textproduct: Medford

KEY MESSAGES

* Low chances of thunderstorms in the high central Cascades this afternoon and again on Monday.

* Temperatures trend slightly warmer mid week as high pressure builds.

* An upper level low will move up the coast on Friday with a low chance of showers and thunderstorms across the state of Oregon.

* Seasonal temperatures for most of the week.

DISCUSSION

We're watching more cumulus build ups over the higher Cascades this afternoon as some moisture and upper level energy are present in the atmosphere. We have a 5-10% chance of thunderstorms in the high Cascades near Crater Lake this afternoon. Again, model guidance isn't too ambitious about thunderstorms, although the FV3 model is predicting some echos late this afternoon. Convective available potential energy(CAPE) is modest around 500 J/kg with 20 to 25 knots of shear. It looks like we are missing some stronger lifting mechanisms in this environment, so perhaps thats why thunderstorm coverage isn't higher.

By tonight, the marine stratus will likely make another push into the Umpqua Basin based off data from the REFS. The probability of low clouds is about 60% with low stratus and fog continuing to cover the Oregon coast.

Moving further into Monday, some upper level energy will shoot up into Oregon with the low chances(~5%) for thunderstorms continuing around Crater Lake and northern Klamath County with similar 500-750 j/kg CAPE values. Again, the upper air pattern is messy with 500 mb vorticity and a broad and shallow short wave riding over the ridge just to the east. If storms do form, they'll be isolated and fairly brief based on guidance from the convective allowing models.

Heading into the remainder of the week, The ridge begins to build into Oregon and California with heights rising slightly, although a cut off low remains out over the Pacific off the central California coastline. Historically, these lows will give us a chance at thunderstorms around northern California, however that isn't the case this week. The national blend of models is keeping us very dry through the middle of the week. About 3 out of the 50 ECMWF ensemble members are predicting convection around the Wednesday and Thursday timeframe, so just a small chance.

The best chances for precipitation arrive on Friday when the low off the California coast moves northwards providing deeper lift over our area. The NBM has a 20% chance of precipitation over the Cascades Crest at this time. However, the 12Z ECMWF ensemble is not as ambitious with shower and thunderstorm activity during Friday. In fact, it looks like things have trended drier based off the latest data.

As this low moves north, the cloud cover and potential cold front will push temperatures lower here in Medford with a high around 88 on Friday and 89 on Saturday. That should be right around normal for the end of August.

Overall, thunderstorms and showers are the biggest weather feature to watch through the week. Nothing stood out on the extreme forecast index(EFI) product over the next 7 days, so minimal weather impacts for the region.

-Smith

AVIATION

18Z TAFS..Lower ceilings are clearing up this afternoon near KOTH with LIFR ceilings and fog persisting near Brookings. VFR conditions will develop away from the coast this afternoon with the low chance of thunderstorms around the Cascades. We'll see the marine stratus move in again along the coast with LIFR ceilings and some MVFR ceilings farther inland near RBG Sunday night into Monday morning. Visibilities should also be poor along the coast due to fog overnight.

-Smith

MARINE...Updated 330 PM PDT Sunday, August 16, 2026

Gusty north winds will cause steep, hazardous seas south of Cape Blanco tonight through Monday evening. Brief improvement is expected late Monday night or early Tuesday, but advisory level north winds and steep seas will likely redevelop Tuesday afternoon and persist through Wednesday. -Spilde

MFR WATCHES/WARNINGS/ADVISORIES

OR...CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory until 2 AM PDT Tuesday for PZZ356-376.