May 30, 2020

The Main Act is About to Begin, But Lack of Radar Coverage is a Problem

As predicted, the second.....and probably more potent...line of thunderstorms is now moving northward near the Oregon/WA border.

The latest visible satellite image (4:26 PM) shows several major, strong convective systems entering Washington State.  The one on the right has good radar coverage from the Pendleton, Oregon NWS radar, but the western one is in the well-known radar hole over the eastern slopes of the Cascades.

The radar image at the same time (below), shows intense radar returns with the eastern storms (red colors), but the western systems have poor coverage so we don't know how strong they are.  Since they are heading for the Cascades and western WA, this is not good.

Over the past half hour, lightning sensors have shown massive lightning in these storms (see below, each strike is shown by an "X")

There are some strikingly strong winds with this line of thunderstorms, with some gusts reaching 60-70 mph! (see the max gusts over the past hour below)

Notable weather enthusiast, Dr. Peter Benda of Bellevue, went storm chasing in the Tri-Cities today, and the picture of the mammatus clouds beneath the anvil of the approaching storm is scary (see below)

And is another shot from Dr. Benda as the storm got close. Beautiful.  And you can see heavy rain falling out of the cumulonimbus.

And if you want to experience some of the strong outflow winds from the storm, check out the video he sent:

And there was hail with some of the more intense storms.  Here is a video provided by Pam Hayes showing the squash bass sized hail that hit around Tumalo, Oregon (just northwest of Bend) around 2 PM:

These storms will sweep northward during the next few hours.  Expect severe weather in the Columbia Basin and we will see how much of the action will get over the Cascades.  At the very least, the west side will have plenty of rain and some lightning.  The latest NWS HRRR forecast for 7 PM shows strong storms moving towards Ellensburg and Wenatchee, with others heading in the direction of Spokane, with light to moderate rain over the westside.  Without good radar coverage east of the Cascade crest, we won't be about to document the details there.

All Hell is About to Break Out

I will do an update at 5 PM...right before the big action hits....

Things are really revving up now.

The latest radar image (7:45 AM) shows a region of thunderstorms approaching Puget Sound and another storm over eastern Washington.  It is starting to thunder outside.

In fact, the latest WWLLN lightning network flash map shows LOTs of lightning south of Seattle and over the Columbia Basin.

And the latest visible satellite image is impressive with strong thunderstorms/convection on BOTH sides of the Cascades.

 The latest wave vapor satellite image is amazing.  In front of a deep low (red arrow) over southern CA a band of moisture and warmth is heading directly towards our region (blue arrow).  The fuel truck is here.   And uplift in front of the approaching disturbance is setting off the storms.

The NOAA Storm Prediction Center outlook has increased the threat of severe convection over our region to "enhanced."  This is quite unusual for us.

The really big action is later this afternoon and tonight...more on this later.

I am going to do a facebook live session at noon to talk about the can find it here:

May 29, 2020

Severe Thunderstorm Potential for Washington State

Portions of Washington State, particularly from the Cascade crest eastward, may see some very strong thunderstorms starting tomorrow morning and extending into the evening.    Storms that may bring heavy rain, hail, lots of lightning, very strong winds and even the chance of a tornado-packing supercell thunderstorm.

And western Washington may get some heavy rain and perhaps some thunder.

The NOAA/NWS Storm Prediction Center in Norman, Oklahoma has an unusual severe storm outlook for Saturday, with the greatest threat in central Washington and Oregon. You don't see that very often!

Key ingredients will be in place on Saturday in our region: very unstable air and an approaching upper level disturbance that will provide upward motion that will initiate the convection (thunderstorms).

To put it another way: we will have both the fuel (unstable air) and the match (the approaching disturbance).   And we will also have strong wind shear (wind change with height), which is important element for long-lived severe thunderstorms.

Tomorrow morning, the existence of a trough offshore and higher pressure inland, will produce a southerly (from the south) flow of warm,  moist air over the region (an upper level map for around 18,000 ft is shown below).  This will foster the development of instability AND strong wind shear--both important ingredients.

