Marine Weather and Tide Forecast for Williams, OR

FXUS66 KMFR 281223 AFDMFR

Area Forecast Discussion National Weather Service Medford OR 423 AM PST Sat Feb 28 2026

Updated AVIATION discussion for 12Z TAFs

DISCUSSION
Satellite imagery shows the arrival of cloud cover from the south, indicating a warm and moist air mass that will move over the area today. Most areas will see some light unimpactful rainfall today, with terrain seeing up to 0.33 inches and lower elevations seeing less. Snow levels of 8000-8500 feet will make winter hazards nonexistent. The main concern with this first air mass will be the chance of thunderstorms developing behind the leading edge. SPC paintball guidance for clouds with dBZ > 40 has good agreement with isolated to scattered cells moving across Siskiyou and Modoc counties this afternoon and evening. Paintballs also show a few storms swinging north and passing over Josephine and Jackson counties as well as southern Lake and Klamath counties.
Fortunately, fires are not a significant concern this time of year.
But locally heavy rainfall and gusty winds are worth being aware of, and of course lightning strikes can be a threat to health and property.

Rainfall remains in the forecast for Sunday into Monday as a cutoff low approaches the coast. Rainfall amounts look to be a little higher, but still unimpactful. The Cascades and the Mount Shasta region may see 0.5 to 1.0 inches of rainfall, with other areas seeing less. Snow levels drop to 6500-7000 feet, allowing for light snowfall over peaks and valleys but nothing that should impact area passes. Thunderstorms remain a possibility for Sunday afternoon and evening as well, but current guidance has the cutoff digging farther south and passing over northern California/Nevada. This would keep instability away from the area and more towards Shasta and Tehama counties in northern CA. Ensemble paintballs for the cutoff's passage "hit" a wider area that still includes the CWA, indicating some uncertainty with the low's path and where any thunderstorms will develop on Sunday afternoon and evening.

Rainfall should taper off by Monday afternoon, leading into a mostly uneventful Tuesday as a shortwave ridge passes over the area.
Coastal showers start to develop on Tuesday evening ahead of a cold front that is forecast to bring more precipitation on Wednesday.
Most of the activity is expected along the Oregon coast and over the Cascades north of Highway 140, but forecast amounts for these areas are in the 0.5 to 1.0 inch range which is mostly unimpactful. Snow levels drop to 4500-5000 feet as precipitation is still falling, which may allow for snowfall on Cascades passes. Highway 62 near Crater Lake has a 25% chance of seeing snowfall rates approach 1 inch per hour on Wednesday morning. Total snowfall amounts along the Cascades remain in the 5 to 10 inch range above 5000 feet with marginal snowfall at lower elevations, with a slight trend downward that keeps the higher amounts over peaks and ridgelines.

Uncertainty remains in the forecast behind the Wednesday cold front.
ECMWF deterministic imagery shows a pulse of moisture keeping precipitation in the forecast into Thursday, but meteogram guidance is divided on that outcome. A Pacific ridge looks to develop towards the end of next week. ECMWF guidance expects an upper low to slide along the edge of the ridge and bring another round of precipitation next weekend, while GFS meteograms are generally drier but see that upper low 30% of the time. -TAD
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