Napans can expect a summery temperature spike on Friday and Saturday, but forecasters expect the hot spell to break as early as Sunday.
Daytime highs at Napa State Hospital are expected to reach 94 degrees on Friday and 91 on Saturday, according to Rick Canepa, a meteorologist at the National Weather Service’s Monterey bureau. Upvalley and Lake Berryessa temperatures will be hotter yet.
Friday’s peak would exceed Napa’s hottest temperture thus far in 2013, a high of 92 reached on May 4 and June 1-2, Canepa said.
Both Napa highs are well above Weather.com’s listed averages of 80 degrees for the two days, though they fall short of the Napa heat records of 99 on June 7 and 102 on June 8, both set in 1973.
The weather service has issued a special weather statement for much of the Bay Area and Central Valley for Friday and Saturday. Farther inland, the agency predicts peaks between 95 and 105, with a few locations approaching daytime highs of 110.
Thursday afternoon, the Bay Area Air Quality Management District announced a Spare the Air alert for Friday, citing unhealthy levels of ozone due to the expected heat as well as light winds and high levels of motor vehicle exhaust. High levels of ozone can cause throat irritation, chest pains and asthma attacks, as well as worsening bronchitis and emphysema symptoms.
Outdoor work and exercise should be moved away from afternoon hours to lessen the risk of heat stress, and pets should be provided plenty of water and either sheltered or moved indoors, the weather service said in a statement.
While swimming is a popular relief from summer heat, Napa’s city Parks and Recreation Department cannot move up its summer swimming program from the scheduled opening day of June 17, according to Stacie Leach, the department’s aquatics coordinator. The program uses two pools owned by the Napa Valley Unified School District, at Napa High School and Redwood Middle School.
“There’s a lot of planning and prep work involved, and it’s not something we can do at the last minute,” she said. “We have to have staff and lifeguards available, so (rescheduling) is something that would need to be planned out. Of course it would be nice to open early, but we have to prepare and make sure the safety of our patrons is the best.”
When the hot weather subsides remained in question as of Thursday. Napa’s high temperature Sunday is forecast to fall sharply to 80 — or 21 degrees below the record June 9 temperature of 101, recorded in 1990 — but the weather service is leaving open the possibility of higher temperatures lingering in the North Bay deeper into the weekend, according to Canepa, the agency forecaster.
As of Thursday afternoon, CalFire had not announced any special weekend restrictions for Napa County. But Suzie Blankenship, spokeswoman for CalFire’s Sonoma-Lake-Napa division, urged residents to reschedule open burning this weekend and pay greater attention to keeping combustible materials at least 100 feet away from buildings and other structures.
“With these high temperatures, we’d encourage people not to be burning at all,” she said. “Even if they have permits, if they can just hold off, there will be a better day for burning rather than this weekend.”
Those holding burn permits between May 1 and the end of the fire season, which can fall between October and December, must first have their burn piles inspected by their local firefighting agency.
CalFire’s 21 stations in Sonoma-Lake-Napa are ahead of schedule in reaching their full staffing of firefighters, which is expected on July 1, Blankenship said.