Weather across America

(NATIONAL) A moderate risk of excessive rainfall anticipated along coastal central California, heavy snow likely over Sierra Nevada and Mount Shasta in California, and a warming trend expected to expand across the Great Plains.

The new week will begin with a rather potent low pressure system getting ready to deliver the next round of heavy precipitation into the West Coast with focus mainly across California. The first batch of moderate to heavy rain is forecast to reach coastal northern California later Sunday. This will be followed by the arrival of the heaviest precipitation associated with the system on Monday. 

A couple of inches of rain can be expected to fall across the lower elevations of northern California while coastal central to southern California is expected to receive the heaviest rains totaling a few inches through the next couple of days. These rains are expected to raise of risk of flash flooding to moderate levels in the affected areas. Meanwhile, the Sierra Nevada and Mount Shasta will be impacted by an onslaught of heavy snow on Monday, with new snow likely totaling a few feet through the next couple of days. 

By Tuesday, both the intensity and coverage of the precipitation are expected to decrease as the system pushes farther inland and weakens. Nevertheless, much of California will likely receive light to moderate precipitation on Tuesday as southern California is expected to see steadier rainfall moving in. Meanwhile, elevation-dependent rain/snow associated with the weakened system will spread northeastward across the Great Basin and into the northern Rockies over the next couple of days.  

Across the Northeast, a clipper system sliding across southeastern Canada will only bring limited areas of lake-enhanced snowfall across the lower Great Lakes and interior northern New England through Sunday night before tapering off Monday morning. Over Florida, a low pressure system developing over the Gulf of Mexico along a stalled front will traverse the Florida Peninsula by this evening before moving out into the Atlantic on Monday. 

Generally, a couple of inches of rain, with locally higher amounts, can be expected with this system. Meanwhile, the Great Plains and a large portion of the eastern U.S. will remain dry through the next couple of days. A warming trend is expected to expand across the Great Plains through midweek where an upper ridge is forecast to build. Dry conditions will extend into portions of the Four Corners region as well.