UPDATE: Thunderstorms with pea-sized hail Wednesday

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An updated report was issued from the NWS San Francisco CA on Wednesday at 5:47 p.m. for strong thunderstorms until 6:15 p.m. for Santa Cruz Mountains and Santa Clara Valley Including San Jose.

Wind gusts of up to 40 mph and pea-sized hail (0.25 inches) are anticipated.

"At 5:47 p.m., Doppler radar tracked a strong thunderstorm over Campbell, moving southeast at 5 mph," adds the NWS. "Gusty winds could knock down tree limbs and blow around unsecured objects. Minor damage to outdoor objects is possible."

Locations impacted by the alert include San Jose, Campbell, Los Gatos and Cambrian Park.

According to the NWS, "Monitor the weather situation closely and be alert for threatening weather conditions."

This alert is in effect until 6:15 p.m.

Actions to take when lightning threat is imminent

Lightning strikes the United States about 25 million times a year. Most of the strikes occur in the summer, killing 20 people each year, according to the NWS. Chance of lightning increases as a thunderstorm approaches and peaks when the storm is overhead. It diminishes as the storm moves away.

Here are tips on how to stay safe during a thunderstorm:

• To decrease the risk of getting struck by lightning, when you go outside, establish a plan to reach a safer place.
• If the sky grows ominous and you hear thunder, seek out a safe place to take shelter.
• Once indoors, avoid touching corded phones, electrical equipment, plumbing, and windows and doors.
• Wait for 30 minutes after the last lightning or thunder before going back out.

If finding indoor shelter is not an option:

• Avoid open fields, the top of a hill, or a ridge top.
• Keep a distance from tall, solitary trees or other elevated structures. When in a forest, stay in proximity to shorter tree groupings.
• If you are with a group, fan out to stop the current from transmitting between members.
• If you are camping in an open area, set up camp in a valley, ravine, or other low area. Remember, a tent offers no protection from lighting.
• Stay away from water, wet items, and metal objects. Water and metal do not attract lightning but they are excellent conductors of electricity.

What to do in the rain on the road?

• Switch on headlights - Even during daylight hours, using headlights can enhance visibility and signal your presence to other drivers.
• While driving - Stick to the middle lanes and stay on elevated ground. Rainwater tends to accumulate at the road edges.
• Steer clear of puddles - Driving into puddles or low areas of rainwater can cause vehicles to hydroplane or skid out of control.
• Give ample space to large vehicles - Trucks or buses can create a water spray that diminishes visibility.
• Steer clear of flooded areas - When coming to a flooded road, turn around and head back. Flash flooding currents are strong and can sweep drivers off roadways. Driving through deep water can also affect a vehicle's mechanical and electrical systems.

What is hydroplaning?

Hydroplaning occurs when a vehicle begins to slide uncontrollably on wet roads.

This happens when water in front of the tire builds up faster than the vehicle's weight can push water out of the way. The water pressure then causes the vehicle to rise and slide on a thin layer of water between the tires and the road, making the driver lose control. The three main causes of hydroplaning are:

1. Vehicle speed - When a vehicle's speed increases, the tire-traction grip and ability to control the vehicle decreases. Drive at a reduced speed during wet weather.
2. Water depth - The deeper the water, the sooner a vehicle loses traction on the road. It doesn't matter how deep the water is, even a thin layer can lead to hydroplaning.
3. Tire tread depth - Checking your tire tread before hitting the road is important, as low or no tread can lead to sliding.

In the event of your vehicle hydroplaning, here's what to know:

• Ease off the accelerator - Step off the gas to slow down the vehicle until the tires find traction.
• Turn into the skid - Turning into the skid can help the vehicle's tires realign to regain control.
• Make sure the tires reconnect with the road - During the skid, wait until the tires reconnect with the road and then gently straighten the wheels to regain control.
• Brake gently as needed - Brake normally if the vehicle has anti-lock brakes and pump brakes gently if in an older vehicle.

Source: The National Weather Service

United Robots California

This story was originally published May 27, 2026 at 5:24 PM.