textproduct: Medford

KEY MESSAGES

* An uneventful upper pattern will allow daytime highs to drop to seasonal levels, or even a couple degrees below. Coastal areas will see a pattern of marine stratus developing and clearing. Seasonable warm returns to end the week.

* Periods of smoke accumulation are expected for Klamath, Lake, and Modoc counties. Areas around Klamath Falls are likely to see overnight/early morning smoke accumulation.

* Dry and breezy conditions support ongoing elevated fire weather concerns through midweek. Cascades and east side thunderstorm chances to end the week are a part of those concerns as well, but those chances are trending downward.

DISCUSSION

Zonal flow aloft to start the week will allow daytime temperatures to steadily decrease across northern California and southern Oregon. In the middle of the week, past guidance had a trough dropping the Pacific. Recent deterministic imagery has this trough farther east, which would have it descend over the area. While this would not have any significant impacts as far as active weather, a few extra degrees of cooling would let midweek temperatures dip just beneath seasonal norms. For daytime highs, the coast looks to stay in the high 60s to low 70s. West side valleys could dip into the high 80s and east side areas could be in the low 80s. Onshore flow will support a continuing pattern of evening/overnight marine stratus along parts of the coast, with clearing in the late morning and afternoon. This could also bring lower than expected temperatures along the coast if stratus endures into the afternoon.

Atmospheric moisture is still minimal with this pattern, and elevated afternoon breezes are possible as weak disturbances follow the upper flow. With ongoing dry, breezy conditions, elevated fire weather concerns continue. Please see the FIRE WEATHER discussion below for more details.

With the flow pattern looking to stay from the west or southwest, smoke accumulation concerns will continue for Klamath, Lake, and Modoc counties. When winds ease overnight, smoke from the Wrights Spring Fire can settle near the surface. This can bring poor air quality in the early morning far parts of Klamath Falls and along Highway 39/139 past Tulelake. Afternoon breezes look to push smoke to the east, which can bring poor air quality downwind into Lake and Modoc counties. For areas west of the Cascades, some lingering decreased air quality is possible in valleys and sheltered areas as afternoon breezes may not have fully mixed out past smoke.

That change in the trough's position is affecting thunderstorm chances towards the end of the week and into the weekend. With more southwest flow in place, monsoonal moisture becomes mostly cut off from the area. This keeps the highest chances of thunderstorm activity to the southeast or east (Nevada, eastern Oregon). Some slight chances for isolated activity do remain, with weak CAPE (100- 250 J/Kg) and a band of atmospheric moisture indicating possible thunderstorms over western Siskiyou County, along the Cascades, and over northern Klamath/Lake counties. Those slight chances are highest (5-10%) in the afternoon and evening of Friday and Saturday. Confidence in any specific outcome remains low, given the variability in the upper level pattern. More generally, a few degrees of warming may bring weekend temperatures back to seasonal levels. -TAD

AVIATION...10/18Z TAFs

Smoke will be concentrated south and east of the Wright's Spring Wildfire, across southern portions of Klamath and Lake counties, eastern Siskiyou County, and Modoc County. This includes MVFR ceilings and visibility reductions at Klamath Falls late this morning into early this afternoon with improvement to VFR later this afternoon. Smoke is not expected to be as concentrated at Lakeview and Alturas.

Other than the fickle finger of fog near the beaches at Brookings, marine stratus is well offshore and VFR prevails. Strong, north wind gusts up to 35 kt will occur along the coast, including at North Bend, this afternoon and evening. Areas of IFR are likely north of Cape Blanco later this evening into early Tuesday morning.

Otherwise, expect VFR conditions with locally breezy winds this afternoon and evening (gusts of around 20 kt). -Spilde

MARINE...Updated 1100 AM PDT Monday, August 10, 2026

Gusty north winds will continue through Wednesday evening, with gales and very steep seas south of Port Orford and within 40 nm of shore. Elsewhere, steep seas are expected. Winds will begin to ease Thursday, and diminish more noticeably on Friday into the weekend. But, steep seas are likely to linger into Friday.

FIRE WEATHER...Updated 200 PM PDT Monday, August 10, 2026

Main message remains the same -- we expect dry conditions through Wednesday, then slight chances of thunderstorms/lightning in NorCal Thursday. These chances expand up the Cascades and over the East Side Fri/Sat. Latest 12Z guidance has diminished the overall risk/coverage area compared to yesterday, so confidence still remains low, especially with the specifics of where activity will be focused each day.

We'll stay in a pattern of very warm, very dry, and breezy conditions through Wednesday. This pattern includes overnight breezy east to northeast winds at ridge tops of SW Oregon and NW California (most notably the Coast Range and Kalmiopsis Wilderness) along with poor to moderate RH recovery tonight/Tuesday morning, trending to improved but still moderate recovery in subsequent mornings. A channeling of winds down the Chetco could result in some drier/warmer conditions along the SW Oregon coast as well (though the marine influence has held so far at the beaches).

The trend through midweek will be to lower daytime MaxTs down by a degree or two each day, and this should subsequently allow daytime MinRHs to be slightly higher. Even so, it'll be dry and unstable, so any fires on the landscape will still have the ability to grow significantly, especially during the peak burning periods during the afternoons/evenings. Overnight RH recoveries haven't been good the last couple of nights, generally only in the 20-35% range for some of the upper slopes and ridges. There should be slight nightly improvement in recoveries from NW to SE through the period. Things trend toward normal after Wednesday, but temperatures still probably remain a few degrees above normal for most locations.

Models and ensemble guidance continue to show a weakness or upper trough developing near the California coast Wed/Thu and also show an increase in monsoonal moisture coming up from the south late week. Models are a bit farther east with their depictions today, so this would keep the flow more SW (as opposed to due S). As such, coverage area and risk has diminished since yesterday. There's about a 5-10% probability of a thunderstorm extending into southeast Modoc County on Wednesday afternoon, but 10-20% chance into NorCal Thursday pm/eve with the best chance for isolated thunderstorms Fri/Sat from NorCal up the Cascades and across portions of the East Side. Given plenty of uncertainty in strength of forcing mechanisms, overall instability and moisture advection, confidence is low in the locations where activity will be focused. Keep checking back for updates since any lightning brings with it the risk of new fire starts. -Spilde

MFR WATCHES/WARNINGS/ADVISORIES

OR...CA...None.

PACIFIC COASTAL WATERS...Gale Warning until 11 PM PDT Wednesday for PZZ356-376.

Small Craft Advisory until 11 PM PDT Wednesday for PZZ350-356- 370-376.