And to the south an intense upper low is lurking over California.  That feature...the match--- will move northward during the day and will initiate strong thunderstorms.    But there is more, this upper low will have a very strong low pressure center associated with it, and by 8 PM Saturday, the surface low will be positioned over eastern Washington (see below). Wow...there is a HUGE pressure gradient over central WA at this time....that will result in strong winds.

This evolution is going to produce extraordinarily unusual levels of instability in the atmosphere....the potential for the atmosphere to convect.  A measure of the potential for instability is know as CAPE (Convective Available Potential Energy).   Values tomorrow will be very high over eastern Washington, with some values getting about 2500 (that is very, very high for our region)....see forecast for tomorrow at 4 PM.

The UW high-resolution forecast model is predicting substantial precipitation over the region through 5 AM Sunday (see below), with much of western WA being drenched by .5-1.2 inches of rain.

And the UW model is predicting strong thunderstorms, something evidence in some of the cloud simulations shown below for 6 AM and 6 PM Saturday.  The white ovals are strong thunderstorms.  Huge.

The NOAA/NWS HRRR model forecast for 7 PM Saturday predicts some supercell thunderstorms with threatening hooked echos the Columbia Basin (simulated radar composite radar reflectivity is shown).

And I haven't even discussed the simulated winds, which gust to 60 mph near some of the forecast thunderstorms!  There will be blowing dust and potential fallen trees.

It should be an interesting day.

May 27, 2020

Stunning Satellite Image on a Nearly Clear Day

The new GOES weather satellite produces stunning images and today's pictures are particularly noteworthy. 

Here is an image at 1:26 PM today (Wednesday), showing off the full-color capabilities of the satellite.

The still considerable snow over the higher elevations of the Cascades really stands out, as does the glaciers/snow on the volcanic peaks and the Olympics.  Stunning.

And look closely at the image around Portland and northern Oregon.   A whole collection of jet contrails are apparent (see blow up below).  If we were in normal times, there would be a lot more of them.

Another thing that is striking is the huge amount of farmland in eastern Washington and northern Oregon, with much of it irrigated. Immense acreage.  And the irrigated areas actually cool the atmosphere because of all the water that is evaporated from the moist surfaces.

And finally, one can view the large amount of brown sediment around the Fraser River delta near Vancouver, Canada.

The imagery is particularly vivid because of the very, very clean air over us right now.  Take a deep can tell.  And the excellent quality of the air is reflected in the low levels of particulates , as illustrated by the PM2.5 levels at Aberdeen (on the coast), Seattle, and Spokane (see below) from the Puget Sound Clean Air Agency site.

Tomorrow will be nearly perfect across the region with mid to upper 70s across much of the State, clean air, and unlimited sun....enjoy.

May 26, 2020

Washington State Lacks a Rational Coronavirus Testing Approach: Can We Follow Oregon's Lead?

Washington State is in trouble.

Testing of coronavirus has stagnated and our current testing is being done in an uninformative, unscientific, reactive way.

We need not only to increase our COVID-19 testing, but importantly to begin random sampling of our population.  Embarrassingly, such science-based, rational testing is exactly what Oregon is about to start.

As stated by Oregon governor Kate Brown:
“This program is a game changer,” Brown said. “It will give us a more accurate understanding of the true rate of infections in Oregon and to have ongoing precision monitoring of any new outbreaks.”

Oregon is not alone.  Other states, such as Ohio and Indiana, are also doing randomized testing to understand the true state of the infection.  But not Washington.

Random sampling is the scientific way to deal with the COVID-19 crisis

Today, Washington State is dealing with the coronavirus pandemic in ignorance.  We are only testing those that have symptoms and ask for a test.  We do not know what percentage of the population is currently infected.  We don't know what percentage has been infected and thus might be immune.  We have no way to identify infected, but asymptomatic, people that need to be quarantined.

We are driving blind...and our state leadership doesn't seem to understand what needs to be done.

Scientists of all types (yes including atmospheric scientists) are well aware of the importance of random sampling to understand a population or system we are studying.  Pollsters use random sampling  for every election cycle.    But we are not even talking about doing it in Washington State when it comes to a fatal disease with vast economic implications. Why?

