Weather across America

(NATIONAL) Snow developing across the upper Midwest to the upper Great Lakes as severe weather and heavy rain threat emerge across the Mid-South, more wet weather expected for the Pacific Northwest before a drying trend sets in, and a fire weather threat across large portions of the Central to Southern Plains.

A fairly deep low pressure system will be the main weather maker for the eastern two-thirds of the country for the beginning of the week. This system is currently consolidating over the northern and central Plains with two separate centers of circulation as an upper-level trough moves off the Rockies into the High Plains. Enough cold air will be available to support moderate to locally heavy snow mainly north of the low center across the upper Midwest Sunday. The snow will become more widespread Sunday night across the upper Great Lakes region as the northern low becomes the main system.  

Upwards of 6 to 8 inches of new snow with locally high amounts can be expected across the upper Midwest to upper Great Lakes. Farther south, a second low pressure center along a southern front will help organize and trigger showers and thunderstorms Sunday morning from Missouri eastward into the Ohio Valley. A better chance of strong to severe thunderstorms will arrive by late Sunday afternoon into tonight across the Deep South as the cold front associated with the northern low catches up and merges with the southern front.  

The primary threats will be damaging thunderstorm wind gusts, large hail, along with possible tornadoes. The merged system will deliver a round of snow from upstate New York to interior New England on Monday while scattered showers and thunderstorms move through a large portion of the eastern U.S. before colder and drier air will be ushered into the entire region behind a cold front.  Meanwhile, moisture from a relatively active Pacific weather pattern will continue to send moderate to heavy rain into the state of Washington today and into Monday. By Monday night into Tuesday morning, the offshore fronts are forecast to weaken and lift more northward toward western Canada, leading to a drying trend for the Pacific Northwest.  

Much of the rest of the western U.S. will be dry with a warming trend continuing through the next couple of days under the influence of an upper-level ridge. The warm air will spread into much of the Plains on Monday with little precipitation despite the presence of a pair of fronts. Much of the Great Lakes and Northeast will remain cold due to the passage of the aforementioned low pressure system.  Some wet snow Sunday morning in Maine will move off to the east behind a front as some lake-effect snow across upstate New York should gradually taper off today with the arrival of a high pressure system.