textproduct: Medford

KEY MESSAGES

* Daytime highs of 5 to 15 degrees above normal present Advisory- level conditions for most areas this afternoon and evening as well as on Thursday.

* Smoke from area fires may accumulate in the morning hours, with improvement as afternoon breezes develop.

* Cooling is possible over the weekend and into next week, but dry air aloft keeps precipitation out of the forecast.

DISCUSSION

High pressure remains in control of conditions across northern California and southern Oregon today. For areas west of the Cascades, daytime highs this afternoon and evening will be very similar to Tuesday's. To the east, daytime highs look to rise about 5 degrees to the mid to high 90s. As these temperatures present the risk of heat-related illnesses to anyone who is sensitive to or unprepared for them, a Heat Advisory has been issued for most inland areas today. With daytime highs of 5 to 15 degrees above normal continuing into Thursday, this Advisory continues as well, with only the Umpqua Valley dropping out as temperatures look to ease just enough to drop below Advisory thresholds.

Wildfire smoke also remains in the forecast for today, as gentle winds overnight look to allow for smoke to settle over Oregon counties and just into northern California counties early this morning. Once again, afternoon breezes will help to clear smoke out somewhat. Current modeling shows smoke accumulation on Thursday as well, but at decreasing concentrations. The combination of high temperatures and poor air quality may make being outside especially uncomfortable for sensitive individuals.

Warm temperatures look to continue into Friday, although a few degrees of cooling is possible. Upper ridging looks to flatten by Saturday, bringing westerly zonal flow aloft. This looks to start a cooling trend that will bring most areas to seasonal norms through the middle of next week. In spite of this pattern change, the atmosphere looks to stay fairly dry which will help to keep thunderstorms out of the forecast. Models show some uncertainty beyond the forecast period, with variations in expected temperatures but no expectation of precipitation in either the GFS or ECMWF models. -TAD

AVIATION...05/12Z TAFs

VFR levels continue across the area early this morning, with signs of some development around North Bend possibly lowering levels. As of right now, this development has not yet solidified at the terminal. A "sunrise surprise" of MVFR/IFR levels is possible, but would clear out fairly quickly this morning. In general, VFR levels are expected through the day today although smoke accumulation may make brief periods of MVFR visibility's possible at area terminals. A more robust marine layer is expected this afternoon and evening as onshore flow develops, bringing IFR/LIFR levels to coastal areas. -TAD

MARINE...Updated 830 PM PDT Tuesday, August 4, 2026

Conditions remain hazardous to small craft through early this morning as steep seas persist with gusty northerly winds. Conditions will likely improve later today into Thursday with lower wave heights due to north wind waves and fresh swell. North winds are expected to strengthen again Friday through the weekend, with steep seas likely south of Cape Blanco.

FIRE WEATHER...Updated 400 AM PDT Wednesday, August 4, 2026

Ridging aloft and a thermal trough at the surface will produce persistent near-critical to critical fire weather concerns through the week. Temperatures will remain hot through the week, peaking at about 10 to 15 degrees above normal Wednesday/Thursday, before cooling slightly to more normal or just slightly above normal values into the weekend and early next week.

Poor RH recoveries have been observed across all of SW Oregon and northern California upper slopes/ridges early this morning. Some guidance is showing RH only recovering into the low 20s (upper teens?!) through Thursday, while daytime minimum humidities could easily drop into the single digit percentages. With these hot, dry, and windy conditions in the valleys during the day today and Wednesday, we are expecting to reach critical conditions across much of the area. A Red Flag Warning is in effect for the Illinois and Rogue valleys, as well as the Siskiyous and southern Oregon Cascades through this evening, with another Red Flag Warning issued for these same areas in addition to the Umpqua Basin and western and south central Siskiyou County Wednesday afternoon and evening.

Although poor overnight recoveries and breezy east winds return again for the mountains tonight, conditions should improve just enough (mainly slightly weaker winds) to preclude continuing the Red Flag through the overnight hours. Guidance shows only minimal improvement, if any, in wind and humidity today, in addition to much more instability as the thermal trough pushes inland. With today/Thursday being the hottest days, and with continued dry, windy, and unstable conditions, critical fire weather conditions are expected over portions of the area yet again Thursday, including the Rogue, Illinois, and Applegate valleys, where Red Flag conditions are possible each day this week.

We may see some slight cooling and slight improvement to overall winds and humidities beginning Friday, but it may not be enough to bring sections of the area out of Red Flag concerns. This will be further assessed in the coming days.

Outside of the Red Flag Warning areas, for the rest of this week conditions will still be hot, dry, windy, and unstable, with poor ridgetop and east side recoveries, and periods of near-critical conditions.

Looking ahead into the extended forecast, there are signs that a weak dry frontal passage is possible sometime early next week. This could result in slightly cooler to near normal temperatures, but would also bring a period of increased winds, which would heighten fire weather concerns yet again.

MFR WATCHES/WARNINGS/ADVISORIES

OR...Heat Advisory until 11 PM PDT Thursday for ORZ023-024-026- 028>031.

Red Flag Warning from 2 PM this afternoon to 9 PM PDT this evening for ORZ616-617-620>623.

CA...Heat Advisory until 11 PM PDT Thursday for CAZ080-081-083>085.

Red Flag Warning from 2 PM this afternoon to 9 PM PDT this evening for CAZ280-282.

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 AM PDT this morning for PZZ350-356-370-376.