Why the Washington Drought Emergency Should Be Dropped Immediately

It is time to clear the air.   

To definitively correct misinformation being pushed by a Washington State agency, the Seattle Times Climate Times Climate Lab, and some amateur YouTube channels.

The claim that this summer represents a DROUGHT EMERGENCY for Washington State.   

It is simply and demonstrably false.

In a previous blog, I showed that our reservoirs are fuller than normal, soil moisture levels are good, our annual precipitation is at or above normal, and that current crops are doing well. 

But like some vampire, the drought claims can not be killed so easily.   

In particular, the media, YouTube amateurs,  the State Department of Ecology, and others are pinning their drought claims on the Yakima River drainage and this year's low snowpack.

Below, I will demonstrate why they are very much wrong. 

Yakima and Kittitas counties, through which the Yakima River flows, are relatively arid locations, being located in the rain shadow of the Cascade Mountains (see below).

Only with substantial irrigation can they provide the agricultural bounty for which they are well known.

This irrigation comes from two sources.  

Much of Yakima and Kittitas agriculture gets its water from the Yakima River, with some contributions from the Columbia on the eastern side of the area (see map below).   Everyone agrees that the Columbia will have plenty of water this year, so there is no suggestion of drought for the majority of the irrigated land in eastern Washington (blue, purple, and yellow colors below)

The Yakima River drains off the Cascades, starting near Snoqualmie Pass, and is also fed by a few tributaries, such as the Cle Elum, Teenaway, and Naches rivers.

These rivers are mainly fed by mountain rain and melting snow.  Since most of the precipitation falls in winter and spring, while most of the irrigation demand is during the dry summer (particularly July and August), water storage is required.

One source of storage is the Cascade snowpack, which does most of its melting in May and June.  Thus, snowmelt is only a short-period source of water... a fact that will be important later.

And then there are the Yakima River Basin reservoirs (see below), which are filled by both rainfall and snowmelt.

And finally, there is spring and summer rainfall, which is modest in this region.

To fully supply water for all agricultural and human needs of the Yakima irrigation district requires about 2.3 million acre feet for April through September.    The reservoirs can hold about 1.1 million acre-feet, or roughly half what is needed.

The remainder must come from the river flow, supplied by either mountain rain or snowmelt.   

A big issue is timing:  only the reservoirs can supply a large amount of water during mid-summer (July and August) when demand is greatest.  

Keep this fact in your mind...it is crucial.

Now, let's consider the water situation this year.   The annual precipitation was actually wetter than normal over and near the Cascades (see difference in normal during the water years from October 1 to  May 6, below).  So plenty of water falling from the sky.

But much of this precipitation was associated with warm atmospheric rivers and substantial amounts fell as rain, particularly at lower to middle elevations.   Particularly strong atmospheric river events occurred in December (which produced substantial flooding) and March.

Because of the warmth of those atmospheric rivers, the snowpack was below normal this season over the central and southern Cascades, with the Yakima Basin topping out at around 50% of normal (see below).  Not zero, not 20%.   This is going to be important as well.

The substantial precipitation and the wise actions of those running the Yakima reservoirs have led to the Yakima reservoirs filling well in advance of normal.   Filling early without the need for snowmelt.    

Check out the figure below, which shows the water storage this year (blue line) compared to normal (red line).  Stunning.  We are already above the normal mid-June peak!

The Yakima Reservoir storage will remain topped off for several more weeks.  Why?   There is still considerable snow left to melt at higher elevations in the Cascades during the next week or so (see below).

.And the current model forecasts indicate substantial precipitation over the region next week (see totals through next Saturday).

There will be plenty of precipitation and snowmelt to keep the Yakima Reservoir system topped off through the end of the month.  No drying heatwaves are forecast during this period.

With Yakima Reservoir full in early June, there is a near certainty of sufficient water for Yakima County agriculture this summer.

