Marine Weather and Tide Forecast for Yoncalla, OR

FXUS66 KMFR 052245 AFDMFR

Area Forecast Discussion National Weather Service Medford OR 245 PM PST Thu Mar 5 2026

DISCUSSION
Northwesterly flow on the backside of an upper trough is keeping 30-60% shower chances in the forecast for the Oregon coast and across Douglas County to the Cascades. In the absence of a lifting mechanism, forecast precipitation amounts remain in hundreths of an inch. Daytime highs remain cool today and warm into Friday but remain below seasonal norms.

With the trough moving farther east and a Pacific ridge expanding to take its place, daytime highs look to be 5 to 15 degrees above normal over the weekend. On Saturday, most west side valleys look to be in the mid to high 60s. Daytime highs east of the Cascades look to be in the low to mid 60s. On Sunday, Oregon counties will see similar highs. Valleys and basins in Siskiyou and Klamath counties are expected to warm to the mid to high 60s. Chances for reaching or exceeding 70 degrees are fairly localized. Per NBM probabilistic guidance, areas in southern Curry County have the highest chances (40-70%) on Saturday. With the warming in northern California on Sunday, chances to exceed 70 degrees shift to Highway 89 (60-80%) as well as around Adin and south of Alturas (20-50% for both areas).

A low pressure system in the Gulf of Alaska could flatten the Pacific ridge to start next week, bringing a zonal flow pattern and a return to generally seasonal temperatures. Moisture being guided into this zonal flow pattern towards the Pacific coast is keeping moderate precipitation chances (40-70%) for the Oregon coast, Douglas County, and the Cascades. There's some variations in long- term guidance in where and when this moisture reaches the coast, with some imagery keeping it north of our area. Without an atmospheric lifting mechanism (like a front or shortwave), orographic features would do the heavy lifting in allowing precipitation to develop. This would keep amounts light where showers do develop, and keep chances low for inland areas. This zonal flow pattern looks to stay in place for much of next week.
There's some uncertainty towards the end of next week as models disagree on whether the Pacific ridge or Alaska low becomes more influential.

One detail that's appearing in some guidance is colder air circling around the Alaska low getting drawn into the zonal flow and moving over the area in the middle of next week. NBM deterministic guidance shows snow levels dropping to 1500-3000 feet across the area through Tuesday and Wednesday. Combined with the moisture entering the zonal flow pattern, these conditions are putting slight chances for light snowfall to reach west side valley floors into the forecast. There's some reason to be skeptical of this outcome. Generally, zonal flow patterns don't support air cold enough to bring low elevation snow.
And more specifically, other conditions are not lining up with snowfall chances. Daytime highs remain in the mid to high 50s in the middle of next week, and overnight lows west of the Cascades stay safely above freezing. The chance of west side snowfall developing is worth mentioning, as slight as it might be. But as of right now, this outcome has very slight confidence in actually occurring.
-TAD
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