The extreme heat poses significant risks to outdoor activities, work commutes, and vulnerable populations such as older adults and pets. Heat index values reaching up to 105°F (40.6°C) can lead to heat-related illnesses if precautions are not taken. Dense fog in the mountains on Sunday morning may reduce visibility, creating hazardous driving conditions. Later in the week, isolated thunderstorms could bring localized flooding and lightning risks, especially in the mountains.