Weather across America

(NATIONAL) Heavy lake-effect snow downwind from the Lower Great Lakes, heavy snow from parts of the Central Rockies, snow from parts of the Lower Mississippi Valley to the Northeast, and temperatures 25 to 40 degrees below average from the Northern Rockies to the Plains and the Valleys.

Cold high pressure over the Plains and a wave of low pressure along a stationary front will produce heavy snow over parts of the Central Rockies on Sunday evening into Monday evening. In contrast, upper-level energy and cold air will produce heavy lake-effect snow downwind from the Lower Great Lakes. Moisture flowing northward over the Western/Central Gulf Coast will intersect cold air over parts of the Southern Plains, Lower Mississippi Valley, Tennessee Valley, and Central/Southern Appalachians, creating a broad band of rain/freezing rain.  

The cold air associated with the high pressure will produce dangerously cold wind chills. The temperatures will be 25 to 40 degrees below average from the Northern Rockies to the Plains, Middle Mississippi Valley, and Ohio Valley. In detail, sub-zero wind chills will affect much of the U.S. and reach into portions of the South. Wind chills below negative 30 degrees below zero from the Northern Rockies to northern Kansas and into Iowa. 

Values will drop as low as negatives 50 degrees below zero from Montana across the western Dakotas. These wind chills will pose a risk of frostbite on exposed skin and hypothermia. Have a cold survival kit if you must travel.  In addition, lake-effect snow persists through Tuesday downwind from the Great Lakes. The arrival of colder air will generate heavy snow downwind of the Great Lakes through midweek, with additional heavy accumulations possible, especially across portions of northern Michigan, western and northern Upstate New York.  

Moreover, hazardous cold weather will persist and re-develop over parts of the Midwest. Parts of the Midwest will again experience near-record, dangerously low temperatures and wind chills, with subfreezing temperatures possible in the Deep South by late in the week. Heavy snow and blowing snow will continue over the Central Rockies from Sunday evening into Monday evening. In addition, wintry precipitation will develop over the Mid-South by late Sunday. 

Areas of snow, sleet, and freezing rain will continue to develop and extend east from the Southern Plains, through the ArkLaTex, and into the Tennessee Valley overnight Sunday into Monday. Several inches of snow are likely from Arkansas through the Tennessee Valley into the Southern Appalachians. Accumulating ice is expected from portions of central and southern Texas through the Lower Mississippi Valley into parts of the Tennessee Valley and Southern Appalachians. 

Plan on dangerous road conditions. With arctic air in place, impacts from wintry weather may last several days, resulting in a prolonged period of hazardous travel across some areas. Meanwhile, the snow extends into the Central Appalachians and Mid-Atlantic on Monday and Tuesday. 

Areas of light snow are expected to extend into the Central Appalachians and Mid-Atlantic beginning early Monday before potentially heavier snow lifts across the region late Monday into early Tuesday. Also, on Tuesday, snow will develop over the Northeast. Elsewhere, showers and thunderstorms will develop over the Florida Peninsula from Monday into Tuesday.