Seattle is in the midst of a mind-boggling winter heat wave. The temperatures might not sound impressive: high 70s? Pleasantly warm, not sweltering — but for this Pacific Northwest city, it is unprecedented.
Seattle-Tacoma International Airport hit 76 degrees on Monday and an astonishing 79 on Tuesday. It was the city’s highest temperature between the months of November and March on record, which dates to 1894.
“And I’m forecasting 76 for Wednesday,” said Chris Burke, a meteorologist at the National Weather Service in Seattle.
Even overnight temperatures have been extremely warm, according to Burke. “Last night, we didn’t drop below 59. There were a number of places with lows that bottomed out near 60. Typically we would have highs in the mid-50s, with a low in the 40s,” Burke said.
The extreme heat is being caused by a ridge of high pressure parked over the Pacific Northwest into southern British Columbia. The crest of sinking air warms the air at the ground and acts like a force field steering weather systems to the north.
“With strong high pressure over the area, easterly winds developed,” Burke said. “That lead to down-sloping winds off the Cascade Range and resulting warming. So overnight, even places up on the hills stayed warm.”
Seattle’s high of 79 was “above average,” even based on July standards. The hottest “average” high of the year falls on July 31, peaking at 77.4 degrees. This means Tuesday’s high temperature is toasty no matter how you slice it.
“We also had a number of low 80s,” Burke said. “And while we can’t connect a single event to climate change, it’s fair to say we’re getting a lot more record highs than lows.” The summery steam comes just weeks after an unusually cold and snowy February. It was nearly seven degrees below normal, with eight days of snow and 2½-foot snowstorms.
“After a month like that, I’d say people are coping with this week’s heat pretty well,” joked Burke. “There are even a few piles of snow left around here.”
By the end of the week, he expects temperatures in the 50s and rain to overspread Seattle.
The heat has not been relegated to the Lower 48, however.
The coastal community of Tofino, on Vancouver Island, about 150 miles northwest of Seattle, registered a preliminary peak temperature of 24.4 degrees Celsius — or 76 degrees Fahrenheit. Current water temperatures there stand around 46 degrees.
That reading is five standard deviations above the mean for March 19 temperatures in Tofino, according to Tyler Hamilton, a meteorologist at the Weather Network, making this an event occurring once every 17,800 years.
The toasty air mass extends into the Last Frontier. Sitka, Alaska — southwest of Juneau — hit 67 degrees Tuesday, its record high for any day between Oct. 7 and April 16. Records there date to 1944. Alaska is bearing the brunt of climate change, distinguished as one of the most quickly warming spots in the world.
In the meantime, the weather will settle back to more seasonal norms in the not-too-distant future. The ridge responsible for this warmth will break down and shift east by Friday. A renewed shot of chillier air will sweep in from the northwest. Near to slightly below-normal temperatures will stick around for most of next week before a pattern change into April.