textproduct: Medford

KEY MESSAGES

* Today: Chance (15-20%) for showers and thunderstorms over far eastern Modoc County and far southeast Lake County with lightning being the main threat.

* Temperatures are generally seasonable through Monday, except cooler/slightly below normal temperatures on Saturday.

* A low pressure system next week may bring rainfall and cooler temperatures. Rainfall chances increasing midweek and continuing through later parts of next week, especially for coastal and westside areas.

DISCUSSION

Today, an upper level jet is located over the region with a closed upper level low centered to the northwest over British Columbia and an area of high pressure centered to the southeast over the Desert Southwest. With moisture advecting into southeast portions of the area, a few showers and thunderstorms may develop late today during peak heating when convective temperatures will be reached. Although precipitable water has increased, we not expecting a lot of rain with any showers or thunderstorms that develop. So, the main threat will be lightning along with a potential for isolated gusty winds. The better chances for storms will remain east and southeast of our area.

On Saturday, the low moves over the Pacific Northwest, bringing cooler conditions with slightly below normal high temperatures. Dry weather is expected, with precipitation remaining well to the east.

On Sunday, the upper trough will shift eastward and expect a zonal pattern over the area. This pattern will result in near normal temperatures.

An trough pattern is expected to develop just off the coast on Monday. Then a stronger low is forecast to move down from the Gulf of Alaska and into the region Wednesday into Thursday. There is some uncertainty in the ensembles with the timing, orientation and strength of this system. Overall, the pattern favors troughing with cooler temperatures and increased rainfall chances, especially from the Cascades west. There is significant variability in ensemble solutions on the amount of rainfall. So, we will continue to monitor this for the potential of light/moderate rain. Instability is weak so there are only low chances for thunderstorms but given the variability in the forecast, there is potential for this to change. Continue to monitor the forecast for the latest changes.

AVIATION...28/12Z TAFs

IFR/LIFR stratus and fog will impact most all the coast and into coastal valleys this morning. Then, conditions improve to VFR late this morning and early this afternoon before lowering again in the evening.

Areas of MVFR ceilings have developed in the central and southern Umpqua Basin, around Roseburg and southward, with clearing to VFR expected in late morning and early afternoon.

Patchy clouds could develop in parts of the Illinois Valley or near Grants Pass, but it should remain VFR in Medford. VFR will prevail for all other areas.

Coastal areas will have gusty N breezes (~20-25 kt) this afternoon/evening, while areas east of the Cascades and in NE California have gusty S-SW afternoon winds (20-30 kt). Isolated showers/thunderstorms could graze far SE sections of the area this afternoon/evening, especially out around the Warner Mtns of Modoc/southeastern Lake counties.

MARINE...Updated 100 AM PDT Friday, August 28, 2026

Relatively calm conditions with light north winds and low seas are expected through this morning. North winds increase this afternoon with steep seas developing south of Cape Blanco. These steep seas and gusty winds will persist through the weekend. Winds will be strongest each afternoon and early evening Friday through Sunday. Conditions are likely to improve Monday afternoon.

FIRE WEATHER

Updated 200 AM PDT Friday, August 28, 2026...Aside from a brief period of zonal flow with slight warming and drying on Sunday, upper level troughing will dominate the weather through the forecast period. This will maintain gusty afternoon/evening winds, though generally weaker than yesterday/recent days. Additionally, RHs will trend higher as temperatures continue trending cooler, which will limit critical fire weather conditions.

Meanwhile, onshore flow will generally maintain moderate to good recoveries with nightly marine pushes for coastal zones.

A slight chance of thunderstorms remains in the forecast today for southeast portions of the area, mainly far southeastern FWZ 625 and far eastern FWZ 285. Models continue to show an area of remnant tropical moisture moving into northeast/central CA and northwest NV, which is expected to clip the southeastern portions of the area and some showers and low chances (15-20%) for isolated thunderstorms this afternoon/evening. The better instability and increased chances for thunderstorms will remain south and east of the area. Drier air in the mid- levels returns Saturday and thunderstorms shift eastward.

A stronger trough arrives next week, bringing cooler/below normal temperatures, higher humidities and the potential for rainfall. The best chances for rainfall will be along the coast and from the Cascades west. Instability is week and there are low chances (5-10%) for thunderstorms during this period. However, there remains variability in the models on the forecast for this period. So will continue to monitor this period for changes.

MFR WATCHES/WARNINGS/ADVISORIES

OR...CA...None.

PACIFIC COASTAL WATERS...Small Craft Advisory from 2 PM this afternoon to 5 AM PDT Monday for PZZ356-376.