Fresno, California — Isolated thunderstorms will develop across the Sierra Nevada this weekend, bringing lightning, gusty winds and brief heavy rain that could disrupt travel and outdoor activity Sunday afternoon and evening.
According to the National Weather Service in Hanford, storm chances range from 5 to 15 percent, increasing Sunday with the most active period expected between 2 p.m. and 8 p.m. Thunderstorms may produce sudden wind gusts, small hail and cloud-to-ground lightning across areas including Fresno, Mammoth Lakes, Bishop, Oakhurst and Yosemite Valley.
While rainfall will be brief, heavier bursts can create slick conditions on mountain highways such as CA-120, CA-168 and CA-41, especially near steep terrain and burn scar areas where runoff can develop quickly. Lightning poses the most significant risk, with strikes possible on exposed trails, ridgelines and near campgrounds. Gusty winds may also bring down small branches, creating hazards on narrow mountain roads.
This is part of a broader pattern of increasing instability across the Sierra, supporting isolated convection during peak heating hours.
Visitors and residents should avoid high-elevation exposure during the afternoon, seek shelter immediately when thunder is heard and delay hiking or boating activities.
The greatest risk will occur between 2 p.m. and 8 p.m. Sunday, when lightning and gusty storms are most likely to create sudden hazardous conditions.
