An expansive area of north to northwesterly flow between a departing storm system off the Canadian Maritimes and an axis of high pressure anchored over the Great Plains will continue to direct a cool autumn air mass farther south toward the Gulf Coast and even Florida.
Article continues below
However, as this high pressure weakens and begins to shift eastward, a reservoir of warm air over much of the western U.S is expected to to slowly filter into the Great Plains.
The warming process will be slower to occur farther east as the massive expanse of cool autumn air over the eastern half of the country will be slow to break down.
Under this weather pattern, scattered showers will once again be found through tonight from interior New England to the lower Great Lakes, down across the Ohio Valley, and as farther south as the southern Appalachians.
The showers should hold off along the Eastern Seaboard, but partly to occasionally mostly cloudy conditions will prevail this evening before the high pressure system finally slides across the region later on Tuesday with a better chance of seeing breaks in the clouds.
While much of the interior western U.S. has been dry, moisture associated with a cold front ahead of an upper trough will bring windy and rainy conditions into the Pacific Northwest and down into northwestern California for the rest of today.
This latest round of rain is forecast to end later on Tuesday from Oregon southward with the Olympic Peninsula in Washington remaining rainy through Wednesday morning upon the arrival of a warm front well ahead of the next Pacific system.
Meanwhile, a piece of the lead upper trough will penetrate farther inland, bringing a round of rain and high elevation wet snow across Idaho and Montana into early Tuesday.
By Tuesday night into early Wednesday, an Alberta clipper is forecast to slide southeastward into the far northern Plains where a round of mostly light rain can be expected.
Strong winds including maximum gusts up to 70 mph are possible on Tuesday across parts of the northern High Plains.
This has prompted High Wind Warnings to be issued for parts of northern and central Montana.
Meanwhile, southerly flow developing ahead of the Alberta clipper and a lee trough near the foothills of the Rockies will allow warm air to filter into the High Plains on Tuesday, resulting in afternoon high temperatures well into the 80s by Tuesday afternoon as dry conditions continue.
Meanwhile, above normal temperatures will continue over the Desert Southwest where high temperatures could top the century mark for the next few days. ■