The West hasn’t totally cooled off, but the region has gotten a slight reprieve from the heat that has dried up reservoirs, curtailed hydropower, and otherwise wrought havoc on the megadrought-afflicted region. Unfortunately, all good(ish) things must come to an end.
The National Weather Service is warning of a “Record-Breaking and Dangerous Heatwave” hitting this weekend and early next week. Weather models are also coalescing around blistering heat. If the forecasts come to fruition, we’re not just talking about a few daily records falling here and there. We’re talking about a heat wave for the ages that could absolutely destroy all-time records from Washington to California as well as parts of Canada.
In what’s becoming an all-too-familiar pattern for those in the western half of the U.S., high pressure is expected to move in and park itself over the region in the coming days. That will usher in sunny skies and allow heat to start to build. By Sunday, a region from the Yukon to Southern California could see temperatures well above normal. The bullseye of heat will center on the Pacific Northwest where temperatures could be an eye-watering 40 degrees Fahrenheit (22 degrees Celsius) above normal.
The Euro and GFS weather models, essentially the two gold standards for forecasters, are in agreement that the magnitude of this event will be extreme. While there are some slight differences of a few degrees up or down, the overall alignment is generally a sign something very rare and serious is about to go down. Among the more disturbing numbers coming out of the models are Portland cracking 110 degrees Fahrenheit (43 degrees Celsius), a threshold the city has never breached.
But models are only one tool in weather forecasters’ toolbox. Knowledge of local weather patterns and other influences not captured in models can help fine-tune the forecast. Even with those tweaks, though, the National Weather Service is still forecasting a slew of records to fall, including Portland’s all-time record of 107 degrees Fahrenheit (42 degrees Celsius). The Portland office is calling for “oppressive heat.” Meanwhile, the Seattle office is already tweeting graphics of the current heat records that are likely to fall in the coming days, which you can use as some kind of depressing extreme heat bingo card.
On Thursday, excessive heat warnings went up across the region with the National Weather Service warning of a “Dangerous and long duration” heat event. Among the recommendations the agency put out are staying out of the sun, checking on relatives and neighbors, and that kids and pets shouldn’t be left alone in cars for any period of time.
Because weather doesn’t just stop at the border, the record run of heat will continue in British Columbia. There, forecasters are already anticipating that the warmest-ever June temperature for the entire province of British Columbia will likely fall.
Overnight temperatures will also remain elevated throughout the region, and all-time hot low temperatures could also be toppled as well. That’s particularly worrisome since nighttime usually offers a reprieve. In a region where air conditioning isn’t as widespread as, say, Southern California, the relentlessness of the heat coupled with a lack of cooling options could unleash a wave of heat-related illnesses.
In an ironic twist, one factor that could lead to records not being broken is smoke from wildfires sparked due to hot conditions currently racking the West dimming the sun. Fires are already burning across the region and a large portion of the West is under a red flag warning as thunderstorms buzz through along with winds of up to 60 mph (97 kph). Humidity is expected to drop as low as 12% on the Arizona-Utah border as well, creating prime conditions for fires to ignite and spread. The National Interagency Fire Center is already at its second-highest preparedness level, which is triggered when there are “three or more geographic areas experiencing large, complex wildfires.” I’m not sure I’d call that a meteorological win, though, since smoke can be just as dangerous to public (and planetary) health as heat.
The heat wave is a symptom of the climate crisis, which is making extremes like this more common and more intense. It also shows how the climate crisis creates compounding problems. The West is in the midst of a disastrous megadrought that relentless heat has played a role in driving. Among other things, the drought has caused Lake Mead to drop to a record low, led farmers to tear out water-intensive crops, and curtailed development in at least one town. The Drought Monitor’s Thursday update shows more than 90% of the West has entered drought. It’s the first time in 21 years of Drought Monitor data that the West has crossed the 90% threshold, marking yet another ominous new milestone. (It made it to a shade over 89% in 2003.)
“We have human-caused climate change, making a moderate drought turn into a super megadrought,” Stewart Cohen, a retired climatologist after 35 years with Environment and Climate Change Canada, told the CBC. “We have a warmer climate because of greenhouse gases. It’s making droughts worse, dryer, and it’s making heat waves also worse.”
This is only the beginning, though. Climate change is expected to keep increasing the odds of heat and megadrought this century. The records that could fall this weekend and early next week will surely not be the last. But if what we’re seeing out West is any indication, we have a lot of work to do to ensure water systems, cities, and forests are ready for what comes next.
Update, 6/24/21, 9:57 a.m.: This post has been updated with more details as more heat watches and warnings go up and wildfires spread as well as a new update on drought conditions. Stay safe out there.