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.
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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.
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.
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.
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.
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)
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).
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.
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.
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.
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.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.
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.After examining a wide variety of forecast models and considering the region's climatology, it appears we will have to endure only one more warm spell for the remainder of the year.
And by a warm spell, I mean an event where western Washington rises into the mid-80s or above and eastern Washington nears 100F.
I will start by showing you the forecasts.
At Seattle, the skillful NOAA/NWS National Blend of Models (NBM) prediction system forecasts warming to the mid-80s on Thursday and Friday before cooling over the weekend. Temperatures cool to below normal (upper 60s) next week. The average high-temperature today in Seattle is 75F for reference.
As a check, consider the highly skillful European Center model ensemble of many forecasts (the mean of these forecasts are shown below). Quite similar to the NWS prediction.... and this forecast extends through mid-month.Next moving to the Tri-Cities, the prediction for Pasco shows a torrid high above 100F from Thursday to Sunday, with cooling to the lower 80s next weekSo enjoy the heat, wear some shorts, and get that swim in. The heat will soon be over and we will be moving towards fall-like weather starting next week.
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Reminder UW students: I will be teaching Atmospheric Sciences 101 this fall:
In contrast to the warnings by certain media outlets and others, this has been a very benign wildfire year for Washington State. Less fires ...