Our state leadership is throwing away a tremendous opportunity to defeat the virus.  If appears that random testing of a population is a powerful tool for keeping diseases like COVID-19 in check.  Several papers have shown exactly how this can be done.  One samples a few tenths of a percent of the population each day.  Such testing provide a good idea of the trend in infection.  But even more important, you can catch asymptomatically infectious folks and take them out of circulation.  If you have the resources, you can trace their contacts and test them as well.  Slowly, but surely you defeat the virus by quarantining the infected.

This approach, plus wearing masks in crowded indoor spaces and reasonable social distancing, might well allow us to reopen society much more quickly and extensively....and do so safely.

Not only is Washington State testing in an ineffective, unscientific way, but the number of tests is essentially stagnated, something evident from the statistics on the Washington State Department of Health website (below).  No increase in May.  Not good.  Massive increases in testing is needed, the lack of which is a failure on both the state and Federal levels.

This is a lot of talk about us being involved in a "war" with the coronavirus.  In that spirit, let's consider the military analog.

Consider two approaches for dealing with an enemy that is attacking and marauding the population of a nation.

One approach is to tell your population to hide in their homes and lock the doors, with the hope that the enemy will keep away.   Only when the enemy attacks does the military react by capturing and imprisoning the enemy. 

There is never an attempt to determine the strength of the enemy with surveillance  or to weaken the enemy by proactive raids.  The enemy, unmolested, retains their strength and the war drags out.  With folks stuck inside, the economy flounders.  This is how Washington State is fighting our war with Covid-19.

Another nation has a different approach. They start comprehensive surveillance of the enemy with armed scouting parties and overflights. They know exactly the strength of the enemy and where it is surging in strength. When they find the enemy preparing an incursion, they attack and take the enemy off the field.

Citizens are not told to lock themselves in their homes, but to go about their normal productive lives, but with care and watching for any trouble. They can do so, because they have confidence they will be warned if a threat looms. Slowly but surely the raids on the enemy weaken it and eventually they give up the fight. The nation's economy remains strong.

This is what Oregon, Ohio, and Indiana, among others, is going to do. What many municipalities and states are talking about doing. What Washington State should do. And yes, what the whole country should be doing.

But it is worse than that
. Not only is our state missing the boat on testing, but there have been a number o unproductive steps that are not based on science, such as closing parks, restricting the use of outdoor spaces, and promoting excessive lockdowns of the economy. 

As the economic toll becomes catastrophic, society will have no other option but slowly reopening. Random testing offers an approach to do so safely.

Here we have a state with unequaled scientific capabilities and knowledge, deep experience in data science and medicine, and unparalleled economic clout and we fail to follow an obvious, science-based path to opening our economy and loosening restrictions on our population. 
When considering anything dealing with conflict, it is often valuable to consider some of the wisdom of the Chinese military genius, Sun Tzu:

If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. 

Time to know our enemy.

May 24, 2020

What is the streamflow outlook for this summer?

Announcement:  I will be doing a short weather forecast followed by live answers to your questions on Tuesday and Friday at noon using Facebook Live.   This is an experiment to try to bring local weather lovers into a conversation, and I thought it would be good to provide some human interaction in this COVID days.  The session will be on my facebook page (


Streamflow....the amount of water moving down our rivers and streams.... is important for many reasons, ranging from water resources and flooding  to the viability of resident or returning fish populations.  So it is useful to check on the current situation and projections for the rest of the summer.

The streamflow today (see below) looks reasonably good.  Most streamflow sites are observing near normal conditions (green colors), with some locations (NE Washington, SE Washington) above normal (blue colors).    Only a few site in the south Sound are below normal. 

This relatively normal situation is the result of a near normal snowpack on April 1st (the beginning of the long "snow melt" season), and the bountiful rains over much of the reason during the past month.  To illustrate the latter, below is the percent of normal precipitation for the past month.  Well above normal over the eastern third of the State, around the Cascades, and over the southeast side of the Olympics. Far smaller areas below normal.

