textproduct: Medford

Updated AVIATION Discussion

AVIATION...18/00Z TAFs

VFR skies will prevail across most of the area through the TAF period. The exceptions to this will be areas of heavier smoke, particularly for the Rogue Valley, including Medford, where MVFR visibilities are expected to persist. There could be a brief period of improved conditions, but it will be short-lived as north-northwest winds bring thick smoke back into the valley. Portions of the Klamath Basin, including Klamath Falls, will see periods of smoke as well, primarily in the afternoon/evenings after winds shift to the northwest.

The other exception will be marine stratus along portions of the coast and offshore as IFR ceilings and visibilities to return in the late evening and overnight across the entirety of the coast.

PREV DISCUSSION

/Issued 207 PM PDT Fri Jul 17 2026/

KEY MESSAGES...

*Critical fire weather conditions expected Friday (7/17) afternoon and evening for portions of the Shasta Valley, eastern Siskiyou, Modoc, southeast Klamath and southwest Lake Counties.

* Hot, dry, breezy, unstable conditions will continue each day through the weekend.

*Smoke will persist for Jackson and Klamath Counties through the weekend.

*Thunderstorms re-enter the forecast beginning as early as Monday, mainly for the Cascades and east. Lesser chances beginning Tuesday for areas west of the Cascades.

DISCUSSION...Satellite imagery shows mainly cloud free skies across southern Oregon and northern California. However, the satellites are picking up on infiltrating the Rouge Valley from the East Evans Creek Fire. This smoke is creating significant air quality concerns and the Oregon Department of Environmental Quality has issued an Air Quality Advisory for Jackson, Klamath, and northern Lake Counties through at least noon Monday. The HRRR smoke model continues to show smoke impacts through the weekend. While the smoke is not great in general, it does come with a couple of benefits. Afternoon high temperatures may be a little lower than forecast, and winds and instability will dampen somewhat in the areas of heavy smoke.

A warming and drying trend will begin this weekend as a low pressure system moving into Canada will continue to move away from southern Oregon and northern California. This will bring in general deep southwest flow as the 4 corners ridge builds in again. With the warming and drying trend, winds will also trend weaker this weekend.

Then on Monday, confidence in the forecast decreases as another low looks to dig in off the west coast and be juxtaposed with the 4 corners high. Depending on the location and timing of these larger scale features a few different scenarios could happen. Should the ridge build farther west, we could look for much warmer temperatures through the week bringing hot, dry, breezy and unstable conditions to the area. Should the high push farther east with the low closer to us, this could tap into some deep moisture bringing thunderstorms chances to areas along and east of the Cascades beginning as early as Monday (but more realistically Tuesday and Wednesday). These storms could even push west of the Cascades on Tuesday and Wednesday, but ensembles do not necessarily favor this solution as the NBM continues to to favor a 5-15% chance for storms.

MARINE...Updated 200 PM PDT Friday, July 17, 2026...Increasing north winds will build steep seas south of Cape Blanco this afternoon, with steep seas spreading to all waters on Saturday. As north winds peak late Saturday and Sunday, areas of very steep seas may develop south of Port Orford. Conditions gradually improve on Monday, but steep seas may linger with the dominant wind waves transitioning to fresh swell. Improved conditions are likely on Tuesday. A low pressure may move up from the south late Tuesday and Wednesday. This low may remain well offshore and weaken as it moves north. It will bring chances for 3-6 ft southerly swell and chances for showers.

FIRE WEATHER...Updated 200 AM PDT Friday, July 17, 2026... The two main aspects of the forecast for particular analysis this afternoon were the extent of hot, dry, and breezy/windy conditions today through Sunday, and the potential risk and coverage of thunderstorms while inland temperatures remain above normal during Monday through Wednesday.

A Red Flag Warning continues this afternoon and evening, remaining in effect for southwest Lake and southeast Klamath counties, and zone 285 in Modoc County and much of central and eastern Siskiyou County (Zones 281 and 284). The strongest south winds of this event are expected to occur for the eastern portion of the Shasta Valley. A slow moving dry front will winds to a peak of strength in the late afternoon.

The forecast through the weekend is consistent and pretty straight- forward. Temperatures will trend upward, humidities will remain drier than normal, and afternoon winds will trend back to typical strength for Sunday. That being said, areas of heavy smoke from the East Evans Creek fire may dampen some of the winds and instability.

Hot, dry, and breezy conditions are expected Saturday and Sunday. Temperatures of 5 to 10 degrees above normal are expected through the weekend. Afternoon wind speeds will trend back to typical values by Sunday. Minimum afternoon humidities will remain very low on Saturday then trend slightly upward on Sunday. The slight moistening of the air mass on Sunday will be accompanied by a late day increase of high clouds, and perhaps some east side cumulus buildups. The majority of ensemble solutions favor the hotter, drier ECMWF. But, there is about a 20% probability of a slightly less hot, but noticeably more moist air mass as depicted by the operational GFS run.

In that case, instability could develop as early as late Sunday night into Monday morning, with a few very light showers or virga possible over the higher terrain. A risk of thunderstorms could develop as early as Monday afternoon, with a higher probability of thunderstorms, highest for Lake and Modoc counties, on Tuesday and Wednesday afternoons. Though not as indicated by the GFS, a more expansive analysis shows chances for Monday thunderstorms remain very slight (5-10%) and predominantly over the east side. On Tuesday, 10-15% chances cover most of the east side, with a lesser 5% to 10% probability extending into Jackson, Siskiyou, and eastern Douglas counties. Particularly if the GFS were to verify, for areas where thunderstorms do not develop, the potential instability added to continuing hot and dry conditions could lead to elevated critical condition concerns and enhanced behavior on existing fires.

Model uncertainty still increases further beginning Wednesday with differences in whether an unstable air mass will linger or shift east of our area. Late in the week (Thursday/Friday), some eastward movement in the pattern is likely, which is likely to shift the region of instability east of our area. But, with a plausibly slower solution keeping instability over eastern portions of Lake and Modoc counties.

MFR WATCHES/WARNINGS/ADVISORIES

OR...Red Flag Warning until 8 PM PDT this evening for ORZ624.

CA...Red Flag Warning until 8 PM PDT this evening for CAZ281-284-285.

PACIFIC COASTAL WATERS...Small Craft Advisory from 11 AM Saturday to 11 PM PDT Sunday for PZZ350-356-370-376.

Hazardous Seas Watch from Saturday afternoon through Sunday evening for PZZ356-376.