Assisted by a southward shift in the polar vortex, temperatures plummeted to their lowest levels in decades in some locations of the Northeast at the start of Valentine's Day.
The polar vortex is a storm that is typically centered near the North Pole and tends to keep the coldest air trapped in northern Canada. Occasionally, this storm weakens or shifts enough to allow frigid air to plummet southward into the United States.
The frigid weather follows one of the warmest starts to a winter on record.
Dozens of locations in the Northeast shattered record lows for the date on Sunday morning.
Many locations dipped to their lowest levels of the winter, while some locations plunged to lower levels than all of last winter.
A number of locations had their lowest temperature since the 1900s.
Following another plunge from Sunday night into early Monday, a dramatic rise in temperature is forecast as a storm approaches the region a dose of heavy snow, ice and rain, prior to the middle of the week.
On Tuesday, many locations of the Northeast will experience temperatures climbing 40 to 70 degrees higher, when compared to lows from Sunday morning, with the greatest surge of warmth along the Atlantic Seaboard.