textproduct: Medford

AVIATION (18Z TAFs)

The marine layer is expected to continue to dissipate this afternoon with VFR conditions through this evening, but we are expecting the marine layer to reestablish overnight bringing IFR/LIFR conditions. Otherwise, expecting VFR conditions for inland sites with a couple nuances. Roseburg may see some of this marine layer influence tomorrow morning similar to this morning, but should remain in VFR as clouds should be thin. We may continue to see smoke impacts for KLMT with haze and perhaps some ceiling influence as well.

-Guerrero

PREV DISCUSSION

/Issued 725 AM PDT Wed Aug 12 2026/

KEY MESSAGES...

* Seasonable warmth and breezy afternoons/evenings are expected for the next week, with inland highs a couple to several degrees cooler today and generally near normal for the first time in the past 10 days.

* Smoke accumulation will be focused east and northeast of Klamath Falls into Lake County this morning, with some improvement as late day winds blow smoke to the east. A thicker concentration for Klamath and Lake counties and into Modoc County is forecast to arrive after midnight, with smoke from north central Oregon, as well as from the Wright's Spring wildfire.

* A few cumulus buildups for northern Lake and western Siskiyou counties this afternoon will be the first sign of increasing instability. Slight chances of thunderstorms remain in the forecast for each afternoon and evening from Thursday through Saturday, with a focus on northern portions of Klamath and Lake counties, secondarily for both western Siskiyou County into southwest Jackson County, and eastern Modoc County.

* There is a high level of uncertainty in the convective forecast beyond the weekend. Further thunderstorms chances could develop as early as Monday, but the risk will trend to a peak on Wednesday with greater/scattered coverage of wetter storms as a possibility.

DISCUSSION...The axis of a sharpening upper level trough was offshore yesterday, and pushed inland overnight with low clouds for the coast and coastal valleys. The slow, very gradual cooling trend is still expected to continue today into the weekend, with afternoon high temperature readings that were around 2 to 6 degrees above normal yesterday expected to be near normal today. The two most consistent aspects of the forecast during the next week will be: low clouds and patchy fog at the coast north of Cape Blanco, with some improvement for the afternoons. Also, breezy afternoons and evenings across the area.

A shortwave rotating through the base of the trough is expected to be the trigger for isolated thunderstorms in northern portions of Klamath and Lake counties on Thursday afternoon, from around Valley Falls northward. Weaker instability may still be sufficient for thunderstorms also to form in a vicinity around Fort Jones to Yreka, and also in southeast Modoc County.

A stronger disturbance is expected to carve out a wave with its axis offshore on Friday. This will lead to a broader area of instability, still focused on northern portions of the east side, but extending farther back to the Cascades/Crater Lake, a broader portion of eastern Modoc County, and from western Siskiyou County into southwest Jackson County (including the Applegate Valley).

The region of greatest instability is likely to shift east and northeastward out of our area on Saturday, but a slight chance lingers for northern Klamath and northern/eastern Lake counties.

A risk cannot be completely ruled out for Sunday, but either a brief period of ridging, or eastward progression of the Pacific trough would lead to a break in the action for our area.

The model differences increase further on Monday, but a trough moving southeast from the Gulf of Alaska is likely to dominate the pattern early in the week. This will bring an influx of high clouds, and possibly shower and thunderstorm chances. The contingent of GEFS and ECMWF ensemble members that indicate some 15% or higher shower and thunderstorm risk in some portion of our area builds from around 10% of members on Monday, 10-15% on Tuesday, and 20-40% on Wednesday.

AVIATION (12Z TAFs)... The coastal marine layer is producing LIFR into the coastal valleys. It will be at its thickest this morning, and again overnight into Thursday morning, extending into the Camas Valley and with patches of low clouds early in the central Umpqua Valley (including Roseburg). Improvement is expected late this morning into the early evening, though with patches of LIFR persisting through the day north of Cape Blanco.

We will also continue to see smoke from the Wright's Spring Fire impact areas from southern Klamath County eastward into Lake County, with some ceilings and reduced visibilities at times, including at Lakeview. Improvement is expected this afternoon into the evening with the aid of westerly breezes, but a thicker concentration of smoke is expected for Klamath and Lake counties into northern Modoc County overnight into Thursday morning. There remains a lot of uncertainty with smoke forecasting due to fire activity/suppression efforts. Otherwise, expect VFR conditions for other inland areas and typical diurnal breezes.

MARINE...Updated 230 AM PDT Wednesday, August 12, 2026...Gusty north winds continue through this evening, with areas of gales and very steep seas south of Port Orford and steep seas to the north. Winds will begin to ease Thursday, with north winds at Small Craft Advisory strength south of Port Orford. But, with the combination of wind wave and fresh swell, steep seas are expected across all of the area on Thursday, and may persist into Friday morning. Weak winds and low seas are expected for the weekend into early next week.

FIRE WEATHER...Updated 200 AM PDT Wednesday, August 12, 2026... Breezy afternoon winds will accompany seasonably warm and dry conditions today. Aside from temperatures returning to near normal for the first time in 10 days, weak instability this afternoon should be enough for low topped cumulus buildups over the higher terrain in northeast Lake County and western Siskiyou County.

Breezy afternoon winds and near normal temperatures are expected to continue over the next week, but a slight chance of thunderstorms is expected each afternoon/early evening for portions of the area Thursday through Saturday. The focus for development looks to be in the northern portions of Klamath and Lake counties, with a lesser probability for western Siskiyou County into southwest Jackson County, and eastern Modoc County. Shower and thunderstorm chances may return as early as Monday, but the slight chance probability trends higher to a peak on Wednesday.

MFR WATCHES/WARNINGS/ADVISORIES

OR...CA...None.

PACIFIC COASTAL WATERS...Gale Warning until 2 AM PDT Thursday for PZZ356-376.

Small Craft Advisory until 2 AM PDT Thursday for PZZ350.

Small Craft Advisory until 5 PM PDT Thursday for PZZ356-370-376.