Arctic air will sweep across the Midwest and East Coast, which may leave you wondering if it's going to be a long, cold winter. Here's the reason it won't last long.
Another round of frigid air is heading to the Midwest and East Coast this week, triggering more snow, dangerous travel conditions and icy wind chills across 30 states from North Dakota to Georgia. It may even leave residents wondering: Is this a sign of what's to come the rest of winter?
The short answer is, probably not. This winter was forecast to be marked by La Niña -- a global climate pattern in which cool waters well up to the surface from deep in the eastern Pacific Ocean. While the pattern has yet to officially emerge, its influence typically means the season won't experience wall-to-wall snowy and cold winters in the East.
But it won't make the incoming surge of cold air feel any less cold. In addition to biting cold, widespread light-to-moderate snow is expected across the Midwest and Northeast, creating localized whiteout conditions.
The latest polar plunge will also kick-start the lake-effect snow machine once again, though accumulations won't be as prolific as they were during the most recent event.
The longer answer on whether the cold is here to stay involves a meteorological concept known as persistence, which is influenced by the memory of the ocean.
It refers to the tendency for weather patterns to become stuck on repeat for weeks or months, like the fall drought across the United States or the season's weirdly warm weather.
This persistence factor will help pull the central and eastern states out of the depths of the chilly -- soon. But first, another cold snap.
What to know about the latest Arctic blast
The latest Arctic blast will enter the Upper Midwest on Wednesday before surging toward the East Coast on Thursday.
It will linger in the eastern states on Friday and Saturday, then push offshore.
Compared to last week's polar plunge, this round of icy air will be coupled with even stronger winds, leading to frigid wind chills.
On Wednesday, strong wind gusts in excess of 40 mph are forecast to hit at least 10 states from North Dakota to Ohio. Sub-zero wind chills are possible from the Dakotas to Wisconsin.
On Thursday, similarly blustery conditions are expected across the Great Lakes, Northeast, Mid-Atlantic and even parts of the Southeast, leading to wind chills in the single digits, teens and 20s -- stretching as far south as northern Mississippi, Alabama and Georgia.
As of early Wednesday, the National Weather Service had issued wind advisories for eight states in the Midwest and 12 states along the East Coast. A smattering of advisories, watches and warnings for snow stretched from North Dakota to Maine, with freeze warnings for southern Alabama, Georgia and northern Florida.
When combined with snow, the winds will reduce visibility, cause brief whiteout conditions, blow around loose objects and may cause sporadic power outages.
Ohio, West Virginia, far western Maryland and parts of Pennsylvania and New York will awaken to a fresh blanket of snow on Thursday, leading to slippery conditions.
Flakes will fly in New England away from the coast, leading to moderate accumulations in the mountains of western Massachusetts, Vermont, New Hampshire and Maine.
The cold air will contrast with the record warm waters of the Great Lakes to produce yet more lake-effect snow from Wednesday night into the weekend.
The heaviest totals, exceeding a foot in the most persistent bands, are forecast to fall east of Lakes Huron, Erie and Ontario, with treacherous driving conditions likely from Thursday through Saturday.
When will the milder weather return?
A vastly different weather pattern will begin to take shape late this weekend, as mild, Pacific air spreads into the central states and reaches the East Coast on Monday.
Instead of teens, 20s and 30s, temperatures will rise into the 40s, 50s, 60s and even 70s for some.
While that pattern looks set to return next week, it doesn't mean it will suddenly be 70 degrees and sunny once again.
An initial round of warmer-than-average conditions from late in the weekend into early next week will give way to briefly cooler weather in the mid-to-late-week period.
Then, a more persistent spell of mild weather may settle in from the weekend of Dec. 14.
Here's why it won't last
The new pattern is reminiscent of the one that brought persistently warm and dry conditions throughout fall.
What contributes to this persistence factor is something known as ocean memory -- like a giant chalkboard where past conditions leave faint marks, allowing patterns to linger and influence future behavior.
Because oceans store and release heat more slowly than the atmosphere, their temperature doesn't change nearly as rapidly or fluctuate as much. As a result, atmospheric patterns like a persistent area of high or low pressure, or an anomaly in the jet stream, can linger for long periods.
During the fall, low pressure commonly sat near the Pacific Northwest, sandwiched by a high pressure system to the east, covering much of the United States, and another near Alaska's Aleutian Islands.
This drove weirdly warm conditions early in November and was a major factor in the record-breaking coverage of drought across the country.
As that pattern returns, signs are that colder-than-average temperatures will be the exception, not the rule, leading up to the holidays, due in part to the memory of the ocean.