Even as summer presented itself on the first day of the season with a furnace blast around the Bay Area, weather forecasters were keeping an eye on a farther south system that poses a threat to another danger: Dry lightning.
The National Weather Service meteorologist Roger Gass said Tuesday.
“As it does, a lot of rainfall that (the system) could create will go away before it hits the ground,” he said. “That could create lightning with no rainfall associated with it. I wouldn’t call it an electrical storm, but I would call it a possibility of isolated strikes. We are watching it. ”
Your lightning caused a series of fires that grew into a large Bay Area wildfire complex in 2020 and sparked red-flag fire warnings again in 2021.
The high pressure had an obvious effect Tuesday as the mass of hot air sent temperatures soaring toward triple digits in the Bay Area’s off east bay interior, the Santa Clara Valley, and the North Bay. Gass said records were not expected to fall.
The East Bay coastline, the Santa Clara Valley, the Santa Cruz Mountains and the inland areas of Contra Costa, Napa and Sonoma counties.
Concord reached 98 degrees by 1 pm 106. In the South Bay, the temperature was 99 degrees in Hollister at 1 pm and 93 in San Jose. Both cities were expected to reach 99.
“It doesn’t really bother me,” said Manuel Santillan, who lived in Palm Springs before moving back to San Jose about a year and a half ago. He currently does not have an air conditioner.
“It was a lot cooler than it was inside,” he said while shopping at a Whole Foods. “That’s what drove me to come out here, because it was so warm inside my apartment. If you don’t have AC, it’s a lot nicer outside. ”
Napa and Santa Rosa both surpassed 100 degrees by 1 pm and were expected to reach 106 and 104, respectively.
The hot temperatures also contribute to a Spare the Air Alert issued by the Bay Area Air Quality Management District on Tuesday. Residents were advised to avoid traveling.
Wednesday, the Bay Area’s high spots are expected to be 96 degrees – in part because of that lower pressure. According to Gass, the lower pressure is expected to draw in the upper atmosphere of northern New Mexico.
Thunderstorm conditions in the atmosphere above 15,000 feet, Gass said. At the same time, any rain it generates is likely to evaporate before it ever reaches the ground, he said.
“That could create lightning with no rain associated with the rain,” Gass said. “It’s a very difficult thing to forecast where and when that might be. Even if the rainfall hits the surface, it’s usually disconnected to where the lightning actually strikes. ”
The better news for the Bay Area region is that it remains uncertain – if it happens – will make it far far north. Gass said dry lightning was most likely in the southern Sierra Nevada. Climate expert Daniel Swain via social media said the system is expected to cut through Central California but the potential for thunderstorms is decreasing.
“The chances of them developing at this point are probably only about 10-15%,” Gass said. “But obviously, we’re watching it very much, because those thunderstorms and lightning without rain can have a high impact.”
Lightning caused approximately 650 wildfires that burned at least 1.5 million acres across Northern California in August 2020.
The high temperatures are expected to linger for a few days, cooling by a few degrees Wednesday before dipping even further by the end of the week. Places including San Jose and inland parts of the East Bay could see temperatures in the 90s through Friday. By next Tuesday, areas such as Concord, Livermore and the Santa Clara Valley may be back into the 80s.
Cooling centers were open for those seeking reprieve from the heat in Santa Clara and Contra Costa counties.
The US Drought Monitor report, issued Thursday, showed that 97% of California and the entire Bay Area is in a severe state of drought or worse. Sixty percent of the state is mired in extreme drought and 12% was in exceptional drought.
Tuesday’s weather didn’t bring a critical fire threat, because winds weren’t real strong, Gass said. The fire concern was greatest across the North Bay hills, where the winds were the breeziest. As of 1 pm, there hasn’t been any major wild fires Tuesday in the North Bay.
“It’s very dry out there,” Gass said. “You can see all the vegetation has dried up as it usually does this time of year. This air mass is very dry as well. We’re not expecting a significant threat across the Bay Area but you don’t want a spark to start a fire. People need to be thinking about any kind of outdoor activities – it doesn’t take much to start in these kind of conditions. ”