SAN DIEGO -- Heavy humidity and sweltering temperatures that have gripped the San Diego area this week combined Wednesday to generate thunderstorms and downpours from the region's mountains to its beaches.
The bouts of lightning were most intense across the East County but also lit the skies in such coastal locations as Chula Vista, Oceanside and San Diego, according to the National Weather Service, which recorded 396 cloud-to- ground strikes over the day.
The unsettled atmospheric conditions -- courtesy of monsoonal moisture out of Mexico and oppressive late-summer heat -- also included high winds and cloudbursts in much of the county and led to scattered power outages.
Over the 12-hour period ending at 4:30 p.m., the showers dropped 1.17 inches of moisture in Pine Valley; 1.07 in Cameron Corners; 0.55 in Descanso and Echo Dell; 0.49 in Oak Grove; 0.35 on Mount Woodson; 0.34 in Escondido; and 0.23 in Alpine and Flinn Springs.
Other rainfall readings over the period included 0.2 inches in Harbison Canyon; 0.18 in Granite Hills; 0.16 in El Cajon; 0.14 at Brown Field airport and in Rancho Bernardo; 0.12 in Santee; 0.11 in La Mesa; 0.04 at SeaWorld San Diego; 0.03 at Mission Beach; 0.02 in Kearny Mesa; and 0.01 in La Jolla and Lemon Grove.
In the late afternoon, utility crews were working to restore power to areas affected by the weather-related blackouts, which mostly were centered in the eastern reaches of the county, according to San Diego Gas & Electric.
The hot, soupy conditions were expected to continue Thursday prior to a cooling and drying-out trend due to begin at the end of the workweek and continue into Monday, weather service meteorologist Noel Isla said.
In Alpine, a lightning strike possibly sparked a brush fire in the 2100 block of Lyons Valley Road, according to the Alpine Station of San Diego County Sheriff’s Department.
The National Weather Service warned beachgoers in Encinitas clear the city's beaches and take shelter due to a lightning storm near the coast. Beachgoers were told to seek shelter away from the water or metallic umbrellas until 4:30 p.m.