textproduct: Medford

KEY MESSAGES

* There is a chance of showers and thunderstorms east of the Cascades and within Siskiyou County late Wednesday afternoon and evening.

* Rain showers remain in the forecast for Thursday with dry conditions along the coast.

* Overnight lows will trend cooler Friday night into Saturday morning with frost and freeze concerns in westside valleys.

* This weekend is looking warner and drier with a low(20%) chance of rain.

DISCUSSION

A mature cyclone continues to move south off the California coastline this afternoon with plenty of mid and high level clouds moving into the forecast area. We're also watching some light east winds over the higher terrain this afternoon continue into tonight. This should keep the boundary layer on the drier side with little to no fog expected along the coast.

By Wednesday, the aforementioned low/cyclone moves into California and it looks like convection kicks off along the Sierras before moving north into our sections of northern California. The rapid refresh ensemble forecast system(REFS) is showing a 40 to 50% chance of cloud to ground lightning over Modoc and Siskiyou County with those probabilities dropping off the farther one moves north. In fact, there is a 10% chance here in southern Jackson County. In summary, we're expecting a 50-60% chance of showers after 5 pm on Wednesday with some embedded thunderstorms. Forecast soundings from the 18Z high resolution rapid refresh(HRRR) model are showing about 200-300 J/kg of convective available potential energy(CAPE) over AAT. The forecast sounding also shows a well mixed boundary layer and skinny CAPE, so we're not expecting any severe storms on Wednesday evening, although some gusty outflows to 35 mph seems reasonable.

The chance of rain will continue into Thursday morning with the PoP forecast persisting over the Cascades and covering locations east of the Cascades. Most locations to the west, including the coast, will remain dry through the event. The PoP forecast here in Medford is about 20% Thursday morning, so there is a chance for some rain here in the Rogue Valley.

By Thursday, models show a short wave pushing this low in California farther eastwards. Models are also suggesting a dry cold front will move through Thursday evening into Friday morning. This will push overnight lows notably lower with freezing temperatures here in the Rogue Valley Saturday morning and potential frost in the Umpqua Valley. A thermal trough will also start to build along the coast with stronger north east flow in the Kalmiopsis wilderness. With a ridge setting up just to our west in the Pacific and a thermal trough lingering in our area, temperatures will warm back into the 70's this weekend. This is a notable change in the ensembles compared to 24 hours ago. There are still a few(~20%) of ensemble members hanging onto rain in the forecast this weekend, so still some variance in the solutions in the day 5 and 6 forecast.

AVIATION...20/18Z TAFs

VFR conditions will prevail through the TAF period with mid-high level clouds over the region. Expect a period of gusty south to southeast winds this afternoon for the Rogue/Shasta/Scott Valleys as well as the Klamath Basin.

MARINE...Updated 200 PM PDT Tuesday, October 20, 2026

Steep swell dominated seas will persist in the outer waters into this evening. Thereafter, improved conditions are expected into Wednesday with sub-advisory north winds and light swell dominated seas. North winds will increase south of Cape Blanco on Wednesday afternoon with seas becoming steep again. A thermal trough is expected Thursday into Friday, with north winds continuing to increase. This may result in steep seas across the waters.

MFR WATCHES/WARNINGS/ADVISORIES

OR...None.

CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 8 PM PDT this evening for PZZ370-376.