textproduct: Medford

KEY MESSAGES

* Showers continue today, with isolated to scattered thunderstorms possible.

* Temperatures remain 15 to 25 degrees below normal, with gradual warming through the weekend and into early next week.

* A few stray showers are possible Saturday, then activity will increase again Sunday with another slight chance of thunderstorms. The probability for thunder will be highest in and near the Cascades.

* More seasonable September weather returns with a warming trend Monday through midweek.

* Higher uncertainty late next week, but with another episode of wet to very wet weather possible.

DISCUSSION

Looking out the window or stepping outside today, one would have a hard time reconciling the experience with the current date on the calendar. While it is officially September 4, the extensive cloudiness, widespread showers, and cool temperatures would suggest it might instead be early November. A look at some of our higher elevation webcams and peaks would likely lead to further confusion, with snow being spotted along the rim of Crater Lake and on the peaks of other mountains in the Cascades, including a very bright white snowcap on Mount Shasta. Not our typical Labor Day weekend weather, to say the least!

Satellite imagery this afternoon shows a very tight swirl of clouds just offshore of Florence, along with plenty of clouds on the broader scale streaming onshore and across souther Oregon and far northern California. This swirl marks the position of a surface low, the culprit that brought us these much cooler temperatures and wetting rains. Showers will continue through this evening for much of the area while this low slowly drifts onshore, then moves off to the northeast tonight. As a result, the area will see a significant reduction in shower chances Saturday, and temperatures will bump up a bit, but still remain below normal for this time of year.

Another lobe of upper level energy, associated with the upper level closed low, will swing through the region Sunday, producing another day of widespread showers and potential isolated to scattered thunderstorms, resulting from instability developing between the relatively warmer air in the lower levels, and the much colder air aloft. With the extensive clouds cover and showers, temperatures will be cooler again, back to similar values as those of Thursday and Friday.

The upper level trough finally lifts to the northeast Monday. Meanwhile, another trough will dig south offshore of the West Coast, eventually setting up as a closed low somewhere off of California, while ridging develops over the Four-Corners region to the southeast. Although weaker than most ridges the past several months, a lobe of the ridge will build northwest along the Sierra Nevada and into southern Oregon, resulting in warming temperatures and bringing an end to shower chances.

It is here that model guidance begins to diverge significantly, mainly in regards to where the offshore low ends up, and how strong the ridge becomes. These two factors will have a big impact on the resulting weather in our area for the remainder of the week. A stronger low centered farther south off of California will result in a stronger ridge over our area, with temperatures warming to right around normal for this time of year. A weaker low farther north and closer to our area will result in a weaker ridge, with continuing below normal temperatures, but still warmer than the past several days. Either way, more seasonable conditions are expected, and hopefully the details will become clearer over the next few days.

Another factor worth mentioning is the potential, albeit small, of tropical influence in the long term forecast. If the offshore trough sets up farther south, if it is strong enough to influence the broader steering flows, and if the timing/track of Hurricane Marie (or rather, the remnants thereof) line up with the progression of the upper air pattern, tropical moisture could be funneled up along the eastern periphery of the offshore trough, and quite literally dumped somewhere over California or Oregon late next week. The chances of this scenario are low, with the above factors having to be aligned just right, but it is possible. Much like a baking a cake, you need the right ingredients in exactly the right amounts, or you end up with something different than you expect. Several members of the model suites have been depicting this scenario over the past day or two, so we will keep a close eye on things as there would be significant impacts should the event come to pass.

On a much less interesting/exciting note, but still continuing our trend of unusual weather for early September, even if the above scenario does not occur, nearly all model guidance shows another upper level trough digging south by the end of the week, bringing cooler temperatures and additional beneficial rains to the Pacific Northwest. -BPN

AVIATION...04/18Z TAFs

VFR levels are generally present across northern California and southern Oregon, with MVFR ceilings persisting along the coast. Scattered showers continue west of the Cascades, which may bring periods of lower ceilings and visibilities as well as obscured elevated terrain. Thunderstorm chances will be present this afternoon and evening, with the highest chances (20- 40%) over Coos, Douglas, and northern Klamath counties. Neighboring areas will have a 10-20% chance of thunderstorms. Shower and thunderstorm chances decrease into the nighttime hours.

While active weather is not expected on Saturday, MVFR to IFR ceilings and visibilities are possible for coastal areas early Saturday morning. Anything that develops overnight will likely dissipate before Saturday afternoon. -TAD

MARINE...Updated 100 PM PDT Friday, September 4, 2026

A surface low continues to meander just offshore of southern Oregon, but will gradually pass onshore through this evening. As a result, winds will diminish today into tonight, then shift to the north Saturday. Light winds and relatively calm seas are then expected through the weekend, along with periods of showers. A weak thermal trough develops Monday into Tuesday, with gusty north winds and steep seas possible south of Gold Beach. Conditions are likely to improve again mid to late week.

MFR WATCHES/WARNINGS/ADVISORIES

OR...CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until noon PDT today for PZZ350-356-370-376.