textproduct: Medford

DISCUSSION

Forecast confidence has increased in the overall evolution of conditions during the next 10 days. An Air Stagnation Advisory has been issued for the southern Oregon valleys east of the Coast Range through Wednesday afternoon. An active pattern will follow Wednesday night or Thursday through the weekend, and at least into early next week.

A weak shortwave will swing southeastward across Oregon tonight with an increase of high clouds. A few very similar others will follow during the next few days with similarly very modest effect. But, on a broader scale, high pressure will continue to build northeast into the region through Tuesday then linger on Wednesday as it begins to shift eastward. The result is that each of the next few days will have weather that resembles today's conditions. This includes mainly, but not exclusively, west side night and morning valley fog and freezing fog, westside lows mainly in the upper 20s to lower 30s, eastside lows mainly in the teens, mostly clear skies and seasonable temperatures at the coast. Fog and freezing fog will have the hardest time breaking out in Josephine and Douglas counties.

We will start out the first hours of the new year with increasing clouds and an increasing probability of light precipitation. A warm front lifting northward is forecast to result in snow levels around 6000 to 7000 feet. The center of the parent upper trough is expected to track across central California on Thursday, continuing what is likely to become a broader coverage of light precipitation in our area while snow levels remain high.

Beyond Thursday, the finer details of the strength and timing of systems begin to diverge amongst the suite of models. But, a colder, stronger system is expected to track east-southeast from the Gulf of Alaska and across our area during Friday through Saturday. This track brings the highest probability that higher precipitation amounts will be focused on the coast, and western and southern Siskiyou County, secondarily into Josephine County and on the Cascades, with snow levels in our area dropping to more seasonably typical values of around 4000 to 5000 feet. This may be a light event away from the coast and Mt. Shasta region, perhaps not even warranting winter weather advisories elsewhere inland. But, southerly winds will at least become breezy to windy. Details diverge further beyond Friday, but another similar system to its immediate predecessor is likely during the weekend.

AVIATION...29/00Z TAFs

VFR conditions prevail across most of northern California and southern Oregon this afternoon and through the TAF period under stable atmospheric conditions. MVFR ceilings remain in the Umpqua Valley. IFR/LIFR conditions look to return to the Rogue and Umpqua valleys overnight, with clearing possible by Monday afternoon. Slight signals remain for Klamath Falls to see some development early Monday morning fog, but confidence is minimal. Easterly flow will keep fog off the coast. -TAD

MARINE...Updated 200 PM PST Sunday, December 28, 2025

Gusty north winds have produced steep seas mainly across the waters south of Cape Blanco and beyond 10 nm from shore. Gusty north winds and steep seas will expand late this afternoon and evening to include nearly all the waters south of Coos Bay. Conditions improve late Monday, with light south winds expected through Wednesday. Increased south winds begin late in the week ahead of the next series of frontal systems. -BPN

MFR WATCHES/WARNINGS/ADVISORIES

OR...Small Craft Advisory until 1 AM PST Tuesday for ORZ021.

Air Stagnation Advisory until 4 PM PST Wednesday for ORZ023>026- 029>031.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 1 AM PST Tuesday for PZZ350-356-370-376.