Strong Atmospheric River to Bring Heavy Rain North as Rogue Valley Stays Mostly Dry

MEDFORD, Ore. (Dec 6, 2025) — While subtle adjustments have been made to the regional forecast, meteorologists say the overall message remains unchanged: southwest Oregon and northern California will avoid the brunt of a strong atmospheric river expected to drench areas farther north through the middle of next week.

Forecasters with the National Weather Service said Saturday that an upper ridge off the California coast continues to act as a barrier, pushing the main plume of subtropical moisture into northwest Oregon, Washington and British Columbia. Those traveling north should be prepared for soaking rains, with flood watches already posted from the Willamette Valley to the Canadian border.

The frontal boundary feeding the atmospheric river is expected to wobble north and south multiple times through at least Wednesday. That pattern will bring periods of moderate to occasionally heavy rainfall to the northwest portion of the Medford forecast area — mainly Coos, Douglas and parts of Curry counties — with projected totals ranging from 1 to 4 inches.

South and east of the Rogue-Umpqua Divide, conditions will look starkly different. Many communities will see little or no rainfall, and portions of northern California, including eastern Siskiyou and Modoc counties, may remain completely dry.

A warm front is forecast to move into the region late Saturday, bringing renewed chances of steadier rain to northwest counties Sunday into Monday. However, most precipitation is expected to remain north of the Oregon-California border, and Medford is not currently projected to receive measurable rainfall. From the coast to the Cascade foothills, forecasters say amounts could range from 0.10 to 0.50 inch, with slightly higher totals possible in terrain-enhanced areas. Snow levels will rise to between 7,000 and 8,000 feet.

Forecasters are watching the period from Monday night through Wednesday closely as the front shifts south again. How far it settles remains uncertain. The GEFS model suite is more aggressive in pushing moisture toward the border, while the ECMWF keeps the heaviest rain north. If the GEFS scenario plays out, winds could also increase across the east side, with one deterministic model showing a strong 700-millibar jet capable of producing wind advisories north of Highway 140.

By late next week, models show the frontal boundary lifting northward once more, allowing the coastal ridge to re-amplify. That pattern could deliver a mild, dry stretch across much of the region heading into next weekend. The Climate Prediction Center’s Week 2 outlook continues to favor above-normal temperatures and slightly increased chances of near- to above-normal precipitation, depending on how firmly the ridge holds.