A surface low deepened as it moved from the northern Plains Monday morning to north of Lake Superior this morning. An occluded front extends from the low to another surface low in the central Appalachians. Snow fell to the west of the low on the cold side of the storm, with around 1/2 foot in many areas (with locally higher amounts). To the east across the Great Lakes, temperatures were above freezing, and rain fell, which caused the snowpack to become warm and snow melt to ensue.
A disturbance which rotated around the trough behind the surface trough caused around a foot of snowfall (locally to 1 1/2 feet) in and around the Wasatch Mountains yesterday. Except for the lower-elevation parts of the windward side of the Cascades through the Sierra Nevada, the West's and Plains' snowpack is predominantly cold and stable. Scattered blowing snow sublimation occurred in the High Plains due to freshening winds from the deepening low.
The system which covers the Great Lakes and Appalachians will move gradually eastward during the next couple of days. Around 1/2 foot of snowfall is probable north of Lake Superior today. Across the Appalachians and East Coast, widespread heavy rainfall is expected. Today, 1 to 2 inches of rain is expected New York and the northern Appalachians. Tomorrow, the heavy rainfall will be concentrated in the Northeast, with 1 to 3 inches of rain likely in eastern New York to central Maine; on Wednesday, the rain will fall in Maine. On the cold side of the storm, a foot of lake-effect snowfall is expected south and east of the central and lower Great Lakes. Rapid snowmelt will likely ensue in the lower Great Lakes and Northeast due to strong southerly winds, high humidities, above-freezing temperatures, and rainfall.
A cold front along the Northwest Coast will move inland today and weaken. Mild onshore flow and a jet streak aloft will help to cause up to a foot of snowfall for the higher elevations of the northern West through Thursday; locally-higher amounts are possible at higher elevations.
weather.gov
