The entire Bay Area will be under a heat advisory beginning Monday morning and ending Wednesday night, according to the National Weather Service. Inland temperatures could reach as high as 105 degrees in some places, with coastal highs reaching as high as 93 degrees, weather forecasters say. Even the warmer microclimates in San Francisco should reach the mid to upper 80s on Monday, the weather service said. The heat advisory runs from 11 a.m. Monday through 11 p.m. Wednesday. Onshore winds are expected to return Wednesday afternoon, bringing relief to coastal areas by Thursday, but inland areas are expected to remain hot through Friday, the weather service said. The heat will be such that no one should leave people or pets in vehicles without air conditioning; outdoor activities should be limited for those who are sensitive to heat; and people should stay hydrated.