Weather across America

(NATIONAL) Heavy snow over parts of the Sierra Nevada Mountains and Upper Great Lakes, moderate snow over parts of the Central Rockies, and temperatures 10 to 15 degrees below average over the Northern Plains.

A front extending from the Middle Mississippi Valley, Central Plain and Rockies, and Southwest will move eastward to off the Northeast/Mid-Atlantic Coast and then over the Southeast and off the Western Gulf Coast by Tuesday evening. A high pressure over West-Central Canada will usher cold air over parts of the Northern Plains, bringing temperatures of 10 to 15 degrees below average, while the high moves southeastward to the Ohio Valley by Tuesday evening.

Weak onshore flow will produce coastal rain and higher-elevation snow over parts of the Pacific Northwest through late Monday night. More robust onshore flow will produce rain and higher-elevation snow over parts of Northern and Central California. The snow will be heavy over the Sierra Nevada Mountains through Tuesday evening. Additional upper-level energy will move over the Central Rockies, developing light snow from Sunday evening into Monday morning. The energy will create moderate to heavy snow over the Central Rockies from Monday evening into Tuesday evening.

Meanwhile, upper-level energy over the Northeast will produce light rain over parts of the Lower Great Lakes through Sunday night and higher-elevation snow over the Northeast through Monday morning. Overnight Sunday, as the wave of low pressure and associated upper-level energy moves into the Upper Midwest, moderate snow will develop over parts of northeastern Minnesota, northern Wisconsin, and the Upper Peninsula of Michigan. Rain will grow over the Lower Peninsula of Michigan on Monday and extend into the Ohio Valley. 

By Monday afternoon, as the precipitation expands southward, showers and thunderstorms develop over parts of the Tennessee Valley and the Lower Mississippi Valley. By Tuesday, heavy lake-effect snow will develop over the western Upper Peninsula of Michigan and moderate to heavy lake-effect snow over the rest of the Upper Peninsula of Michigan. Also, rain will move into the Northeast and parts of the Mid-Atlantic, southwestward to the Central Gulf Coast. The rain will change over to snow over parts of Northern New England by Tuesday evening.