Darkness Descends On Washington State

One of the lesser pleasures of living in Washington State is the "return of darkness" during the autumn.   The rapid decline in solar radiation is particularly noticeable this time of year.

And it is not a little depressing for some.

Seattle at 7:45 AM Monday morning.

To illustrate, below is the solar radiation received at the surface at a Seattle location near the University of Washington (the WSU Ag Weather site) from late June until yesterday.  

You can see the steady decline over time of the sun's rays and the recent plummeting as clouds increasingly intercept the declining radiation due to the normal seasonal changes in meteorology.

Yesterday we dropped to about a quarter of the radiation of the peak in summer.  Yuk.

Richland, with fewer clouds, shows a lesser decline, but it is still significant.

To better appreciate why September is the most depressing month for sun lovers, consider a plot of the average incident solar radiation in Seattle (below).   The vertical red line shows today.   

Wow.  The sun's rays reaching the surface are RAPIDLY declining.... roughly half of the peak in late June/early July.

The situation in Richland, with fewer clouds and slightly farther south, is a bit better.

The key drivers in our loss of the warming rays of the sun include the changing sun angle (the sun is lower in the sky) and the rapid shortening of the day.

The graph below shows you the length of day (light blue) and night (black) in Seattle, with the vertical white line today.   We hardly have much night in late June, but it is RAPIDLY increasing right now.

Just depressing.

The extreme seasonal variation in solar radiation in our region....both astronomical and meteorological...  has a lot of implications for solar energy and a reason why solar energy is really not a viable source in our region for much of the year. 

Let me illustrate with some official NREL solar energy graphics.  

For July, there is plenty of solar resource for the Northwest, particularly for Oregon and easterly Washington.  

September is still a viable month for solar radiation over the Columbia Basin and eastern Oregon, but things are rapidly going downhill in western Washington.  

 

By December only the southwest US and perhaps the southeast US are viable for significant solar production.

So if you are living in Washington State, time to think about the purchase of a sun lamp, and if you have the cash, a trip to a sunnier location during mid-winter.   No wonder Alaska Airlines purchased Hawaiian Airlines. 

Washington State Had a Very Low Wildfire Year

In contrast to the warnings by certain media outlets and others, this has been a very benign wildfire year for Washington State.

Less fires than normal, less area burned than normal, and far less forest area burned than normal.

Consider the statistics provided by Washington State Department of Natural Resources, whose area of evaluation only includes DNR lands (see their map of wildfires of all sizes this year).

For these DNR lands, this year has fewest number of wildfires over the past ten years (see below), well below normal  (red dotted line).

Most of the wildfires are very small, many being debris/garbage burns gone out of control.  More important is the area burned, whose statistics are shown below.  Only a small area burned this year...about half of normal (red line).

What is particularly striking this year is how little forest area has burned in Washington, with most of the burned area being grass or rangeland (or places where rangeland interfaced with low-density forest).

To illustrate this, below is a map of the burned area this year so far.   The biggest fire was a range fire near the Columbia Gorge.  Most of the others were primarily in range/grass, with minor tree components.

It is of interest to compare this year's fire areas against the fire areas for the past decade below).  Grassland/range areas dominated but there were certainly some significant forested areas that have burned.

Air quality was generally decent over western Washington this summer, with most the smoke remaining aloft when it did enter the region.   Below is the small particle concentrations (PM2.5) at several locations around Puget Sound.  A few minor events.  The worst air quality was associated with July 4th!

Finally,   I may be sounding like a broken record, but the hype of this wildfire season for our state, pushed by local entities such as the Seattle Times, was not responsible.  The ST "Climate Lab" is infamous for this kind of "journalism".

The truth is that the last few years has seen only modest wildfire activity over Washington State.

The truth is that nearly all the fires are caused by human ignition.

The truth is that most of the fire areas have been characterized by grass and range vegetation, or places where such light fuels impinge on areas with trees.   Fires in light fuels have little to do with climate change, since they can dry out within hours.

The truth is that there has been massive increases in human settlement in fire-prone areas.

The Autumn Transition

Nearly every September has a transition to fall-like weather, with no going back.  We are in such a transition right now.   

For Washington State, regular rains will return, 80s and 90s will be memories, and the wildfire season will be over.

Before I show you the forecast, consider the climatology of this month. 

For temperature, September average maximum temperatures at Seattle (thin red line) goes from the summer-like mid-70s to the mid-60s (the vertical red line shows today).  No more 90s by the end of the month.  Ever.

For the probability of measurable precipitation, there is only small upward trend after the typical "moistening" of late August.

But there is an interesting quirk I have noticed: we often get a decent shower mid-month.  Take a a close-up view of the precipitation climatology below:  you can see the mid-month rain spike.  Buy why?

Enough climatology.....let's consider the forecast for the next week or so.

The temperature forecasts for Seattle and Pasco predict autumn-like conditions.

Seattle will stay with fall-like 60s for the next ten days.

Pasco, in the Tri-Cities, drops into the 70s and stay there.

And yes, there will be regional rain that will end any talk of wildfires from the crest of the Cascades westward.