I am not speculating....I checked.   Full reservoirs starting the summer are associated with ample water for agriculture in Yakima and Kittitas Counties.  There have been no examples of serious agricultural water issues for years in which these reservoirs start off the summer full. 

So how could the Department of Ecology and others get this so wrong?

They did not consider several unusual aspects of the past year.   

We started off with very low river and reservoir levels last fall.  But then we had crazy heavy warm rain in December, which caused a massive increase in river levels on both sides of the Cascades.   To illustrate, the figure below shows the flow on the Yakima River at Umtanum over the past two years (see below, black line).  Then, in March, another major event occurred.  Both were at record levels (dark blue lines)

Knowing about the low snowpack, the Yakima system water managers saved a portion of the huge influx of water,  pushing storage WAY above normal.  Very wise.

Normally, some of the melting snowpack is used to fill the reservoirs, but because of the heavy rain, it was not needed.   Thus, the melting snow could be used simply to keep the reservoir topped off and support reasonable flows.   

Because of the above-average precipitation last winter and the full reservoirs, we did not need to have a normal snowpack this spring..... 50% could do.   And the substantial rain also provided soil moisture west of the Cascades.

Those falsely calling for a drought emergency love to note that reservoirs can only hold about half the needed water for Yakima irrigation, and thus, they suggest that we need 100% snowpack to get through the summer. 

False!

But they are thinking too simplistically.  During the spring and early there is still substantial precipitation and water draining into the system, providing water for irrigation and other uses.  And we never use 100% of the snowpack water, with substantial amounts running into the sea.   Don't believe me?  Here is the average flow at the Dalles on the Columbia River.

A snowpack with 50% of normal snow still has a LOT of water.

In summary, the Drought Emergency Declaration by Washington State should be dropped immediately.  

Washington State residents deserve accurate information.  Washington agriculture should not be undermined by ill-advised, unscientific declarations.

Funnel Cloud in the Lowlands and Substantial Snow in the Mountains

Very active spring weather has been occurring over the Northwest, with substantial snow above 4000 ft and unstable air that has brought heavy showers and even a mini-tornado!

First, the snow.   Here is a cam shot this morning at Paradise (Mt. Rainier) at around 5400 ft.  Impressive snowfall!

Hurricane Ridge on the Olympic Mountains (around 5200 ft).  Beautiful

Even the relatively low elevation of Stevens Pass (around 4000 ft) received significant snowfall.

All of this white bounty is the result of very cold, unstable air moving into our region, which is illustrated by the visible satellite image this morning (below). 

The blue arrow points to the unstable air, characterized by showers and sunbreaks.  The instability showers are driven by a large change in temperatures with height, with cold arctic air passing over relatively warm water.

Since current, low-level winds are from the west, there are rainshadow regions downstream of the Olympics and Cascades (areas of lack of clouds are evident there).  

Substantial new snow has been falling above 4500 ft, such as at Paradice on Mountain Rainer, where nearly 15 inches have fallen (see below)

Precipitation over the region during the past 48 hr has been substantial, with many locations in the mountains getting 2-3 inches of liquid water (the observations are shown below).

As I have discussed in previous blogs, the claims of extreme drought over the region are inconsistent with the facts on the ground (and in the air).    There will be plenty of water this summer for all uses,  particularly with the full reservoirs of the region.  

Snowpack was low, but substantial, and well-timed total precipitation (which was NOT below normal) ensures that water will not be a problem this summer.

Now for the fun part of the blog.....we had another funnel cloud over Puget Sound....a mini-tornado if you like.

One formed yesterday (Friday) over southwest Seattle around 8 PM.    The rotating cloud was captured by Matt Young, a relative of one of my colleagues at the UW.

This weak tornadic event was associated with a modest area of convection (cumulonimbus clouds), which is apparent in the radar image around 8 PM (below).

Funnel clouds associated with weak cumulus convection (produced by unstable air) are not unusual over Puget Sound.   There is a lot of horizontal wind shear around here (winds changing rapidly in distance), with wind shear having essential rotation (see schematic below).   

