Weather across America

(NATIONAL) Increasing precipitation chances, including mountain snow, plus much cooler temperatures and gusty winds for the West, much above average, record-tying/breaking warmth for portions of the Plains and Midwest, and showers and thunderstorms for the Great Lakes.

A deepening upper-level trough and accompanying surface cold front continued southeastward across the Northwest Sunday, spreading increasing precipitation chances, cooler temperatures, and gusty winds throughout the West over the next couple of days. Showers and thunderstorms producing heavy rainfall in the Pacific Northwest will remain possible Sunday night into Monday before beginning to wane later Monday evening. 

Lower elevation/valley rain and higher elevation mountain snow will spread inland from the Northwest into the northern Rockies and Great Basin Monday and the central Rockies by early Tuesday. The lower elevation rains will mainly remain light to moderate, but some locally heavy snowfall will be possible for the higher elevation mountains, particularly from the eastern Great Basin into the central Rockies on Tuesday. Snowfall totals of 6-12" will be possible. Higher elevations of the Black Hills may also see some heavier snowfall totals of 4-8". 

A transition to some snow later Tuesday looks possible for areas of the High Plains along the Front Range of the Rockies, but timing and any potential accumulation remains uncertain at this time. Much cooler temperatures will also follow behind the cold front as it pushes eastward through the West. Highs on Monday will fall into the 50s for most of the Pacific Northwest, northern Great Basin, and northern Rockies, with highs only reaching into the 40s by Tuesday across the entire Great Basin and into the northern Rockies. Highs will also fall into the 70s across the Southwest by Tuesday after a hot Sunday that saw highs into the 90s for many locations. Gusty winds are expected as well, especially across southern California, the Southwest, and into the central/southern Rockies Monday, and the central/southern Plains Monday into Tuesday. The Storm Prediction center has noted an Elevated Risk of fire weather (level 1/3) across much of this region Monday.

Meanwhile, much above average, record warmth for late October is expected for the Plains and Midwest as a broad ridge of high pressure builds northward ahead of the deep upper-level system in the West. Forecast highs are in the 70s and 80s for the northern Plains and Midwest and 80s to low 90s for the central/southern Plains. Numerous, widespread record-tying/breaking high temperatures will be possible. However, these temperatures won't last for long for more northern locations as the cold front in the West quickly pushes out into the northern Plains Tuesday, with highs behind the front dropping into the 50s. 

While not quite as abnormal, temperatures will also warm after a cooler Sunday along the East Coast, including some possible freezing temperatures for portions of the Mid-Atlantic Sunday night. Highs Monday-Tuesday will rise into the 60s and 70s for the Mid-Atlantic and Carolinas and the 50s and 60s in New England. While much of the rest of the country will be dry outside of the West, storm chances will begin to increase for the Great Lakes as moisture increases with a warm front lifting northward through the region on Tuesday. Some showers and thunderstorms are also possible along and behind the cold front pushing through the northern Plains by later Tuesday afternoon/evening.