A significant winter storm event is expected to take place over the Western U.S. on Wednesday and Thursday as a strong low pressure system along with an arctic air mass sags south from the Gulf of Alaska.
By Thursday afternoon, temperatures over east of the Rockies will drop as much as 50 degrees from seasonal averages. Heavier snow is expected to the western and northern sides of the mountains including the Cascades and Rockies. Otherwise, widespread snow showers are expected from the Pacific Northwest to northern Rockies Wednesday, reaching Northern Plains and Northern California on Thursday morning. Snow levels are expected to drop down to near sea level.
Farther east, a cold front is expected to push eastward through northern Plains and dump widespread snow showers from the Dakotas to western Great Lakes.
Meanwhile, high pressure is expected to build southward across eastern half of the nation Wednesday, providing cold and dry weather. To the south of the ridge, a cold front will become stationary along the central and western Gulf coast. Expect north winds to stream across the Mississippi Valley on Wednesday and support scattered showers and thunderstorms. By Thursday morning, another significant storm will develop in the Central U.S. as some energy originated from the Pacific meets up with the Gulf moisture.
Temperatures in the Lower 48 states Tuesday ranged from a morning low of -22 degrees at Saranac Lake, N.Y., to a high of 87 degrees at Melbourne, Fla.
Weather Underground: http://www.wunderground.com
National Weather Service: http://iwin.nws.noaa.gov