The upward motion in convection can "spin up" this rotation into a weak vortex....something I have blogged about many times before.

Puget Sound Convergence Zones are famous for being associated with such weak funnels, something I describe in my Northwest weather book.

Puget Sound is not Oklahoma, where several thunderstorms and tornadoes are frequently threatening.  But weak convective funnels occur all the time around the Puget Sound region.

Snow in the Mountains and Wet

The rapid transition to cool, wet conditions occurred yesterday, with temperatures in Seattle declining from 80F on Tuesday to 58F in Wednesday.   Major cooling.

Cool and wet enough so that substantial snow fell above 5000 ft (see Paradise and Crystal Mountain cam imagery below).

During the past 48 hrs, there have been large amounts of precipitation in the Cascades, with one location near the Spada Lake reservoir getting almost 4 inches!  Lots of precipitation to moisten the crops in eastern Washington.

The cool/wet weather is not over.  A very potent front is now approaching our coast (see current satellite image below).  Cold/unstable air is behind it (area with clouds and openings on the left side of the image).

Below is the forecast precipitation total through Sunday morning.  

Substantial amounts (1-4 inches) on the western side of the Cascades and near the crest.  Substantial amounts on the SW side of the Olympics.

Temperatures will be low enough that substantial snowfall will occur above 5000 ft (see below).

This precipitation is very well timed and will push up river levels on the eastern side of the Cascades, which have been lagging due to below-normal snowpack (see below for the Yakima River)

The fact that the Yakima Reservoirs are now full and will remain full for the next several weeks bodes well for the water supply this summer. 

"Perfect Storm" Rainfall Comes to the Northwest

It has happened multiple times this past year.   

After an extended dry period, the circulation pattern changes, bringing wet conditions that get us close to normal again.

This is going to happen again starting tomorrow. 

The predicted accumulated precipitation through Thursday afternoon will be substantial in the Cascades, and even eastern Washington will enjoy a general moistening. (see below)

Importantly, the precipitation will continue!  By Sunday afternoon (below), some locations in the Cascades will enjoy 2-4 inches.  This will cause rivers to substantially rise on both sides of the Cascades.

Temperatures will dramatically cool for the remainder of the week....with highs declining to around 60F over the western lowlands (see below).

Cool enough that snow will fall at higher elevations (see below)

The storage for the Yakima River basin has remained full (see below).  This wet/cool period will guarantee it remains high for the remainder of the month. 

River flows are below normal because of the lack of snowpack, but flows should be close to normal after mid to late June when reservoir releases are dominant.

The precipitation and relatively cool temperatures will ensure that soil moisture remains in good shape (currently, 78% of the area is adequate)--see below:

If any of you were considering planting seeds or plants, THIS IS THE TIME TO DO IT!  Soils have warmed, and precipitation will keep the ground moist.

Substantial Precipitation Will Soon Return to the Pacific Northwest

For those worried about Pacific Northwest drought, I have some news that should give them substantial comfort: substantial rain and snow will return to the Pacific, accompanied by cool temperatures.  

And not a hint of any heatwaves.  In fact, much cooler temperatures are expected.

So get your rain jacket out of the closet, get ready to plant some seeds,  and think about delaying that late-May hike.

Let's start with the best, the European Center model forecast for precipitation over the area (below).

The expected precipitation through Wednesday afternoon starts the wetting process:

By Sunday evening, all the mountains will be thoroughly moistened.  

But there is more!  By the morning of Monday, May 25, the totals are impressive, with some mountain locations exceeding 4 inches.  Even rain in eastern Washington.  This is serious precipitation.

Importantly, temperatures will cool substantially over the next week, so there will be substantial fresh snow in the Cascades (below).   Expect the % of normal snowpack to rise substantially from this late-season snow.

So what is going on?  

