textproduct: Medford

KEY MESSAGES

*Cool temperatures with scattered showers from the Cascades south and east into Monday evening (focused in NorCal). *Isolated t-storms in NorCal this evening. *Seasonable elsewhere with isolated showers. *Nighttime/morning clouds/drizzle along coast/coastal valleys north of Cape Blanco, may reach Roseburg at times Mon/Tue. *Shower activity shifts southeastward Tuesday. *Warming trend Wednesday-Friday. *More active next weekend?

DISCUSSION

An upper trough is overhead today and this is resulting in widely scattered showers and even some isolated thunderstorms. The focus for activity will be in NorCal through late this evening, but isolated showers could pop up here or there in SW Oregon as well. This is being supported by colder air aloft associated with the trough, modest moisture in the mid-levels and resultant weak instability of 100-250 J/KG. Expect activity to decrease overnight as instability wanes. Marine layer will deepen again tonight with clouds/fog and perhaps even spotty drizzle impacting the coast/valleys north of Cape Blanco. Some of this may spread into the Umpqua Basin toward morning, but should break up into stratocumulus and peel back closer to the coast Monday afternoon.

Meanwhile, the main upper trough axis will shift east of the Cascades on Monday as an upper disturbance drops southward just off the coast. Some moisture/weak instability will linger across the area, so still expect at least isolated showers to develop from the Cascades south and east Monday afternoon/evening. Temperatures through Monday will be cooler than normal for most, but seasonable west of the Cacades.

On Tuesday, shower chances drop out of the forecast, but there is a low percentage of members (about 10%) that produce showers across SE Siskiyou/Modoc counties. Most areas see modest warming (about 3-6F) compared to Sun/Mon.

An upper ridge is then expected to move in mid-late this week bringing a period of dry and warmer weather with high temperatures (areas inland from the coast) generally 10-15F above normal for late April and early May. This means high temperatures ranging from 75-85F for most inland west side valleys. Coastal areas could continue to experience intrusions of late-night/morning marine stratus.

Models then show the ridge breaking down by this weekend as an upper trough just off the West Coast tries to close off offshore. An increasing number of solutions show the low closing off to our SW, which would bring an increased risk for mainly afternoon and evening showers and thunderstorms Saturday, with the potential for active weather persisting Sunday into early next week. Much will depend on the eventual track of trough/low, however. Many members, particularly from the GEFS ensembles, maintain a weaker trough moving through, which would limit the overall extent/coverage of precipitation. We'll adjust the forecast as things come more into focus. -Spilde

AVIATION...26/18Z TAFs

Onshore flow is bringing MVFR ceilings to the Oregon coast. The MVFR ceilings will begin to break up with sufficient surface heating this afternoon along the coast. Look for those MVFR ceilings to build back in later this evening and persist overnight. Some pockets of drizzle are also possible later tonight. There is a 50% chance that some of these lower clouds are able to make it to Roserburg and produce more MVFR ceilings in the Umpqua Basin.

In northern California, there will be a low chance of showers and perhaps thunderstorms later this afternoon. The chance of storms will diminish by the late evening hours.

-Smith

MARINE...Updated 200 PM PDT Sunday, April 26, 2026

North winds will persist through the week with a low north west swell keeping seas around 5 to 7 feet.

Northerly winds increase again late Tuesday, especially south of Cape Blanco, and persist through much of the week. High and steep seas are likely Wednesday night into Saturday as this a thermal trough builds in along the coast.

-Smith

MFR WATCHES/WARNINGS/ADVISORIES

OR...None.

CA...None.

PACIFIC COASTAL WATERS...None.