A storm headed into Southern Oregon from the Pacific early Wednesday is expected to bring rain on top of snow, which could cause flooding in Northern California and has led to landslide warnings throughout the region.

An atmospheric river flowing in from Hawaii largely will sidestep the Rogue Valley, which could get up to an inch of rain by Friday. A regionwide flood watch was issued through Thursday afternoon, according to the National Weather Service.

The warm storm will shoot the snow level up to as high as 8,500 feet in the South Cascades and portions of Northern California. Forecasts call for Pitt River to jump its banks near Canby Thursday, and minor flooding is possible on the Klamath and Scott rivers.

"Some of that snow will melt, and that's what's causing some of our problems," Weather Service meteorologist Brad Schaaf said.

The Coast Range will take the brunt of the storm's force, swelling the Chetco and Winchuck rivers close to flood stage, but those rivers were forecast Tuesday to stay below flood level, according to the Weather Service.

Localized flooding is expected throughout Curry County and western Josephine County, where the Illinois River near Kerby will hit about 17,000 cubic feet per second, according to NOAA's Northwest River Forecast Center.

The Rogue River was forecast to remain comfortably below flood stage through its upper and middle reaches, but it was forecast to nudge close to flood stage in Agness, which is 27 river miles from the ocean.

Oregon's Department of Geology and Mineral Industries is warning people to be alert for landslides and debris flows, especially in canyon bottoms, stream channels and at the bases of steep hillsides.

Bear Creek in downtown Medford was forecast to peak at about 6.5 feet, or flowing about 1,600 cfs, but well within its banks, the forecast center reported.

— Reach Mail Tribune reporter Mark Freeman at 541-776-4470 or mfreeman@mailtribune.com. Follow him on Twitter at www.twitter.com/MTwriterFreeman.