A heat advisory for the Diablo Range, Santa Cruz Mountains and Big Sur region has been expanded to the East Bay valleys and North Bay Mountains, National Weather Service officials said Friday.
The advisory is in effect from 8 a.m. Saturday to 9 p.m. Sunday for all five locations where temperatures could reach 105 degrees or more.
Heat sensitive residents are at moderate to high risk of heat-related illnesses and the danger of wildfires will rise with the rising temperatures, according to weather officials.
Cooler temperatures are forecast for early next week.
The hottest temperatures for inland valleys and ridges will be in the North Bay, East Bay, South Bay and in Monterey and Santa Cruz counties.
In the North Bay, interior valleys could reach the low 100s, according to weather officials.
On East Bay ridges temperatures are forecast to reach the 90s.
The inland areas of the South Bay are forecast to reach the 90s while ridges will be near 100. San Jose will open several cooling centers Sunday across the city.
Inland valleys of Monterey and Santa Cruz counties are expected to be in the 90s. The ridges could reach the low 100s.
Coastal temperatures from the North Bay to Monterey Bay will be lower, weather officials said.
Across the San Francisco and Monterey Bay areas, temperatures in the hilly and mountainous regions could stay above 70 degrees during the night and early morning hours.
Weather officials said pets and livestock may require extra care during the heat.
The officials suggest residents drink plenty of fluids, stay in air conditioning and out of the sun and check up on neighbors and relatives.