Afternoon satellite and radar imagery show the Pacific moisture plume responsible for heavy rain and winter weather over parts of the Pacific Northwest and the northern Rockies continues to flow onshore, albeit in a weakened state.
The forecast for a lowering excessive rainfall risk looking toward midweek remains on track, although isolated instances of flash flooding are possible today in western Oregon/southwest Washington where a Marginal Risk of excessive rainfall resides.
Although the flash flood threat is expected to end by tomorrow morning, unsettled weather should remain overhead through midweek as remnant low pressure offshore will continue to direct moisture toward the coast.
Meanwhile, a frontal boundary is forecast to slide slowly across the Pacific Northwest to reach northern California by Thursday morning, bringing another shot of rain and modest high elevation snow into the region.
East of the Rockies, yet another Arctic cold front will support snow and wintry precipitation chances over the Northern Plains beginning Wednesday, although generally limited impacts are anticipated for this event as of now.
The same front will further spread snows across the Great Lakes, Northeast, and New England Wednesday-Thursday, with limited to localized minor impacts from snow accumulations possible.
Ahead of the front, Spring-like temps are in store for much of the CONUS, as Daytime highs are forecast to climb 10-30 above normal across most places from the central and southern Plains to the Mid-Atlantic and Southeast today and Wednesday.
A few daily high temperature records could fall in the central Plains and Southwest by the end of the work week.
Eventually, the aforementioned Arctic air mass should surge south out of the Upper-Midwest by Thursday and temporarily end the warm weather for the northern half of the CONUS.
Strong southerly flow should arrive in time for the weekend, however, to usher in above average temperatures once again over the Plains, Southeast, and Midwest. ■
A clipper system will move quickly across the northern Plains into the Midwest Friday and the Northeast by Saturday, bringing a wintry mix of rain and snow showers ahead of a sweeping cold front.