue lines) are still above average for this time of the year.  Hopefully, the recent rains and conservation in the Roza district will cause the decline in reservoir level to slow during the next week.

I am a bit more optimistic than some regarding eastern WA agriculture this summer.   Our region is undergoing a snowpack drought, not a precipitation drought.  Reservoir managers have stored more water than usual.  And, how do I say this diplomatically?   Some farmers have wasted water, including spraying during mid-days when evaporation is huge.  As noted in a recent radio segment by NPR's Ana King, some farmers/orchard owners are switching to drip irrigation, saving as much as 50% of the water.  Improving irrigation technology will take a few years to put in place, but the long-term impacts on water use could be huge.