An intense weather pattern including two areas of low pressure, one over the High Plains and one over the Southern Plains, will converge over the Central U.S. on Tuesday. The systems will strengthen together as they move off the higher elevations and into the Plains, but moist flow from the Gulf of Mexico will help this system produce significant snow and rain over the Eastern half of the nation. Expect two strong fronts to be produced with a warm front extending up the Ohio River Valley and into the Northeast, while a cold front extends southward over the Southeast and Gulf states. Starting with the Upper Mississippi River Valley, expect light snow in the morning, with blowing snow throughout the day as winds range from 10 to 20 mph. In the Mid-Mississippi River Valley, severe winter storm advisories have been issued due to snowfall accumulation of 5 to 8 inches likely across Missouri and Illinois. Blizzard conditions are also likely as winds reach up to 25 and 30 mph, gusting up to 40 mph. As this system moves up the Ohio River Valley in the afternoon and evening hours, expect increasing snow showers throughout the day, with up to 12 inches anticipated Tuesday night. New England and the Northeast will also see increasingly snowy conditions. Expect a messy combination of snow and sleet across Pennsylvania and New York state with accumulation up to 6 inches.
Temperatures in the Lower 48 states Monday have ranged from a morning low of -31 degrees at Havre, Mont., to a high of 86 degrees at Laredo, Texas.