textproduct: Medford

DISCUSSION

Updated aviation discussion for 00Z TAFs.

AVIATION...20/00Z TAFs

Inland, VFR will prevail tonight through Thursday evening. Wildfire smoke is emanating from the Wright's Spring fire and the Mile Post 18 fire. Smoke impacts though should be fairly localized to their immediate vicinity. The main aviation impact will be the marine layer along the coast. Expect low clouds and fog to return to areas north of Cape Blanco, including North Bend in the next hour or so and also near/south of Gold Beach overnight into Thursday morning. This will bring a mix of IFR/LIFR along with patchy drizzle through Thursday morning. Most areas clear to VFR Thursday afternoon, but some lower conditions could linger at the beaches. -Spilde

PREV DISCUSSION

/Issued 201 PM PDT Wed Aug 19 2026/

KEY MESSAGES...

* Dry weather is expected for inland areas through Thursday with above normal warmth and fairly typical afternoon breezes.

* Nightly marine pushes will bring cooler air and stratus to the coast, and also a chance of drizzle.

* Offshore low pressure brings heightened fire weather concerns Friday and Saturday with gusty winds and at least a slight chance of thunderstorms.

* Breezy winds continue Saturday with a slight cool down.

* Typical summer conditions return Sunday and persist into early next week.

DISCUSSION...Typical summer weather is expected for much of the forecast period. Southwesterly flow will persist over the region as the area remains wedged between low pressure over the eastern Pacific and high pressure over the Desert Southwest. The pattern amplifies today into Thursday as low pressure offshore nudges eastward and the flow will turn a bit more southerly Thursday and Friday. As the pattern amplifies, temperatures will trend warmer today and Thursday, with afternoon highs peaking around 5-10 degrees above normal for inland locations. Persistent onshore flow will maintain cooler temperatures along the coast, along with nightly intrusions of the marine layer. Despite the increase in temperatures, overall HeatRisk remains minor with some areas of moderate. These temperatures (mid to upper 90s west side valleys/triple digits in the lower Klamath river valley/upper 80s- low 90s for East side and Umpqua Basin) are fairly typical for this time of year, so just be sure to stay hydrated and take frequent breaks if working during the peak of the heat.

Low pressure offshore will move northeastward into the Pacific Northwest Thursday through the weekend, and this will bring a general cooling trend Friday into Saturday. We'll also see an increase in gusty winds, cloud cover and thunderstorm chances. There will be an increase in afternoon winds on Thursday, but winds are expected to peak on Friday with gusty south to southwest winds across NorCal and from the Cascades eastward and northwest winds in the West Side Valleys. This will lead to elevated fire weather concerns if daytime RHs are low enough, and more details can be found in the Fire Weather Discussion below. Guidance has trended slower with the progression of this trough, so we expect another day of stronger winds to continue into Saturday, focused along and east of the Warner mountains. Aside from cooler temperatures and gusty winds, thunderstorms will be possible with this system. Current guidance still maintains the best chances (isolated/15-25%) will be along the Cascades from Crater Lake northward and across northern Klamath and Lake Counties. There's also lesser chances (5-10%) farther south into western Siskiyou County, but guidance favors the northern areas. The trough just isn't in a favorable position to bring a more widespread thunderstorm threat. It's too far offshore when it's south enough, then to far north when it's near enough. That's not to say thunderstorms aren't likely, just not as concerned about a widespread threat. The other aspect we're monitoring for is the potential for nocturnal lightning. Still think this is a low concern, but the most favorable time period would be Thursday night into Friday morning and over portions of western Siskiyou. While the moisture is there, the forcing and instability are weak, so at this time, it looks like about a 5% chance of an isolated thunderstorm Thursday night. Friday night into Saturday, drier air will have moved into the region, and the threat will have shifted farther north.