With the change in season and the transition from La Niña to El Nino, the upper- level pattern has unlocked, and some strong troughs of low pressure will be moving into the Northwest.  

To illustrate,  below is the forecast upper-level map for Friday morning.  An impressive trough of low pressure (blue colors) will build off our coast.

A week later, ANOTHER strong trough is forecast....winter-like in intensity in a similar position.

Other modeling systems (like the NOAA GFS) are doing similar things.   

Extremely favorable and well-timed for Northwest agriculture and local water resources.

Major Forecast Failure

Weather prediction has become hugely more skillful during the past several decades, but there are still some failure modes.

This week in western Washington, we had a master class in forecast failure due to our local weather nemesis:  low clouds.

On Monday afternoon, the National Weather Service forecast for the high temperature in Seattle on Tuesday was 76F.   For Wednesday afternoon, 72F (see below).

The actual highs?  66 F and 57F.  

HUGE errors on the cold side (10F and 15F!)

Instead of a continued warm period, temperatures were well below normal (see a comparison to climatology below).  The brown color shows the normal range. 

The vaunted UW high-resolution ensemble of many model forecasts at Seattle (below) was highly accurate on Monday, but too cool on Tuesday and Wednesday (yellow dots are observations).

In contrast, forecasts of the National Weather Service and the UW model for the Washington Coast and Eastern Washington were excellent.

So what is going on?   

This event (and others like it) demonstrates a great weakness of most weather prediction systems:   an inability to predict or maintain a cool, shallow cloud layer.

Most models tend to produce too much low-level mixing, which destroys shallow, cold, saturated layers.

Let me show you the proof.  

There are visible satellite images for 2 PM on Tuesday and Wednesday.  Lots of low clouds over the western lowlands.  Clouds associated with cool surface temperatures.

In contrast, the predicted clouds, the UW WRF model, or the National Weather Service GFS models had no low clouds over western Washington.

Several of us are working on this problem, but in the meantime, either the National Weather Service forecasters need to more actively intervene in the forecasts, or we need to more effectively apply statistical corrections during these low-cloud periods.

This is a serious problem for Western Washington since low clouds are quite frequent during late spring and early summer.

June Gloom Comes Early

It is the transition that Northwest residents both expect and regret:   the intrusion of low-level stratus clouds into western Washington and Oregon. 

Usually occurring in late May, this year the transition came a bit early, with cloudy skies the rule today and yesterday over the western lowlands.

Below is the visible satellite image this morning.  The low clouds are stopped by the higher Cascades, and the Olympics are an island that extends above the clouds.

As an aside, the heavily irrigated eastern Washington is a sea of green.

The Seattle Panocam was well into the murk this morning (see below), and at my home in north Seattle, there was drizzle from the low clouds.

Yesterday was similar, and the high temperatures at many locations were below normal....the short heat wave is over!

As normal during our late spring June Gloom periods, the entire eastern Pacific is full of low clouds (the visible satellite image this morning is shown below)

The cool, moist marine air is only a few thousand feet deep, as shown by the temperature and dewpoint sounding at Forks, on the Washington Coast (red is temperature, green is dewpoint).  

When temperature and dewpoint are the same (in the lower portion of the sounding), the air is saturated...which means clouds!

Also note the strong inversion...temperature warming with height--above the cool air.  This inversion acts as a stable layer that prevents mixing of the low-level cool air into the atmosphere above.

Why do low clouds form in spring over the eastern Pacific?

Because of high pressure building aloft.  The weather map showing 500 hPa pressure (about 18,000 ft) for 11 AM this morning is shown below.

And at the surface:

Low-level high-pressure offshore pushes cool marine air into the westerm lowlands.  High pressure aloft creates upper-level sinking, which warms the air aloft.  This warm air creates the inversion that prevents the cool marine air from mixing with the dry air aloft.

We get stuck in this pattern for days or weeks this time of the year.   A good time for meteorologists to go on vacation.