A wintry cold blast that has already triggered snow in a wide area of Europe will spark outbreaks of heavy snow in the west by midweek.
Much of France will be subject to snow, as will areas as far-flung of northern Spain and eastern Great Britain, between Tuesday and Thursday. Up to 6 inches of snow will blanket Paris by Thursday, for instance.
Locally, snow will fall heavily, bringing disruption to air and ground traffic.
Recent days have had up to a foot of new snow from eastern Scotland to northeastern England, owing mostly to an abnormally cold, damp wind flow off the North Sea.
On Monday, new snowfall of 10 inches mantled Poprad, Slovakia, as a wintry storm tracked across central Europe into eastern Europe.
The coldest air of the winter will plunge southward across much of the eastern United States and will feature single-digit and sub-zero temperatures in the Northeast during the Valentine's Day weekend.
A storm unleashing snow from the mid-Atlantic to the Northeast on Tuesday will slow travel and cause delays.
Episodes of snow and slippery travel will affect the mid-Atlantic states and parts of New England through Thursday.
Denver Broncos fans celebrating the Super Bowl win will see ideal conditions for Tuesday's parade and pep rally.
A new study has found that nearly a tenth of cereal crops have been wiped out due to droughts and heat waves between 1964 and 2007.
Chilly air will visit New Orleans this year for the annual Mardi Gras celebrations and linger over the city until later in the week.
New York City, NY (1934)
Absolute minimum -15 degrees.
Philadelphia, PA (1934)
Absolute minimum: -11 degrees.
Vanderbilt, MI (1934)
-51 degrees; record low for state.