A heat wave is expected to linger in the Bay Area through Thursday night before it cools Friday, according to the National Weather Service.
Temperatures are expected to be well above average on Thursday though highs will be a few degrees lower than Wednesday. A heat advisory has been issued for interior areas, forecasters said.
Overnight lows will range from the upper 50s to mid-60s, which may limit the amount of typical overnight relief from the heat, the weather service said.
A weather system expected in the region Friday into Saturday is expected to bring lower temperatures Friday and into the weekend. But thunderstorms are also possible as that system crosses the region, weather officials said.
Lightning strikes without any rain are possible Friday night while any thunderstorms Saturday will likely include rain.
Spare the Air alerts issued
Soaring temperatures and more cars on the roads brought haze back to Bay Area skies this week, prompting air district officials to forecast unhealthy air for earlier this week.
The district's Spare the Air Alert for Monday was the first of 2020 and Tuesday's air quality isn't going to be any better, according to the Bay Area Air Quality Management District.
Light winds combined with triple-digit inland temperatures along with vehicle exhaust are expected to produce smog, or ozone, accumulation.
"As temperatures and traffic increase in the Bay Area, unfortunately, so does unhealthy air quality," said Jack Broadbent, executive officer of the air district. "When it matters most, we can protect our respiratory health and reduce our exposure to smog by avoiding outdoor activities during the hottest part of the day."
Smog can cause throat irritation, congestion, chest pain, trigger asthma, inflame the lining of the lungs and worsen bronchitis and emphysema. Long-term exposure to ozone can reduce lung function. Ozone pollution is particularly harmful for young children, seniors and those with respiratory and heart conditions.
When a Spare the Air Alert is issued, outdoor exercise should be done only in the early morning hours when ozone concentrations are lower.
People can find out when a Spare the Air alert is in effect by visiting sparetheair.org, calling 800-HELP-AIR (4357-247), downloading the Spare the Air smartphone app for iPhone or Android devices or connecting with Spare the Air on Facebook, Twitter or YouTube.