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‘Blob Jr.’ might not last, but the marine heat wave has made for hotter nights

Despite a summer that has been relatively cool overall, a warm area of surface water has formed off the West Coast. It’s about 3-5 degrees warmer than normal for the eastern Pacific Ocean and covers about 6.5 million square kilometers, from Alaska to Hawaii to California. It has put federal fisheries and marine scientists on alert.

The National Oceanic and Atmospheric Administration announced Thursday that the area formed in mid-June this year, offshore of the Gulf of Alaska.

It’s reminiscent of the so-called "Blob" that persisted from 2014 into 2015 and had devastating impacts on juvenile salmon and other marine life. This new marine heat wave could still go away, the scientists stressed. But NOAA Fisheries is concerned enough to announce its arrival. They named it the Northeast Pacific Marine Heatwave of 2019.

Credit Courtesy of NOAA Fisheries.
Courtesy of NOAA Fisheries.
Sea surface temperature anomaly maps show temperatures above normal in orange and red.

KNKX weather expert Cliff Mass is calling it “Blob Jr.” He says it’s relatively young compared to its scary predecessor and not a very stable system yet.


“I wouldn’t be too worried yet,” Mass said. “First, it’s very shallow — which means it’s very vulnerable to be destroyed.”

That’s because the main cause of the tenacious warmth of the sea surface temperatures is the lack of upwelling and mixing of colder water from the depths. This is due to unusually persistent high pressure this summer and resulting light winds over the eastern Pacific.

But Mass says this could all fall apart soon, as typical autumn weather starts to set in. The current warm patch extends only about 50 meters deep, compared to 200-500 meters with the Blob.

“We haven’t gotten to the big storms of the fall and the winter," Mass said. "And the current forecasts indicate much more storminess developing over the Pacific Ocean. So I suspect that the Blob is at its maximum extent and magnitude right now.

“And as the winds pick up, as storminess returns to the Pacific, I suspect the Blob will weaken substantially during the next month or two.”


Mass says even though he’s not too worried yet, he has been fascinated by the formation. After poring over all kinds of local data, he discovered a correlation. He says the warmer sea surface temperatures coincide with equally warmer nighttime lows in Western Washington and Oregon.

“The minimum temperatures — have you noticed that the temperatures haven’t gotten as cook at night as usual?” Mass said. “We have been about five degrees above normal — it hasn’t cooled as much at night.”  

Mass says he is convinced the reason for that is the warner surface of the Pacific — which is as much as 5 degrees above normal. He looked to Eastern Washington to check his hypothesis — and found that the minimum temperatures were normal there, where the land is shielded by the Cascade Mountains from the effects of the ocean.

“And in fact they haven’t had the effect, they’ve gotten cooler at night,” Mass said. “So, this warm ocean is affecting us substantially here in Western Washington — but we notice it on the minimum temperatures, not so much on the maximum temperatures.”


Mass says that, with the devastation of Hurricane Dorian in the news, many people are hearing about the effects of warmer ocean water giving more power to tropical storms. And with the marine heat wave now in the news, he has been asked if the Pacific Northwest needs to worry about hurricanes happening here.

“The answer is no,” Mass said. “To have a hurricane, you need a minimum of around 80 degrees Fahrenheit for the sea surface temperature.”

He says that will never happen here, where even with the unusually warm conditions right now, the temperature off shore is only about 60 degrees.

“We’re not even in the neighborhood — even if our temperatures warmed up 10 degrees, it wouldn’t be warm enough for hurricanes,” Mass said. “That’s one problem we will never have to face.”  


Mass says Friday might feel like the last day of summer. Temperatures will reach 80 degrees with partly cloudy skies and a few showers in the Cascade Mountains and Eastern Washington.

“It should be dry in most of Western Washington and quite warm,” he said. “So, enjoy the warmth — this is it!”

Mass says over the weekend everything starts to shift, as an upper level trough moves in.

Saturday will be cooler, but no rain yet, with partly cloudy skies and temperatures in the 70s. “A pretty decent day,” Mass said.

Sunday more showers will come in, especially in the Cascades, but Mass predicts scattered showers all around Western Washington, with temperatures sliding down to around 70.

Monday-Tuesday we stay in the cloudy and showery pattern, which will continue for several days, Mass says.

Editor’s note: You can meet Cliff Mass and Bellamy Pailthorp and the rest of the radio station’s staff at the KNKX block party on Saturday, where the station will be celebrating the opening of its new Tacoma studios. Mass says the weather should be perfect for the event.

Weather with Cliff Mass airs at 9:02 a.m. Friday, right after BirdNote, and twice on Friday afternoons during All Things Considered. The feature is hosted by KNKX environment reporter Bellamy Pailthorp. Cliff Mass is a University of Washington professor of atmospheric sciences, a renowned Seattle weather prognosticator, anda popular weather blogger. You can also subscribe to podcasts of Weather with Cliff Mass shows, viaiTunes or Google Play.

Bellamy Pailthorp covers the environment for KNKX with an emphasis on climate justice, human health and food sovereignty. She enjoys reporting about how we will power our future while maintaining healthy cultures and livable cities. Story tips can be sent to