Rain returns to Fresno, central San Joaquin Valley forecast. Will thunderstorms follow?

Weather in Fresno and the rest of the central San Joaquin Valley will start to turn late Sunday, after five days with high temperatures in the 80s.

By Monday afternoon, it could turn gnarly, with a slight potential for wind gusts up to 40 mph, small hail and thunderstorms.

Rain is expected to move through the Valley after 11 p.m., with total new rainfall amounts from the incoming system forecast to range from one-quarter to one-half inch. Thunderstorms possibly would develop Monday afternoon.

“Usually the best chances are during the peak heating of the day, with the most unstable atmosphere,” said Dan Harty, a meteorologist with the National Weather Service in Hanford.

“Aside from the thunderstorm threat there’s definitely going to be some rain. It’s going to be moving in tonight, after sunset, and then showers throughout the day tomorrow. A half an inch would be a pretty good soaking. That’s pretty good for the Valley, especially.”

One-quarter of an inch of rain would mark a high for the year in Fresno, which has had measurable precipitation just three days in March and four times this year — with a high of 0.11 of an inch March 4, according to Weather Service records.

Fresno last had .50 of an inch of rain or more on Dec. 14, 2021, when there was 1.03 inches.

The threat of lightning and flooding exists with all thunderstorms, and what to do if caught outside is common sense: Go indoors.

But if stuck in an open area, the Centers for Disease Control and Prevention recommends getting away from elevated areas including hills, mountain ridges or peaks; never sheltering under an isolated tree, a cliff or rocky overhang; and getting out of and away from ponds, lakes, and other bodies of water and away from objects that conduct electricity such as barbed wire fences, power lines, or windmills.

Also, stay away from concrete floors or walls – lightning can travel through any metal wires or bars in walls or flooring.

There are precautions indoors, as well, including avoiding contact with water and using electronic equipment or corded telephones during a thunderstorm. Lightning can travel through plumbing and electrical systems. Cordless or cellular phones are safe to use during a storm.

This story was originally published March 27, 2022 at 12:17 PM.