The all-powerful "Blob" of the Northwest Pacific is back — and it's come to wreak havoc on winter weather forecasts across the United States.

What is this mysterious threat and why does it have such a fantastic name?

The Blob is a large mass of relatively warm water that forms in the Pacific Ocean off the coast of North America. First detected in 2013, it appears as a very pronounced blob of red, orange or yellow on sea surface temperature maps.

The Blog as captured in 2014 by NOAA. The Blob as captured in 2014 by NOAA. (Photo: NOAA)

The culprit for its formation this year is likely an area of high pressure that has persisted over the Gulf of Alaska. This has not only kept the region unusually warm, but also delayed the typical snowy weather that comes in the fall. In Fairbanks, they've yet to see any snow –– the latest on record.

"Persistent high pressure is associated with lighter winds. Such light winds result in less mixing in the upper layer of the ocean, so less cooler water from below is mixed to the surface," University of Washington atmospheric sciences professor Cliff Mass wrote on his weather blog. "The result? A warm water anomaly and the rebirth of the BLOB."

Will it stay or will it go?

When the Blob tends to stick around, as it did during the winters of 2013-2014 and 2014-2015, it forces the jet stream to the north — bringing unusually dry and warm conditions to the West and, as the jet stream crashes back down, extremely cold and stormy conditions to the East. Whether or not this current iteration haunting the West Coast will stick around (its 2015 variant hung on for a full year) is up for debate, but Mass sees some hope.

"How long will BLOB Jr. last? At least as long as we have persistent high pressure over the North Pacific," he writes. "As this point, it looks like things are evolving to a pattern with less high pressure offshore, so the BLOB should weaken." With a nod towards past horror films, he adds ominously: "Unless is doesn't!"

So maybe don't hide the children, but it might be a good time to make sure they're bundled up for some rough winter weather. The Blob is BACK — AND THIS TIME ... well, we'll see.

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Return of the great Pacific 'Blob' may intensify winter storms in U.S.
The large mass of warm water called "The Blob" in the Northeast Pacific may help form unusual weather patterns across the U.S.