textproduct: Medford

DISCUSSION

A marine stratus layer covers sections of the coast with some mid and high clouds moving over the forecast area this morning. Today will be an interesting day with regards to synoptic weather across southern Oregon and northern California.

A low off the Oregon coast will take on a negative tilt later this evening, providing some extra dynamics for convection and strong winds across the forecast region. It will be a breezy day with sustained winds 10 to 20 mph with gusts up to 35 mph east of the Cascades this afternoon and evening. It looks like the stronger winds aloft around 9000 feet show up late in the evening and overnight hours when we're not mixing, so we'll avoid the really strong winds.

In any case, there is an elevated fire weather risk east of the Cascades in Lake and Modoc counties as winds and humidities in the lower teens combine for a few hours. The hot dry wind index is above the 95th percentile for this time of year with values around 200 to 300, which isn't bad during fire season, yet unusually high for this time of year.

Thunderstorms are another concern, specifically along the Cascade crest. the GFS forecast soundings show uncapped CAPE around 800 J/kg later this evening with 0-6km shear around 50 knots along the Cascade crest, which is rather healthy. It looks like the high resolution models are most ambitious with convection to our north, although we wouldn't be surprised with a few thunderstorms firing near Crater Lake this afternoon. The SPC HREF lightning probability is around 10% for that area, so odds aren't that good.

Eventually, this low and a cold front will push onshore during the overnight hours. The precipitation mode along this front will just be showers and thunderstorms are not expected along the coast overnight. Many would consider this beneficial rain with a few tenths falling along the coast with a few hundreths farther inland up to the Cascades.

Once the cold front moves through, temperatures will trend notably lower by 10 to 15 degrees compared to Tuesday. This will push us to more normal Spring weather with a brief warm up into the 80's on Thursday before we cool again on Friday. By Saturday, models are bringing another low and cold front, although precipitation will be very light over our area. The best chances for rain will be to the north in northern Oregon. There is pretty good consensus that we dry out after Saturday with temperatures warming into the 80's here in Medford next week.

-Smith

AVIATION...12/06Z TAFs

VFR prevails over inland areas late this evening, but as expected, IFR stratus and/or fog has already redeveloped along the coast. The lower clouds/fog will continue to fill in to most locations about 5-10 miles inland overnight into Tuesday morning, but a bit farther inland (10-20 miles) into the Coquille Valley near Coquille and Myrtle Point. VFR prevails elsewhere inland overnight into Tuesday morning (including Roseburg).

Stratus/fog should lift/break up a bit at the coast Tuesday afternoon, but since the flow will be more onshore, could see some persistent cloudy areas. Southerly flow over inland areas and some instability late Tuesday afternoon/evening could lead to iso/sct showers (even a thunderstorm?) in some spots from western Siskiyou County up across the Siskiyous to the Cascades (thunder probability is about 10-20% in these areas). With decent mid-level flow anything that gets going could drift over the valleys (mostly Jackson/eastern Douglas), but as far west as Illinois Valley, Grants Pass and even perhaps Roseburg during the evening. Expect gusty southerly afternoon breezes in NorCal (esp. the Shasta Valley), but also in Oregon east of the Cascades as well as near any shower/tstm that develops.

Tuesday night, an upper trough will move onshore with more widespread MVFR clouds and coastal showers spreading inland by Wednesday morning. The showers could reach northern Klamath and Lake counties Wednesday morning, but areas south and east of the mountains will largely remain dry with VFR. Things mostly dry out with a much cooler air mass Wednesday afternoon. -Spilde

MARINE...Updated 815 PM PDT Monday, May 11, 2026

Gusty northerly winds and steep seas are easing, and seas fall below advisory levels before midnight.

An approaching compact low will bring showers Tuesday night into early Wednesday. There will be an increase in westerly winds and swell Wednesday. Thunderstorms are not expected and seas are forecast to remain below Advisory levels. Northerly winds south of Cape Blanco increase on Thursday and may build steep seas on Friday. -TAD/Hermansen

MFR WATCHES/WARNINGS/ADVISORIES

OR...None.

CA...None.

PACIFIC COASTAL WATERS...None.