Monsoon could bring showers, lightning and high humidity to all of San Diego County on Monday

(Kucher Serhii/serkucher -

Lots of moisture from northwest Mexico and southern Arizona will flow into the region starting on Sunday, lifting the dew point to about 70, which will make the air feel tropical, the weather service said.


San Diego County could get hit by isolated thunder and lightning on Monday and possibly heavy downpours as warm moisture from northern Mexico and southern Arizona flow into the region, the National Weather Service said.

The monsoon also will raise the dew point to 70 or above in some areas, making the air feel sub-tropical.

Such conditions are common this time of year. But the monsoon rarely sparks lightning in downtown San Diego. Forecasters say there’s a 40 percent chance that the city will be hit by a thunderstorm cell on Monday. It’s more likely that lightning will flash across inland valleys and foothills, possibly hitting the ground in places like Ramona and Julian. Lightning also is expected in the mountains, which could receive an inch or more of rain.

Forecasters advise the public to immediately seek shelter if they see or hear lightning. The air surrounding a lightning bolt can reach 50,000 degrees. About 30 people die nationwide each year from being hit by lightning.

The temperature is expected to hit 78 Monday in San Diego, 85 in Alpine, 89 in Valley Center, and 91 in Ramona.

People traveling to Phoenix on Monday can expect a daytime high of 106, as well as thunderstorms. Las Vegas will be 104 and mostly sunny. Palm Springs will be 105 and mostly sunny.