A large, lumbering storm system in the West will be the weather focus for much of the week.
The week will start off with a Pacific storm raging across California. Heavy rain will fall from the Bay Area to San Diego, with heavy snowfall across the Sierra Nevada. By Tuesday evening and Wednesday, that precipitation will move into the Great Basin, with largely heavy, wet snow in the plateaus and rain in the valleys.
High pressure will control the vast majority of the rest of the country on Tuesday and Wednesday, with sunshine expected from the Rockies to the Eastern Seaboard. The exception will be along the Southeast coast, where a developing low pressure system will produce clouds and breezy conditions.
The broad area of high pressure will lead to oodles of mild temperatures in the eastern two-thirds of the U.S. Highs in the 30s and 40s will be found in the Northeast, but 50s, 60s and even a few 70s will flood the Plains, Ohio and Tennessee valleys and the remainder of the East. Locations such as the Twin Cities could be as much as 20 to 25 degrees above average this week! Meanwhile, cooler 50s and 60s can be found across the valleys of the West, with 20s and 30s in the mountains.
The midweek storm will start to spread out as the weekend approaches. Even as another rainmaker moves onshore in the West, rain and high-elevation snow will make their way across the Rockies and into the Plains. The good news is that as time goes on, the intensity of the storm and the flood risk will progressively lessen.
Meanwhile, the East Coast and the Deep South will remain under the influence of high pressure, leading to continued sunny weather for Thursday, although Friday may see a few showers finally cut into the pattern from the Great Lakes to the Mississippi Valley.
Temperatures will remain on the mild side ahead of the big storm, with plenty of 30s, 40s and 50s from Wisconsin to Maine and Kansas to Delaware. Expect to see 60s, 70s, and perhaps a few 80s across the Southern Tier. The West will remain the cooler spot, with 20s in the highest elevations, widespread 30s and 40s, and 50s in the valleys. Only extreme southern California and Arizona will crack 60 degrees.
The stormy pattern will take a bit of a breather as we arrive at the weekend. Low pressure will move across southern Canada, but without access to much moisture, will have limited opportunity for rain and snow development. A pair of weak disturbances will make their way across the southern Rockies and Deep South, with mountain snow in Colorado and otherwise pockets of heavy rain.
The primary weather features will be “big blue H”s, which will dominate the West Coast, the northern Plains and the East Coast for the early part of the weekend, congealing into one dominant western high pressure system by Monday. While the East Coast will start off dry, rain and snow will eventually be in place across the Northeast to round out the weekend. On the flip side, the West Coast will enjoy a quiet weekend.
“Nice” will be a relative term this weekend with regard to temperatures. While 50s and 60s will continue to dominate the East, with 40s limited to New England, a push of colder air will start to build southward into the West where high pressure in dominant. Expect to see highs in the 20s from the Rockies to the Upper Mississippi Valley, with 30s, 40s, and a few 50s spreading across the Plains and Mississippi Valley. Fifties and 60s will be common along the West Coast and across the lower Mississippi Valley.
