Blob The Third

In my AP European History class back in high school, I remember being astounded by some of the suffixes that the kings and queens had. With a name like Louis XVI, is it any surprise that the French rose up and demanded a change in government? In the spirit of European monarchies, we have our own budding dynasty here in the Northeast Pacific: the Blob. And just a year after Blob II relinquished the throne for the 2019-2020 winter, Blob III has picked up right where Blob II left off.

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.

But the Blobs are hardly a beloved monarchy. In fact, most Pacific Northwesterners – myself included – despise the Blob. 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.

The Blob dissipated during the 2015-2016 winter with the development of a strong El Nino and a deep, persistent area of low pressure in the Northeast Pacific that helped mix the water column and bring cooler, more nutrient-rich water to the surface. Since then, we’ve seen two other, shallower warm “Blobs” off our coast. Because these Blobs have been shallower (approximately 30 meters deep as opposed to 100 meters during the 2014-2015 Blob), they can mix out easier and tend to be more fleeting, and they haven’t had the same disastrous impacts on the ecosystem because the water below 90-100 feet is still nutrient-rich.

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 during this autumn 2020, yet another Blob has developed off our coast, once again giving us well-above-average low temperatures.

Blob 101

Our 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 sensible 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. Additionally, the contributions may vary based on the season; for example, sensible warming may play more dung the cold season, while added moisture content play play more of a role for overnight lows during the warm season.

Current Blob Status

The current Blob extends all the way from Haida Gwaii south to Baja California and extends well over 1,000 miles offshore. Sea-surface temperatures off the Washington and Oregon coasts are currently as much as 3-4 degrees C (5-7 degrees F) above-average.

This had had a huge warming influence on our temperatures, particularly our overnight lows. Since 9/1, only 5 days have had below-average overnight lows, and three of those (9/11, 12, and 13) were solely due to the extremely thick smoke over the area.

Blob Forecast

It’s hard to know exactly when this Blob will dissipate. The summer 2019 Blob lasted only a few months, but the 2014-2016 Blob lasted 1.5-2 years. A lot of it depends on the amount of ridging we experience this winter along the West Coast. 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 giving us a much better outlook for mountain snow this winter. The shallow depth of the Blob means that it could mix out fairly quickly in spots, but the sheer size means that it the Blob may not dissipate completely until 2021.

NOAA released an updated winter forecast last Thursday, 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. Given how warm and expansive the Blob is, I think their 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.

In the much shorter term, I’m watching the potential for some early-season winter weather next week. Uncertainty is still very high and not all models are on board, but there’s the potential for a few favored spots in the lowlands to see some highly unusual October snowflakes next weekend. I’ll have another blog shortly on this upcoming event, and follow my Facebook and Twitter pages for more frequent updates.

Have a great week!
Charlie