Autumn Starts Off With Bang : Weather: A thunderstorm blows into the area. A lightning strike cuts power to a hospital and about 2,400 other customers.

Western Ventura County residents were jolted on the first day of fall Monday by booming thunder and a lightning strike that left a hospital and nearly 2,400 homes and businesses temporarily without electricity.

The thunderstorm that blew into the county from Arizona pelted some backcountry areas and parts of the cities of Ventura, Oxnard, Simi Valley and Moorpark with large raindrops for short periods and left other areas bone dry.

Only trace amounts of rain were recorded in most areas, but forecasters predicted more rain in localized areas today, with up to 0.8 of an inch in the county’s mountainous areas before the system subsides Wednesday.

The lightning strike, which hit the ground near Loma Vista Road and Brent Street in Ventura, created a four-inch-wide hole in the street and blew a hubcap off a pickup truck, then bounced to a power transformer, said Kevin Rennie, Ventura City Fire Department engineer.

“It could have killed someone or at least caused severe trauma,” he said. But no one was hurt and emergency generators restored service to critical areas of Community Memorial Hospital, located on the corner where the lightning hit, after only a brief flicker.

Non-essential hospital areas and 2,387 neighboring homes and businesses remained without power for about half an hour, a Southern California Edison representative said.

The thunder and the lightning bolt at 8:37 a.m. drew area residents out to the streets to survey the damage.

“I haven’t heard one like that since Missouri,” said Martha Drive resident Alfred Cecil, who said he left the Midwest 50 years ago.

The weather system, part of Arizona’s typical late-summer storm pattern that was pushed west by warm winds, brought temperatures in the high 90s to the county’s inland valleys and raised readings to near 70 degrees on the coast. Humidity that ranged from 90% to 100% throughout Monday made the heat seem worse, weather officials said.

The warm temperatures drove air quality into the moderate zone throughout most of the county, with only coastal air quality remaining good, said Phil Moyal, air quality specialist with the county Air Pollution Control District.

“The coastal area is nice and clean now,” Moyal said after the morning’s brief rain had washed the air.

Forecasters predict a chance of more thundershowers through today, with the weather system losing strength by Wednesday.

By Thursday the coast and much of the county should again be under the fog that has covered the area all summer.

Next week, however, weather could turn wet again with influences from both Arizona and Mexico, said National Weather Service meteorologist Ted MacKechnie. The winds from the southeast that blew in the front Monday could recur about the time that Hurricane Jimena, which is now 500 miles south of Baja California’s southern tip, moves north into the area.

“A lot could happen before that,” MacKechnie said. “But if the wind-flow pattern holds up . . . things could get very interesting in terms of tropical weather.”