textproduct: Medford

Updated AVIATION Discussion

AVIATION...27/12Z TAFs

IFR/LIFR stratus and fog will persist along the coast through the morning, gradually becoming VFR by late morning/early afternoon. The marine layer has pushed inland, bringing low end VFR/MVFR conditions to the Umpqua Basin. There is some spill over occurring and it's possible (15% chance) for some low end VFR stratus here in the Rogue Valley around sunrise.

Other than some high cirrus, VFR will prevail for the rest of the area through this evening. Gusty west to southwest winds will return this afternoon/evening east of the Cascades (east of Klamath Falls) and in NE California with peak gusts in the 25-35 kt range.

Expect marine stratus to return to the coast and also portions of the Umpqua Basin tonight.

PREV DISCUSSION

/Issued 240 AM PDT Thu Aug 27 2026/

KEY MESSAGES...

* Heightened fire weather concerns across the East Side through this evening due to gusty winds and low RH.

* Weak instability just clipping far southeast portions of Modoc and Lake counties for a slight chance of showers/thunderstorms late in the day on Friday.

* Temperatures trend cooler into Saturday, and remain near or below normal for the next week.

* Weather pattern largely influenced by upper level troughing, resulting in gusty winds in the afternoons/evenings, and night and morning coastal stratus extending into the Umpqua Valley for the early morning hours.

* Strong troughing Tuesday through Thursday next week maintains below normal temperatures and brings rain chances, with the highest probabilities along the coast and into the Umpqua Basin.

DISCUSSION...Model agreement/confidence in the forecast is high through Tuesday. Southwest flow continues over the region as an upper level trough continues pushing inland over the Pacific Northwest. This trough will linger near the Canadian border through Saturday. After a brief period of ridging/slight warming and drying on Sunday, a stronger trough will track southeastward from Alaska beginning Monday and linger through at least Tuesday. Model agreement on the progression/details of this trough from late Tuesday onward varies, but there's general agreement on a continued trough pattern through the end of next week.

Over these next several days, the cooling trend and gusty afternoon and evening winds will continue. This will continue to bring heightened fire weather concerns today, with stronger winds and RHs remaining fairly low. Fire weather concerns diminish some Friday onward as RHs trend higher, but with afternoons remaining breezy, and no precipitation expected (at least into Tuesday), fire danger remains very high across the region. Please remember to do your part and prevent a spark. One less spark, one less fire.

For most of the forecast period, the mid-levels will be too dry to support any thunderstorm development. The exception will be on Friday as remnant tropical moisture gets swept into the westerlies. Guidance remains steadfast with the trajectory of this moisture, bringing it into central CA/northwestern Nevada. This will clip the southeastern portions of Lake and Modoc counties, bringing some scattered showers and isolated thunderstorms Friday afternoon/evening.

A more elongated trough will approach the coast from the northwest on Monday, moving inland on Tuesday. This will likely be another wind maker for the region, especially east of the Cascades, but it will also start a period of increased precipitation chances, primarily along the coast and north of the Rogue-Umpqua Divide. We'll need to monitor the potential for heightened fire weather concerns on Monday due to gusty winds, but RHs may be high enough to limit this.

Despite the differences in the guidance on the progression of this trough, there is fairly good agreement (for this time frame in the forecast) that an overall deeper trough will be over/in the vicinity of the Pacific Northwest late Tuesday through at least Friday. The vast majority of ensemble members bring measurable precipitation to the coast during this time, with a sizable majority of the members showing measurable precipitation even for Medford (the 00z/27 EC suite is more bullish with this compared to the GEFS suite). Given the time of year, one tends to be skeptical of this coming to fruition, especially since often times, we see these precip chances lower as the time gets closer, or get pushed later in time over future model runs. But, ensembles have steadily been showing this potential for precipitation in the region. Still, confidence is low on the inland extent for rainfall, and any rainfall looks to be generally light with the higher precipitation chances expected north of the forecast area. Confidence is higher, however, for continued cooler temperatures next week, with high temperatures currently forecast to be 5 to 10 degrees below normal.

MARINE...Updated 1200 AM PDT Thursday, August 26, 2026...Relatively calm conditions with light winds and low seas are expected into Friday morning. Southerly winds will persist through this morning, then turn northerly by this afternoon. North winds increase on Friday with steep seas developing south of Cape Blanco in the afternoon, then persisting through the weekend. Winds will be strongest Saturday and Sunday during the afternoon and evening hours. Conditions are likely to improve Monday into Tuesday.

FIRE WEATHER...Updated 200 AM PDT Thursday, August 27, 2026...Critical fire weather conditions will continue across the East Side today as an upper level trough continues moving inland. Gusty winds will trend a bit stronger today (gusts 30-35 mph, possibly up to 40 mph in the windiest spots) and daytime humidities will remain low (single digits to low teens). A Red Flag Warning remains in effect for the southern portions of Fire Weather Zones (FWZs) 624/625 and most of 285.

Aside from a brief period of ridging/slight warming and drying on Sunday, upper level troughing will dominate the weather through the forecast period. This will maintain gusty afternoon/evening winds, though generally weaker than today/recent days. Additionally, RHs will trend higher as temperatures continue trending cooler, and this will limit critical fire weather conditions after today.

Meanwhile, onshore flow will generally maintain moderate to good recoveries with nightly marine pushes for coastal zones. The exception to this will be this morning when poor recoveries are expected along the Warners and southern portions of the Fremont- Winema National Forest.

A slight chance of thunderstorms was added to the forecast for Friday for southeast portions for FWZs 652/285. Guidance maintains an area of remnant tropical moisture moving into central CA/northwest NV, which looks to clip the southeastern portions of the region, bringing some showers and isolated thunderstorms Friday afternoon/evening. The better instability and greater thunderstorm coverage should remain south and east of the region. Drier air in the mid-levels returns Saturday and thunderstorms shift eastward.

A stronger trough arrives next week, maintaining cooler/below normal temperatures, higher humidities and bringing the potential for rainfall primarily along the coast and into the Umqpua Basin. See the discussion above for more details.

MFR WATCHES/WARNINGS/ADVISORIES

OR...Red Flag Warning from 2 PM this afternoon to 8 PM PDT this evening for ORZ624-625.

CA...Red Flag Warning from 2 PM this afternoon to 8 PM PDT this evening for CAZ285.

PACIFIC COASTAL WATERS...Small Craft Advisory from 2 PM Friday to 5 PM PDT Saturday for PZZ356-376.