Medford, Oregon — Warm and dry conditions will give way to a surge of rain and thunderstorms across southern Oregon late Sunday, with downpours expected to create slick roads and rapid water buildup from 2 p.m. to 8 p.m. in Medford, Ashland, and Grants Pass. Drivers could encounter pooling water in low-lying areas and reduced visibility during heavier bursts.
According to the National Weather Service in Medford, a low-pressure system will move south along the coast Sunday into Monday, increasing shower and thunderstorm coverage across the Cascades, Siskiyou County, and inland valleys, with peak activity Sunday afternoon through Sunday night.
Rainfall may overwhelm drainage in rural valleys and flood-prone intersections, especially along I-5 between Ashland and Medford and on smaller roads near the Rogue Valley. Lightning could disrupt outdoor activities, while brief heavier cells may produce small hail and sudden visibility drops. Western Siskiyou County and east-side locations face the highest thunderstorm risk during the late afternoon.
This is part of a broader system shifting inland from the Pacific, adding moisture and instability after a stretch of warm weather.
Avoid travel during heavier storms, do not drive through water-covered roads, and move indoors if lightning develops.
The most dangerous window is 3 p.m. to 8 p.m. Sunday, when thunderstorms and heavy rain peak across southern Oregon.
