textproduct: Medford

DISCUSSION

SPC CAM paintballs currently show thunderstorms developing in Modoc and Siskiyou counties as well as in southern Lake County this afternoon. Radar imagery is starting to match up with that forecast, with the first cells developing in southern Lake County. Thunderstorm development is supported by weak upper air instability and ~500 J/Kg CAPE values, neither of which indicates chances of severe activity. Any isolated activity that develops this afternoon may continue into the evening but would ease into the nighttime.

An upper ridge looks to be in control for Sunday through Tuesday, bringing a warming trend across the area. On Monday and Tuesday, coastal cities are forecast to be in the low to mid 70s. West side valleys look to be in the mid 90s to low 100s, with high 80s to low 90s to the east. In between, higher elevations of the Cascades have high 60s to mid 70s in the forecast. For inland valleys and low- lying areas west of the Cascades, a Heat Advisory has been issued for Monday afternoon through Tuesday night to highlight the hazards that these temperatures present to those who are sensitive to heat or without adequate cooling or hydration. East side valleys and basins may see periods of Advisory-level conditions, so similar awareness is advised even if the criteria for a product was not constantly met.

With the ridge moving eastward and flattening midweek and beyond, a cooling trend is forecast into next weekend. A dry front looks to pass over the area Wednesday, which would bring elevated winds over higher terrain and east of the Cascades. Upper flow with a slight southwest orientation may support a stray thunderstorm or two east of the Cascades on Wednesday afternoon/evening, but this seems like a slight possibility at best in the current forecast. Long-term guidance generally agrees on a second front reaching the coast between Thursday afternoon and Friday morning. This front may bring some light precipitation, although there's disagreement on if that rainfall will be limited to the coast and Cascades or if it will fall across the west side.

Disagreement continues into next weekend. In GFS imagery, zonal to slightly northwest flow would limit additional precipitation and keep temperatures near or just below seasonal norms. The ECMWF deterministic outcome brings a low presure system down over the area, which would bring additional light rainfall across the area on Saturday and Sunday. ECMWF meteograms show good confidence in the low pressure outcome, while the GFS is more divided in its expectations of weekend rainfall. -TAD

AVIATION...20/18Z TAFs

Onshore flow is keeping marine stratus in place along the Oregon coast as well as into the umpqua Valley at the start of the TAF period, with MVFR levels in these areas. A wind change to offshore flow will break this layer up by the afternoon, with a return to onshore flow bringing marine stratus back to North Bend and possibly into the Umpqua Valley later tonight into early Sunday morning.

Inland levels look to remain at VFR through the TAF period, with only normal diurnal winds. Isolated thunderstorms are possible across Siskiyou and Modoc counties this afternoon, but are not expected to reach into Oregon. Any activity that develops this afternoon looks to ease into the evening. -TAD

MARINE...Updated 200 PM PDT Saturday, June 20, 2026

North winds will be at a minimum today, but fresh swell will continue steep seas across most areas. North winds increase this evening and continue to strengthen tomorrow through Monday evening. The result will be strong northerly winds and very steep seas south of Cape Blanco while steep seas remain across most of the northern waters. There may be isolated areas of gale force gusts Sunday afternoon through Monday evening for areas south of Cape Blanco. A pattern of northerly winds is likely to continue through mid-week.

MFR WATCHES/WARNINGS/ADVISORIES

OR...Heat Advisory from 11 AM Monday to 11 PM PDT Tuesday for ORZ023>026.

CA...Heat Advisory from 11 AM Monday to 11 PM PDT Tuesday for CAZ080>082.

PACIFIC COASTAL WATERS...Small Craft Advisory until 2 PM PDT Sunday for PZZ356-370-376.

Hazardous Seas Warning from 2 PM Sunday to 5 AM PDT Tuesday for PZZ356-376.