Marine Weather and Tide Forecast for Winchester Bay, OR

FXUS66 KMFR 122004 AFDMFR

Area Forecast Discussion National Weather Service Medford OR 104 PM PDT Sun Apr 12 2026

DISCUSSION

Showers are starting to pop up on radar this afternoon as this low traverses out forecast area. Daytime heating is helping create some instability out there and we should shower coverage continue to increase with perhaps a few embedded thunderstorms. The probability of cloud to ground lightning is about 20% today mainly in California and near the California/Oregon border.

This upper level low eventually lease the forecast area tonight, although there are short waves dropping down from the north west later tonight into tomorrow morning. Main impact will be the continued 50-60% chance of showers on Monday. However, the areal coverage will be lower compared to what we've seen over the last few days. The probability of rain decreases Monday night into Tuesday as high pressure briefly builds. Temperatures remain near normal on Tuesday with some cloud cover entering the forecast ahead of the next system.

By Tuesday night into Wednesday morning, a deep trough and strong cold front will descend upon the Pacific Northwest. Main impacts will be snow accumulation over the higher Cascades Tuesday night into Wednesday morning above 5000 feet. We've issued a winter storm watch because of this threat. Snow levels will drop lower than 5000 feet between Tuesday night through Wednesday, although snow should struggle to accumulate due to warmer ground temperatures with minor snow accumulation around 3500 feet.

The other thing that pushed us to issue a winter storm watch was the extreme forecast index(EFI) painting values of 0.8 along the Cascades. Also, snowfall rates could reach 1" an hour for 6 to perhaps 12 hours along the front. A prolonged period of snowfall rates usually results in some travel impacts. Overall, not a massively impactful storm, although the time of year and the near 1 foot of snow at Crater Lake pushed us towards a winter storm watch. The warmer ground temperatures could really limit the amount of snow accumulation on the other hand like the last event. We'll have to wait and see.

Eventually, the cold front will pass through our forecast area Wednesday afternoon and the precipitation mode will turn showery with minor snow accumulations in the Cascades. The important note will be the colder temperatures moving in behind the front as snow levels crater to 1700 feet!

Usually, we see high pressure set up behind these fronts with a strong inversion build in. However, this looks a bit different as the very cold air off the Ocean should allow for pockets of showers to form with some cloud cover. Temperatures in northern California will drop below freezing due to clearer skies in those valleys. West of the Cascades in Oregon is more uncertain at this time. The chance for Medford to drop below 32F is 34%. The threat of cold overnight lows will continue Thursday night. Conditions are anticipated to remain dry Thursday through Friday before the next system approaches by Friday.
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