Flooding and flash flooding across central California and Nevada should be easing late Friday afternoon and evening as precipitation intensity lessens as the related storm system moves into the Intermountain West and the atmospheric river shifts away from the area.
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However, Southern California should see elevated flood/flash flood issues persist Friday night into early Saturday as the atmospheric river slows down its forward progression and slowly weakens.
The excessive rainfall/rapid onset flooding risk is expected to elevate again for portions of central and northern California Saturday night into Sunday as a moderately strong atmospheric river and warm front move into the region.
Heavy wet snow will occur at higher elevations of the Sierra Nevada into Sunday, shifting from south to north with time associated with both moisture plumes.
The snow will lead to difficult travel and combined with an already deep snowpack, may lead to increasing impacts from the depth and weight of the snow.
For areas near the northern Great Basin and Northern Rockies, there is the potential for convective snow showers and snow squalls Friday evening/night, which could lead to whiteout conditions and slick roads.
As the initial storm moves out of the Intermountain West onto the Plains, it will split into two pieces.
Within its southern portion, an area of showers and severe thunderstorms will develop near a new area of low pressure over parts of the Southern Plains and Lower Mississippi Valley and organize into a progressive line.
The Storm Prediction Center has issued a Slight Risk of severe thunderstorms over parts of the Southern Plains and Lower Mississippi Valley from Saturday into Sunday morning.
The hazards associated with these thunderstorms are frequent lightning, severe thunderstorm wind gusts, hail, and a few tornadoes.
Despite the potential for a progressive squall line, soils are saturated across portions of the Mid-South, which lends itself to an elevated excessive rainfall risk.
Excessive rainfall concerns should become more isolated as the activity moves through the Southeast on Sunday.
Meanwhile, within its northern portion, the initial low pressure area emerging from the Northern Rockies and then moving through the Northern Plains into the Upper Midwest/Great Lakes will help spur a winter storm which will generate periods of heavy snow across portions of northeast Montana, North Dakota, and into Minnesota and Wisconsin starting Friday evening and continuing through this weekend.
When combined with strong, gusty winds, blizzard conditions are anticipated across portions of North Dakota.
Scattered power outages are possible.
Snow-covered roads and reduced visibility will make travel difficult across impacted areas.
A complex low pressure system will move eastward off the northern Mid-Atlantic Coast by Saturday morning and strengthen as it moves out of sea.
As the storm moves east, several inches of snow are expected across West Virginia and southern New York Friday night into Saturday, which could cause some travel impacts and disruptions. ■