The weather story of the week in Connecticut, and perhaps the year thus far, seems to have come out of nowhere. The story however, begins last month.
One thing that is important to keep in mind is that wildfires are normal. In the natural order of our planet, wildfires bring balance to ecosystems and create the environment necessary for new growth. In fact, according to the National Park Service, it was the 1960s when policies changed to manage and mitigate wildfires rather than attempting to prevent every fire.
The Origin
The aggregate of the ongoing fires in Canada are far from normal.
According to statistics from the Canada Interagency Forest Fire Centre, the last week has seen three times more square kilometers burned than Canada sees during the first five months of a normal year.
It is not hyperbole: Canada is experiencing an unprecedented amount of wildfire activity so far this year. Back in May, many of these fires were concentrated in western Canada. With the jet stream, smoke from those fires were carried over the region but at high altitude, allowing for air quality levels to remain good generally through New England. This is how a lot of our "smoky" days are. Western wildfire smoke reaches the region at high altitude, and sometimes it comes in lower, impacting air quality.
Given the distance of the fires, the concentration of the smoke is often less even when the smoke is lower in the atmosphere.
However, in recent weeks, Quebec and eastern Canada have seen a dramatic proliferation of fires. As of earlier this week, over 160 fires were active in Quebec province alone, and almost all were out of control.
This is where the broader upper level pattern factors in.
Generally, the jet stream allows for a west to east flow that keeps things moving. This is also important to the environment, as it allows for the consistent movement of heat and moisture. You don't want it to be too sunny or too rainy, because one brings drought and the other brings flooding. Balance is the key.
We're in an Omega block pattern. This isn't a new term or feature in meteorology. Omega blocks happen around this time of year as the seasons transition, and it is named after the Greek letter--it's not an innately ominous weather feature.
Essentially you get a significant ridge bookended by significant buckles in the jet stream, creating a much "slower" pattern. On the sides of the the ridge you have low pressure areas that in the slower pattern are slow to move. That's exactly what we have here, with a Midwest ridge and cutoff lows on the west coast and east coast. A massive ridge over the west in May (another Omega block) is part of the reason we see so many wildfires out in western Canada, which had its warmest May on record, and we had our sunniest May since at least 1940.
How does this impact us? The circulations of the ridge and upper level low on the east coast have created near perfect air flow from Quebec, carrying smoke into the region.
If wildfires are normal, it stands to reason that smoke intrusions happen as well. Even in New England. That is true, and from time to time we do end up with lower air quality due to wildfire smoke from the west or north, especially in the summer. In fact, just a few years ago we had a few significant smoke days.
So why is everyone talking about this? You probably feel it intuitively from a cough, headache, or fatigue in the the last 36 hours, or perhaps you've seen the incredible images in your community or of New York City: this smoke intrusion is much different.
First, the depth of the smoke is rare. Looking at the visible images from the last two days, you see dark plumes of smoke over the region. This shows a very high concentration of smoke. This has led to an extraordinarily high amount of pollutants to enter the region at ground level. What was bottled up in Canada is being released over the region. We even saw ground stops reported at the New York City airports today.
Second, the duration of a smoke intrusion of this magnitude is uncommon. This is the second consecutive day where parts of the region has had some of the worst air quality on Earth. With the Omega block in place, more smoke is likely the next few days, even if it is not at the same intensity. Where the worst ends up however is based on wind direction.
To further contextualize, we do have bad Ozone days. They are far less frequent than they used to be looking over 40 years of data. Smoke is different, however.
Looking at EPA data across Connecticut going back to 1999, this is the worst smoke intrusion since July 7, 2002. It's harder to find specific PM2.5 data before that.
This intrusion is far worse than that, as my research has shown much higher concentrations of PM2.5, the smallest pollutant particle which is often considered most dangerous.
Unlike heat, or cold, or snow, or rain, this concentration of pollution impacts everyone negatively. Your age or physical condition do not matter, as PM2.5 are particles 2.5 microns or smaller. They have negative health effects, as many followers have reported since the smoke intrusion began.
Today looks like the peak, thankfully, but Thursday and maybe even part of Friday may be unhealthy as well.
In sum, while smoke intrusions happen, even bad ones, this is in my opinion the worst in at least a generation.
June 7, 2023
We need the Omega block pattern to change to end. Unfortunately, it is going to take a little time.
Tomorrow as it stands does look a little better than today, but air quality still doesn't look great. Friday is looking better, but as you can see on the HRRR there may be smoke coming in from the south on Friday as the upper level flow begins to shift.
The weekend is looking a little better, but at this time I think it's best to take smoke forecasts day by day in case things change.
Hang in there. This will break eventually. In the meantime, unfortunately, we have to turn to the experts, the California Air Resources Board, on how to protect yourself from wildfire smoke.
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Thank you for reading SCW.
-DB