The NOAA/NWS River Forecast Center in Portland makes a streamflow forecast for 120 days (September 15th), at the end of summer dry/warm period.  The percentages of normal at that time (shown below) are, on average, roughly normal (100%), with higher than normal streamflows over southeast Washington, and near normal (green colors) over NE Washington, the Columbia River sites, and the northeast slopes of the Cascades.  Only the Yakima River sites are below normal.

The latter low streamflow is probably due to the lower than normal snowpack over those regions today as warm, downslope conditions caused faster than normal melting (see current snowpack below).
Fortunately, must of that melt water was captured by the Yakima River Reservoirs, which should be able provide water for both agriculture and fish during the summer (see below).   It is good to see that Yakima Reservoir levels are now above normal (blue is current, red is normal).

The bottom line is that at this point it appears that streamflow in Washington State rivers and streams should be near normal for most of the State and that some claims of drought and water shortages may not be well founded (see below).

May 22, 2020

What is the difference between partly sunny and partly cloudy?

Twice today I was asked about the difference between partly cloudy and partly sunny.   And that inquiry is one of the most frequent I get, for reasons I do not understand.

OK...let's settle this for once and for all.

Here is an image of a partly cloudy sky:

And here is an image of a partly sunny sky:

They are the same..... during the day, partly cloudy and partly sunny denote exactly the same thing:  a sky with between 3/8 and 5/8 coverage of clouds.   Obviously, partly cloudy would be a better choice at night.

Mostly cloudy  is 5/8 to 7/8 coverage, while mostly sunny indicates 1/8 to 3/8 coverage during the day.

Now, a harder one.   What does it mean to have a sky obscured?   Is it the same as an overcast sky?

The answer to the second question is NO--they are not the same.

The sky is obscured when you can not see the sky, when you are in middle of cloud or smoke or dust storm.  Here are two examples of an obscured sky, one from smoke and the other from low clouds/fog:

An overcast sky is when the entire sky is covered by clouds or smoke, but you are not in them.  You can see the base (bottom part) of the clouds or smoke.  Here is an example:

With this knowledge, you can amaze your friends at the next cocktail party.... whenever cocktail parties start again. 

May 20, 2020

The BLOB is Back! And it is Affecting our Weather!

With all the scary news these days, you need to be prepared for one more unwelcome announcement:  the BLOB is back and its impacts are already apparent.

Perhaps, you already know about our red menace, a large area of warmer than normal sea surface temperatures over the northeastern Pacific.  You can see the strengthening and extension of the BLOB in a series of temperature maps over the eastern Pacific, with the shading showing the differences of the sea surface temperatures from normal (yellow to red are above normal in degrees C).

During the last week in March, there was warmer than normal temperatures offshore, but near normal just off of the entire West Coast.
By late April, the warm blob had strengthened considerably, with an extension reaching the California/Oregon coast.

And last week, the warmth really surged up and down the West Coast, including off the Washington Coast, which was roughly 1-1.5C (2-3F) above normal

From past experience, we have learned that warmer than normal Pacific ocean temperatures tend to increase the minimum temperatures west of the Cascade crest.  If you are leaving in western Washington, western BC or western Oregon have you noticed the morning warmth?

If not, let's check it out!    Here is a plot of  the temperatures at SeaTac Airport for the last 12 weeks (red line), with the normal highs (purple line) and lows (cyan line) also shown.  During the past month, the low temperatures have rarely declined to the normal lows, being around 3F above normal.  You don't see that behavior back in March.
Quillayute, on the northern Washington coast, shows the same warm minimum...just more so.  That makes sense--it is right near the Ocean.
In contrast, moving over to eastern Washington, where the marine influence is weaker, shows far less impact of the warm water, as illustrated by the temperatures at Walla Walla.
As long as the BLOB-related warm water along our coast sticks around, our minimum temperatures each day will be several degrees above normal.  Being BLOB-savvy I took advantage of its moderating effects and put in my tomato plants early.  They are quite happy and growing well.

How long will the BLOB last?   That will be a topic of a future blog!

Thunderstorms Return to the Northwest

 Thunderstorms have been relatively rare this summer, but today will see some boomers over the Cascades and eastern Washington. In fact, the...