The relentless heat wave baking the Bay Area and Northern California, originally expected to peak on Tuesday of this week, will last into the weekend, forecasters said Friday.

A Red Flag Warning has been issued for parts of several Bay Area counties, according to the National Weather Service. The warning went into effect Friday and will remain in effect until 9 a.m. Saturday.

The National Weather Service issued a red flag warning for parts of the Bay Area that will last through at least Saturday morning due to “critically dry” and windy conditions that could lead to easier fire starts and spreads particularly in areas of grasses and shrubbery,