Heat Warnings, Thunderstorm Chances This Week In The Bay Area

SAN FRANCISCO — A three-day blast of heat will send temps toward triple digits in parts of the Bay Area, with heat advisories and excessive heat warnings in place through Wednesday.

While forecasters with the National Weather Service expect inland communities of the East Bay and South Bay to take the brunt of the heat, afternoon highs in the North Bay and on the Peninsula will still run above average.

A heat advisory will be in place for the interior North Bay, South Bay and Santa Cruz Mountains from 11 a.m. Monday to 11 p.m. Wednesday, while an excessive heat warning includes the East Bay hills and valleys, eastern Santa Clara Hills and Santa Lucia Mountains. Communities falling under the latter warning will also contend with unusually warm nights.

"Areas included in the heat advisory will experience well above average temperatures and moderate-to-major HeatRisk," NWS Bay Area warned Monday. "Areas included in the excessive heat warning will see similar or slightly warmer daytime highs, but will struggle to cool below about 70-75 degrees for overnight lows."

Forecasters expect Concord, Livermore and Cloverdale will run hottest, with highs at or above 100 degrees, while struggling to dip below 70 degrees at night. Other potential hot spots include San Jose, Santa Rosa and Napa.

Forecasters are keeping a close eye on the possibility of dry thunderstorms developing, which could add significant fire hazards toward the end of the heat wave.

"There is also a low chance of dry thunderstorms late Tuesday going into Wednesday across much of the area," forecasters said in a Monday briefing. "Monsoonal moisture from the south will be moving in as well as some elevated instability. However, there are some limiting factors to how much of the instability can be realized, so we are keeping the chance to 'low, but non-zero' for now."

Some welcome relief from the heat is due Thursday, kicking off a cooling trend that should last through next weekend. Early forecasts suggest afternoon highs could fall below average by Saturday.