The Blob Reaches Our Shores
The “Blob” first entered the Pacific Northwest meteorological lexicon way back in 2014, when UW atmospheric sciences professor and Washington State Climatologist Nick Bond affectionately dubbed the amoebic mass of warm, sterile ocean water in the Northeast Pacific as such. Such oceanic “warm spells” had surely occurred throughout the climate record, but the 2014-2015 event was so anomalous that it needed its own scientific term. And in the spirit of hard-hitting meteorological classics such as “polar vortex and bomb cyclone,” the Blob was born.
Current sea-surface-temperature (SST) anomalies showing the “Blob” of warm water in the NE Pacific. Above-average SSTs span all the way from Haida Gwaii south to Baja California, and extend well over 1,000 miles offshore. SSTs are as much as 3-4 degrees C (5-7 degrees F) above-average off the WA/OR coasts.
Credit: NOAA/California Current IEA
But the Blob is hardly a beloved Pacific Northwest fixture. During late 2014, the Blob – which had been stationed several hundred miles off the West Coast – began to creep eastward towards our shores. The warm, sterile water associated with the Blob had devastating impacts for marine life. During late 2014, there was a massive die off Cassin’s auklets along the Washington/Oregon Coast, which feed on zooplankton and krill and were starved when the warm, nutrient-poor Blob moved into their feeding grounds. In 2015, other organisms throughout the food chain, from sea lions in California to fin whales in the Gulf of Alaska, saw increased mortality rates, and many Puget Sound salmon runs are still recovering from the effects of the 2014-2015 Blob.
The Blob isn’t just devastating for marine life. It’s devastating for Pacific NW snow lovers as well. The 2014-2015 ski season lasted a measly three weeks for Alpental just north of Snoqualmie Pass, and it’s not like those weeks featured knee-deep pillows of powder!
Since the 2014-2015 “mega-blob,” we’ve seen two other, shallower warm “Blobs” off our coast – one in the summer of 2019 and another that has developed this autumn. However, these shallower blobs have had similarly warm surface temperatures compared to the 2014-2015 Blob, and they’ve had a similar warming effect on our temperatures. The summer 2019 Blob gave the Pacific Northwest some of its warmest summer overnight low temperatures on record due to higher dewpoints and less overnight cooling for the Pacific NW, and the current Blob has done the same this autumn.
These “Blobs” are formed when a ridge of high pressure moves over the Northeast Pacific. This ridging prevents storms from coming through and mixing the water column, allowing the upper-most levels of the ocean to become stratified between warm, sterile water at the surface and cool, nutrient-rich, acidic water below.
The Blob warms the Pacific Northwest in two primary ways. First, air moving over the Blob is warmed (or cooled less) simply by the warmer-than-average sea-surface-temperatures associated with the Blob. Second, this air picks up more water vapor as it moves over the relatively warm Blob. Water vapor is a powerful greenhouse gas and helps prevent temperatures from falling significantly at night (this is why the tropics are so warm at night!).
This second effect – the added moisture content and stronger greenhouse effect – appears to have a more substantial impact on warming than the first effect – the heat transfer from the Blob to the atmosphere – but there is still research that needs to be done into how big of a contribution each of these variables play.
NOAA Winter Outlook: Too Cool?
NOAA released an updated winter forecast in mid-October, and with the burgeoning La Nina in the tropical Pacific, they are going with a typical La Nina temperature and precipitation distribution, with above-average precipitation and below-average temperatures over the northern tier of the US and warmer-than-average conditions for the southern 2/3rds of the country and East Coast. They appear to have NOT taken the Blob into account with these long-range forecasts.
La Nina tends to bring enhanced troughing to the Pacific NW, with cooler and wetter-than-average weather as a result. Such a pattern would help erode the Blob and give us a much better outlook for mountain snow this winter. The shallow depth of the Blob means that it could mix fairly quickly in spots, but the sheer size means that it the Blob may not dissipate completely until 2021.
Given how warm and expansive the Blob is, I think NOAA’s forecasts for the Pacific NW are a little too cool, and I wouldn’t be surprised if they bumped their seasonal temperature forecast up a bit during their next update if this Blob persists, even if our current La Nina continues to intensify. For skiers and salmon alike, let’s hope this Blob disappears sooner rather than later!
Charlie Phillips is a Madrona resident who received his B.S. in atmospheric sciences from the University of Washington. He works in Portland as a meteorologist. Check out his weather website at Charlie.weathertogether.net