Northern California is experiencing a heatwave with triple-digit temperatures expected to persist through early next week, driven by a high-pressure system expanding across the state. The National Weather Service in Sacramento forecasts temperatures up to 15 degrees higher than the previous day in parts of the Bay Area and the Sacramento Valley. Heat advisories are in effect for regions including the Western San Fernando Valley, Western and Eastern Santa Monica Mountains Recreation Areas in Los Angeles, as well as western Nevada areas such as Reno-Carson-Minden and Surprise Valley in California. Residents are advised to avoid strenuous outdoor activities and stay hydrated. Concurrently, wildfire smoke from growing fires in northern California and southern Oregon is drifting into northern Nevada and northeastern California, impacting air quality from San Francisco to Sacramento and Redding. Satellite imagery confirms the slow northerly flow aloft is carrying smoke into these regions, prompting warnings to check local air quality levels.