The predicted rainfall total though Tuesday (below) forecasts light to moderate precipitation from the Cascades to the Pacific, with substantially higher values over the Rockies.  Importantly, fire-prone eastern Oregon shares in the moisture.

The next 96h (through Thursday morning), more of the same if not a bit wetter.

The reason for this switch to a wet-cooler situation is because a series of upper levels will develop over or move into the West Coast, something illustrated by the upper-level (500 hPa, about 18,000 ft) weather map for Sunday afternoon.

Enjoy the fall weather.  Our plants will be happy and the smoke aloft should rapidly become history.

Is Hawaii Prepared for the Next Wildfire Event? I Worry That the Answer is No.

Just over a year ago, western Maui was hit by a powerful downslope windstorm that initiated a wildfire that destroyed the historic town of Lahaina.

Lahaina after the August 8-9, 2023 fire

A terrible tragedy that cost the lives of approximately 100 people and resulted in roughly 4 billion dollars of damage.

Hawaiian Electric, local government, and others have taken some steps to prevent the tragedy from reoccurring.  Unfortunately, for the reasons outlined below, I worry there are gaps in their efforts that could lead to a repeat of the terrible disaster of August 2023.

Examining the Meteorology of the Lahaina Event

I do a lot of research on the meteorology of western U.S. wildfires, and particularly wildfires associated with downslope windstorm events, which characterize the 2023 Maui wildfire.  I received a grant from the National Science Foundation to study the meteorology and predictability of the Lahaina event, and after some intensive work with research meteorologist David Ovens, published a paper on the subject.

There were several significamt findings of the paper:

1.  The wildfire was associated with a strong downslope windstorm, which damaged powerlines starting the fire.

2.  The event was highly predictable up to approximately a week ahead using high-resolution model forecasts.

3.  The observational network on Maui and the rest of the islands was very poor.

4.  There were multiple levels of failure by Hawaiian Electric and public authorities.  Furthermore, the National Weather Service never highlighted the particular threat to Lahaina even though its high-resolution model (HRRR) clearly predicted the strong winds (see below)

The NWS HRRR Model

Hawaiian Electric's Attempt to Deal with the Threat

During the last months, Hawaiian Electric announced its response to the wildfire threat.  

First, they are adding several dozen new weather stations around the island, particularly in observation gap areas.  For example, there are now observations near Lahaina, where none had existed before (see current map below).  This is good.  But there are still major gaps in the observational network.  Furthermore, surface observations tell you what is happening NOW, not what will happen in the future.  And to save lives and property, forecasts are critical.

Finally, there is a lack of upper-air observations, which are critical for forecasting (more on this later).

Current Real-Time Surface Weather Observations on Maui

Second, Hawaiian Electric plans to harden and modernize its distribution network, much of which is outdated and below modern standards for robustness to strong winds.  Commendable and high priority, but will take years to complete.

Third, Hawaiian Electric plans to start doing Public Safety Power Shutoffs (PSPSs) when threatening conditions are expected, not unlike what has been done by California utilities.  Its a way of dealing with deficient power distribution network surrounded lots of flammable fuels.

Unfortunately, there are weaknesses in their plans for PSPSs.

According to Hawaiian Electric documents, their decision to initiate a PSPS will first depend on observations (identifying persistent drought conditions, wind gusts of 45 mph and more, relative humidity below 45%).  That is a good start, but reacting to observations is not good enough.  Winds can increase suddenly.  People, businesses, and others need more time to prepare.

Hawaiian Electric states they will use National Weather Service (NWS) public forecasts, but that is not good enough, something highlighted by the relatively poor performance of NWS predictions during the Lahaina wildfire.  During that event, the NWS failed to highlight the great threat to Lahaina.  Instead, the NWS put out a broad-brush red flag warning for the lee side of all the Hawaiian Islands.  Not good enough.

Hawaiian Electric needs to use high-resolution numerical model forecasts for their decision making including PSPS declarations.

There are a variety of ways Hawaiian Electric can secure such model predictions:

1.  Run the models themselves, which is what California utilities  (e.g. PGE) are doing.

2.  Use the NOAA/NWS HRRR-Hawaii model, which is run regularly in "experimental" mode.  This is totally silly by the way....NOAA/NWS needs a hardened, high-resolution operational model for Hawaii.

3. Hawaiian Electric should use the high-resolution regional weather prediction made by the University of Hawaii Manoa.

Hawaiian Electric also needs to have a team of meteorologists constantly monitoring both the observations and high-resolution model forecasts.  I don't thing they have any at this point.

They also should talk to the USDA Forest Service to give Hawaii critical wildfire weather diagnostics enjoyed by the rest of the U.S., such as the valuable HOT-DRY-WIND diagnostic.

Better Observations Aloft of Hawaii

To forecast and diagnose downslope windstorms.... the key driver of catastrophic wildfire on Hawaii, one has to know the structure of air approaching the islands through the depth of the lower atmosphere.   Right now Hawaii has such information only twice day at two radiosonde locations:  Hilo and Lihue, which weather balloons with instruments are launched twice a day (see stars on map).  Not good enough.