Thunderstorms drop out of the forecast on Saturday as the trough finally moves inland near Seattle on Saturday afternoon and drier air moves into the region. Southwest flow persists Sunday into early next week with persistent ridging to the southeast and persistent troughing off the BC coast. Additional shortwaves are likely to pass through the region in this southwest flow, but there are differences on strength and timing. Overall, this will maintain seasonable conditions with temperatures near to slightly above normal (no heatwaves expected) and periods of enhanced afternoon winds. /BR-y

AVIATION...19/18Z TAFs...Aside from lingering stratus south of Gold Beach resulting in LIFR conditions along the immediate the coast, VFR conditions prevail across the region and will do so through the TAF period for most locations. Marine stratus is likely to linger through much of the TAF period for the immediate coast south of Gold Beach, though there could be a brief period VFR conditions later this afternoon. IFR/LIFR conditions in marine stratus will return to areas north of Cape Blanco this evening once gusty north winds ease around sunset, then persist well into Thursday morning. VFR conditions will prevail for all other areas. /BR-y

MARINE...Updated 300 PM PDT Wednesday, August 19, 2026...Gusty north winds and steep seas are expected south of Cape Blanco through this evening. Conditions are expected to improve Thursday and Friday. A thermal trough will redevelop along the coast around Sunday bringing a return of strong north winds and steep seas. Once again, strongest winds and highest seas are most likely south of Cape Blanco.

-Smith

FIRE WEATHER...Updated 200 PM PDT Wednesday, August 19, 2026...Fire weather concerns will remain fairly standard for this time of year today. Expect typical summer conditions with dry weather across the area through Thursday and nightly marine pushes along the coast. Temperatures will trend upward through Thursday, resulting in a downward trend in afternoon RHs. Overall, recoveries will remain in the moderate to good range, though poor to moderate recoveries are expected along and east of the Warners as well as the Salmon Mountains in western Siskiyou County through Friday morning.

Thursday will be a transition day into a pattern that brings some heightened fire weather concerns. A stronger upper level trough, currently spinning out beyond 140 W, will gradually move eastward this week, moving inside of 130 W by Thursday. This will start a period of increased winds that will likely persist through Saturday as this low pressure gradually moves inland into the PacNW through the weekend.

Guidance has slowed the progression of this trough, but also come into better agreement with timing. We still expect an increase in afternoon winds on Thursday with low RHs, but confidence has increased on the strength of the winds not quite reaching critical thresholds on Thursday. Isolated areas of critical conditions are certainly possible on Thursday, but widespread critical conditions aren't expected until Friday. The Shasta Valley could see some critical winds/RH overlap on Thursday, but we don't think it will quite meet the duration requirement. Gusts 15 to 25 mph will be common across the region, with daytime RHs ranging from the low to upper teens and this will result in elevated fire weather conditions on Thursday. Confidence is higher for winds to peak on Friday (gusts 25-35 mph), but daytime humidities will also trend somewhat higher. Despite the uptick in humidities, it's close enough with the higher confidence more widespread higher winds on Friday to warrant a Fire Weather Watch for Friday. This includes Fire Weather Zones (FWZs) 281, 284, 285 and 624. Decided to leave out FWZ 625 at this time as confidence is not high enough for sustained winds to reach criteria on Friday.

In addition to winds/RH concerns for Friday, mid-level moisture increases Thursday and Friday, raising the concern for thunderstorms potential. Current guidance maintains that the best chance for storm development would be along the Cascades from Crater Lake northward and across northern Klamath/Lake Counties. With the approach of the trough Thursday night into Friday, we're monitoring the potential for any nocturnal convection, but current guidance maintains around a 5% chance of that for now, primarily for western Siskiyou County.

Despite the slower progression of the trough, confidence is fairly good that the thunderstorm threat will shift north of the area by Saturday. What changes, however, is the continuation of stronger southwest winds over portions of the East Side/Modoc. While it's likely to be another breezy day, most areas should see weaker winds on Saturday compared to Friday. The strongest winds look to linger along the Warner Mountains and eastward on Saturday, and this is when FWZ 625 stands the best chance of reaching that sustained wind criteria for critical conditions. Additionally, daytime RHs trend downward compared to Friday, so we'll be evaluating the need for additional watches for Saturday.

More typical summer conditions return Sunday and persist into early next week. /BR-y

MFR WATCHES/WARNINGS/ADVISORIES

OR...Fire Weather Watch from Friday afternoon through Friday evening for ORZ624.

CA...Fire Weather Watch from Friday afternoon through Friday evening for CAZ281-284-285.

PACIFIC COASTAL WATERS...Small Craft Advisory until 11 PM PDT this evening for PZZ356-376.