The Pacific "Blob" is back! The "Blob" we are referring to is a large area of warmer water that stretches over the North Pacific Ocean.

This blob of warmer water has the ability to cause major disruptions to weather and to marine life.

What Causes The Blob?

When most of you hear about The Blob, you probably think of famous movies from the 1950s or 1980s about alien monsters.

But as a meteorologist, my brain turns toward the Pacific Ocean — plus I wasn't born when those movies came out.

The culprit behind the blob is a stubborn area of high pressure that stalls over the ocean.

High pressure systems are often associated with stable, calm air. And that is true for this high as well.

This high's calm air causes winds in the region to decrease. These winds are needed for a process called upwelling. Upwelling, when colder, nutrient rich waters rise from the depths, is essential for marine life. This process allows the colder air to mix with the warmer air on the surface, which keeps the temperatures down and animals comfortable.

Warm water not being able to mix with cooler water for animals is the equivalent to our air conditioning being out in the middle of August.

Another way to think of this is to think of heat domes, high pressure systems that bring days of hot weather to parts of the U.S. The high pressure over the Pacific Ocean is doing a similar thing.

Blob’s Impacts on Nature

If you are wondering what the blob’s specific impacts were, I have you covered.

With the blob’s ocean temperatures warming, water is less efficient at mixing and ocean currents slow.

This means that nutrients are unable to spread as easily and there is less oxygen for marine life, which is obviously extremely important for parts of the oceanic food chain.

The news isn’t all bad: Some species actually benefit from this. Take sardines and tuna, for example.

But, salmon and cold-water plankton are unable to handle these temperatures, which greatly impacts what these animals eat and what eats these animals.

The 2015-2016 Common Murre die-off was the largest on record due to these birds not being able to eat enough cold-water forage fish. Marine mammals like whales and sea lions were exposed to toxic algae and saw food shortages as well. California fishers also saw fewer crab and more whale entanglements as whales were desperate for food.

The blob of 2019 also caused migration patterns of animals to shift, leading to more warm water species of marine life shifting farther north. This led to native animals in certain locations being threatened.

(MORE: Weather Words: The Blob)

Weather Impacts As Well

As if the marine life impacts of these Pacific Blobs aren't bad enough, weather across the U.S. also gets impacted.

The warmer Pacific Ocean will lead to more moisture for storms impacting the West Coast.

But, it can also result in warmer temperatures along the West Coast.

Plus, any tropical system that can take advantage of this warm and moist air mass will have better chances of staying alive longer.

And with a "Strong" to "Super" El Niño on the way, it is more likely we will see an active Pacific Tropical Season.

(MORE: Pacific Tropical Season)

When a blob like this is in place, it can lead to a shift in the jet stream, which can lead to a dislodging of the polar vortex and potentially result in colder and wetter weather for parts of the East.

We are already seeing that with the updated to the May temperature outlook, where they called for a weakening in the polar vortex leading to below average temperatures for the East.

(MORE: May Temperature Outlook)

The Blob’s Backstory

For the lore nerds, let's give the backstory of this blob.

First observed in 2013, a stubborn area of high pressure led ocean temperatures to increase to 7 degrees above normal.

For the record, that is a huge jump for oceans, where it takes a lot of persistent heat to make temperatures increase.

In its prime, this Pacific blob stretched more than 1,000 miles wide and 300 feet deep before eventually splitting into three smaller blobs.

The next blob occurred in 2019 and brought record temperatures to the Northern Pacific.

As our planet warms, the concern is that these Pacific blobs will become more frequent.

And in fact, they are.

According to a study in Nature, between 1925-1954 and 1987-2016, there was a 54% increase in annual marine heat wave days globally.

More studies have come out recently to add to the fact that maritime heat waves are increasing.

Rob Shackelford is a meteorologist and climate scientist at weather.com. He received his undergraduate and master’s degrees from the University of Georgia studying meteorology and experimenting with alternative hurricane forecasting tools.