Next Blast Of Heat For The Bay Area Arrives Friday

SAN FRANCISCO — A new heat advisory will take effect Friday morning for portions of the inland Bay Area, but forecasters expect the latest heat wave will be shorter and less intense. However, the usual hot spots will still land close to triple digits, and most areas outside of downtown San Francisco will see at least minor heat-related risks.

According to the National Weather Service, Friday and Saturday will be the hottest timeframe, when inland portions of Napa, Monterey and San Benito counties will see afternoon highs ranging from 105 to 108 degrees. The East Bay hills, South Bay, northern Sonoma County, and southern Salinas Valley all have highs forecast in at least the upper 90s.

As The Mercury News reports, forecasters say the NorCal warm-up is courtesy of a "gigantic high-pressure bubble" that has settled over the Pacific Southwest — the same culprit that has kept Phoenix afternoons at a blistering 110 degrees for three consecutive weeks.

While the local impacts are less dramatic, even areas near the coast will get a little taste of the heat, and San Francisco should climb toward the mid-70s Saturday.

"Closer to the bays and coast temperatures will become a little warmer than normal for late July, however, a robust maritime cooling influence will remain," NWS Bay Area forecasters wrote Thursday. "Northerly, downsloping winds and a compressed marine layer will keep the North Bay warmest to hottest [the] longest over the weekend."

While places like Brentwood and Livermore will again see triple digits, the cooling influence should help keep things milder for most, with San Jose unlikely to reach 90 and the Peninsula topping out in the low 80s.

Moderate heat risks are forecast for inland portions of the North Bay, East Bay, South Bay and Monterey and San Benito counties, with minor risks for San Mateo and Santa Cruz counties and little impact for San Francisco proper.

Fire hazards are another big concern, with very low relative humidity forecast in the hottest areas.

"Humidity recoveries at night are not expected to be as good due to [the] compressed marine layer," forecasters noted in a Wednesday briefing. "Dry conditions mean fire danger risk is elevated, especially given heavy fuel loading at high elevations."

Fortunately, the burst of heat should be short, and next week's forecast calls for more typical late July temperatures returning across the Bay Area, including its most inland areas