As a brutal surge of cold air invades much of the East over the coming days, a much different weather pattern will be found across the West.
A persistent area of high pressure centered over the Great Basin will continue to be responsible for promoting more dry weather. In fact, this center of high pressure has been the strongest so far this winter.
Although the majority of the West will be enjoying warm and sunny weather into next week, not everyone will be experiencing mild air and copious amounts of sunshine.
Areas of low clouds, fog and stagnant air will continue to be found throughout many of the interior valleys of the Northwest into early next week. Freezing fog will also be possible in locations that have below-freezing temperatures.
A strong push of warm air aloft in combination with weak winds in the valleys due to high pressure has been responsible for creating a meteorological phenomena known as a temperature inversion.
Typically in the lower atmosphere, the air near the surface of the earth is warmer than the air above it, largely because the atmosphere is heated from the ground up.
A temperature inversion, like the one occurring over the West now, refers to an increase in temperature with height. The warmer air aloft acts as a lid and holds the cold and stagnant air in the lower levels of the atmosphere.
As is the case with the Northwest, mountains can increase the strength of the inversions in the valleys.
The light winds in the lowlands will create very little to no movement of the air throughout the region, resulting in deteriorating air quality, below-normal temperatures, and areas of persistent low clouds and fog.
As pollutants from vehicles, wood burning and industrial factories continue to be emitted into the air, the inversion will continue to trap these pollutants near the ground, leading to poor air quality.
Residents with respiratory problems, young children and the elderly in many of the valley locations from western Washington and Oregon into northern Idaho should limit the amount of time they spend outdoors through early next week.
Locations above the inversion in the higher terrain will experience plenty of sunshine and mild temperatures into early next week.
On Wednesday, the strong ridge of high pressure will begin to break down as an upper-air area of low pressure moves into the Pacific Northwest. This system will break down the inversion leading to improved weather conditions in the lowlands.
A multi-vehicle accident involving 20 to 30 vehicles occurred amid snow showers and brutal cold, led to the shutdown of Interstate 78 in Lebanon County, Pennsylvania, Saturday morning.
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 Valentine's Day weekend.
The dangerous cold gripping the eastern United States will set the stage for disruptive snow and ice to unfold from Tennessee and Georgia to Maine Presidents Day into Tuesday.
Voters heading out to the polls on Saturday, Feb. 20, can expect mild weather and dry conditions for the next step in the 2016 Presidential Election.
Heavy rain will raise the risk of flooding across more than a dozen states in the Southeast on Presidents Day to the East Coast on Tuesday.
Umbrellas will be needed on Valentine's Day as scattered showers overspread Germany.
Eastern US (1985)
Great Ohio Valley snowstorm whips snow into mountainous drifts and strands hundreds. In southwest Ohio 10 plows were stuck in the drifting snow and abandoned. Over a foot of snow in central and eastern Kentucky with 10 - 15 ft. drifts. Over 2 inches of snow in most of North Carolina.
Minneapolis, MN (1990)
String of 48 consecutive days with above normal temperatures broken.
Fairbanks, AK (1999)
-36 degrees; a record 19 straight days with lows less than -35 degrees.