Hawaiian Electric, the State of Hawaii, and the Federal Government need more upper-air observations for the islands.  One approach is to add another radiosonde unit, with more frequent vertical soundings.  Or Hawaii could secure some vertical profilers, devices that sense the atmosphere remotely (see below).   The West Coast has many of these devices, why not Hawaii?

We Can Prevent Hawaiian Wildfire Disasters

The disaster in Lahaina last year was preventable.   Weather modeling and observational capabilities have improved so dramatically that we can foresee such events with great clarity and skill, allowing an effective response that will minimize loss of life and damage.  Hawaiian Electric and Hawaiian governmental entities must use these tools to prevent another tragedy.

Oregon Smoke over Washington. Ends Monday.

 The visible satellite image this morning shows a plume of smoke over Washington, smoke that mainly originated over eastern Oregon.

The effects of the smoke were pretty obvious over western Washington, with an attenuated, red sun rising to the east this morning:

The smoke is thick enough that the intensity of solar radiation has decreased noticeably (see measurements at Seattle below for the last three days below).   That means we will be cooler today as a result. 

Air quality is good on the coast, moderate over the western lowlands and the Columbia Basis, and poor over sections of eastern Oregon

The laser ceilometers run by the Puget Sound Clean Air Agency clearly show the smoke moving in aloft.  Here is an example from the instrument at  Beacon Hill, Seattle. The time is on the x-axis (increasing to the right) and the y-axis is height in meters (3000 meters is about 10,000 ft).  Quite a deep layer of smoke is moving through overhead.

.   

Nearly all the smoke is coming from extensive fires in grass, bushes, and scattered trees in eastern Oregon (see current fire areas below).  Numerous lightning and human-ignited fires have occurred in the rangeland of eastern Oregon, with other fires over the southern Oregon Cascades.   The extensive, lush flammable invasive grasses (like Cheatgrass) are a real problem.

For most of the summer, the smoke from the fires did not influence western Oregon or Washington because winds generally move from west to east in our region.

But during the last few days, easterly winds have prevailed, associated with a thermal trough extending into western Oregon.     To illustrate, here is the forecast weather map at 850 hPa (about 5000 ft) this morning.  The solid lines are like pressure and you can see the wind symbols.  Easterly winds over northern Oregon and southern Washington.

Below are  the air motions at the same level (5000 ft) ....something called streamlines.   You can see why the eastern Oregon smoke is approaching us.

Fortunately, the situation is going to change during the next 36-48 hours.

Here are the streamlines showing airflow at 5 PM Sunday.  The wind direction has radically changed...now out of the Northwest.  That will blow the smoke away.

To show the improved smoke situation, let me display the smoke forecast (total in a vertical column) from the highly skillful HRRR smoke prediction model.  

This morning at 8 AM. Lots of smoke.

Tomorrow morning at 7AM, still smoky.

But by 5 AM Monday morning, the switch to northwesterly flow was doing its magic, with western Washington nearly clear of smoke.   Tuesday will be even better.

Relief is on the way!

Superinversion on the Hottest Day for the Rest of the Year

 An inversion is when temperatures increase with height.  

Today a super-inversion exists, with extraordinary warmth aloft.

At 6 AM this morning, temperatures are in the lower 50s in the south Sound and upper 50s to around 60F in central Puget Sound (see map).  But looking to the western Cascade slopes, you see some warmer temperatures with some in the low 70s.

It was so chilly at local river valleys that fog and low clouds formed in some of them:

But now, let me shock you.  Right above Puget Sound, just a little over a thousand feet up, the temperatures are in the 80s!   

You heard that right.   In a few hours, that warm air will mix to the surface and high temperatures will climb into the the upper 80s to near 90F over the western lowlands.

The warmest day for the remainder of 2024 will occur today

Below is the temperature structure at 6 AM from aircraft data at SeaTac Airport.  Around 63F at the surface (452 ft ASL) and 80F at around 1600 ft.  AN INCREASE OF  17F in around 1000 ft. 

 Mama Mia...that is an inversion!

Can you imagine hiking up a local peak, such as Tiger Mountain, this morning?  You would hike from 55 to 80F within 30 minutes.

The sun will warm the surface today causing increasing vertical mixing.  Rapidly, the warm air aloft will be mixed down to the surface and lowland temperatures will surge.  

The UW high-resolution ensemble of many forecasts (below), suggests a high around 90F at SeaTac, with cooling over the next several days.

And there is one other thing. Smoke.

The wind pattern aloft will move some of the smoke from fires in central Oregon into western Washington.  In fact,  you can see the smoke on a visible satellite image earlier this morning:

As the atmosphere mixes vertically today, some of that smoky air will be mixed down, mainly over SW Washington.

Finally, let me give you some good news. The National Weather Service has a red flag warning out for the western slopes of the Cascades (see below).   

Fortunately, this is little chance of western slope wildfires today and particularly spreading wildfire.  Why?  Because strong easterly winds are not forecast today.  Major wildfire events require wind and western Washington wildfires require strong easterly winds.