Dog Days Unleashed

Ventura County’s unseasonably cool summer came to an abrupt end this week as the hottest blast of the season teamed with sticky humidity to leave no doubt, especially in valley areas, that the dog days have arrived.

Triple-digit temperatures just shy of record-breakers scorched Simi Valley and Ojai on Thursday. It was 99 in Thousands Oaks. Midday heat has hovered in the mid- to upper 90s for the past week, said Gary Ryan, meteorologist for the National Weather Service in Oxnard.

“This is a heat peak for us, the hottest time of the year for Ventura County,” Ryan said.

Forecasters expect more temperatures around 100 degrees in the inland valleys and around 80 near the beaches once patchy clouds burn off. The heat will press right on through the weekend and possibly into early next week, when many public schools start a new year.

The last time it baked like this was the second week of July, and even then it was a few degrees cooler. It’s always hottest at the end of August and early September because cool onshore breezes fade, offshore Santa Ana winds have not yet started blowing and long summer days continue to pour on sunshine, Ryan said.

Even beach communities, which have been shrouded in early morning fog and mist through much of the summer, got a tinge of summer fever Thursday. It was 83 in Oxnard, 81 in Ventura, and 78 at Point Mugu, up substantially from the mid-70s posted in those communities Wednesday.

Surging humidity added to the misery. Relative humidity hovered around 60% countywide, considerably more sticky than a few days ago. The moisture resulted in panoramic cloud displays and some thunderstorms over mountain ranges.

Forecasters credit the humidity to tropical moisture pulled from Mexico into a pinwheel of low pressure over the Central Valley. The good news is the system will soon begin moving east, which should make the days less sultry.

The heat wave has been awful for 6-year-old Erin Chisholm, who pedaled her pink bicycle past the Ventura Pier, where her Ojai family fled to escape the heat Thursday.

“Oooeee, it’s been so hot!” Erin said, wiping her brow beneath her bike helmet. “I like it here because it’s much cooler.”

“There’s been a steady flow of people all day,” said Karli Youngblood of Ojai Ice Cream. “People are saying they are coming in here because it is really hot outside. We’re selling a lot of ice cream.”

“I kind of like the heat. It’s summer, my favorite time of year,” said 19-year-old Brianne Waschele, who cooled off with a jumbo Diet Coke as she sped off in her Miata in Thousand Oaks.

Oddly enough, the siege of hot weather saved Ventura County air quality, which was sliding into the unhealthful range a week ago.

The season’s first day of unhealthful air was posted in Simi Valley on Sunday, when ozone reached 0.13 parts per million, slightly above the federal health-based limit. The onset of extreme heat obliterated a ground-hugging inversion that was trapping pollutants, allowing smog to disperse.

Clouds and moisture, too, help tame smog, which should remain in the low to moderate range through the weekend, said Kent Field, meteorologist for the Ventura County Air Pollution Control District.