Weather across America

(NATIONAL) Unsettled weather expands across the western U.S. with strong winds, high-elevation snows, and coastal and lower-elevation rains, an expanding area of showers and thunderstorms across the central and eastern U.S., and above average temperatures for the South and the Northern Plains.

A vigorous upper-level trough currently hurling onshore into the West Coast will send a wave of inclement weather rapidly from west to east across the country through the next couple of days. The Pacific Northwest is first in line to feel the impacts from this weather system including coastal and lower elevation rains and high elevation snow following the onset of strong gusty winds Sunday.

In the meantime, a low pressure system over the central High Plains will be energized as the vigorous upper trough sweeps through the western U.S. Showers and thunderstorms developing over the central Plains ahead of the low pressure system will likely expand toward the east and northeast for the next few days as the system expands and intensifies. This system will also help the mountain snows and lower-elevation rains to linger a bit longer over the central Rockies and High Plains through Monday and into Monday night.  

On the warm side of the system, thunderstorms could become severe particularly by later on Monday across the Deep South as a warm front lifts northeastward across the region with an influx of warm and moist air from the Gulf of Mexico. By Tuesday morning, the center of the low pressure system is forecast to reach into the Ohio Valley with widespread rainfall from the lower Great Lakes down into the Ohio Valley, southern Appalachians and into the interior Southeast. Thunderstorms could again reach severe levels across the Mid-South and possibly down toward the central Gulf Coast as the dynamic cold front sweeps across the region from west to east.  

Farther north, colder air from Canada could bring some light wintry mix into the upper Midwest early on Tuesday. The same can be said for interior New England Sunday into Sunday night with the passage of an arctic front. The remainder of the East Coast will be mostly dry through Tuesday morning before the leading edge of the moisture from the Ohio Valley storm arrives. 

Temperatures will be generally seasonable for the East Coast, cool and bit below average for New England, but will remain mild over the northern Plains. In contrast, temperatures will be below average across much of the West with the passage of the upper trough. Highs along the coast will be closer to seasonable with mostly 50s and 60s, and 70s for southern California.