* WHAT. For the Heat Advisory, temperatures of 93 to 103 degrees expected. For the Excessive Heat Watch, dangerously hot conditions with temperatures of 98 to 108 possible. Warm overnight conditions are expected much of this week, limiting nighttime relief from the heat. * WHERE. Calabasas and Agoura Hills, Central Ventura County Valleys, Ojai Valley, Santa Clarita Valley, Santa Susana Mountains, and Western San Fernando Valley. * WHEN. For the Heat Advisory, from 10 AM this morning to 10 AM PDT Tuesday. For the Excessive Heat Watch, from Tuesday morning through Thursday evening. * IMPACTS. Heat related illnesses increase significantly during extreme heat events.

Mariners should be prepared for abrupt visibility changes down to one nautical mile or less. Reduce speeds and be on the lookout for exposed rocks and other vessels, including large ships in the shipping lanes. Use radar or GPS navigation if available, and consider remaining in harbor if such equipment is unavailable.

AIR QUALITY ALERT DUE TO ELEVATED OZONE AIR POLLUTION. The South Coast AQMD has extended an air quality alert due to high levels of ozone (smog). The air quality alert is in effect until 7 PM Wednesday. Elevated levels of ozone the predominant summertime pollutant are likely to result in poor air quality in the afternoon and early- evening hours. Ozone air pollution can cause respiratory health problems, including trouble breathing, asthma attacks, and lung damage. Children, older adults, and people with asthma or COPD may be more sensitive to the health effects of ozone. Air quality can change depending on time of day and weather conditions. Increased emissions of chemicals and faster ozone formation rates due to heat, along with low winds and stagnant weather can cause unusually high and persistent levels of ozone pollution. To help minimize ozone air pollution levels: - Limit the use of gasoline powered lawn and garden equipment until evening hours - Conserve electricity and set your air conditioner at a higher temperature - Try to delay trips to the gas station and the use of household chemicals until the evening Check air quality levels and take appropriate action as needed. When air quality index (AQI) levels are Unhealthy for Sensitive Groups (orange), people with heart or lung disease, pregnant women, children, and older adults should limit prolonged or heavy outdoor exertion. When air quality reaches Unhealthy (red) AQI levels, everyone may experience adverse health effects and sensitive groups should avoid prolonged time outdoors. At Very Unhealthy (purple) AQI levels, sensitive groups should avoid all outdoor physical activity and everyone else should avoid prolonged or heavy outdoor exertion. To view current and forecasted air quality levels, visit the South Coast Air Quality Management District website at aqmd.gov or download the mobile app at www.aqmd.gov/mobileapp. Additional details for this air quality alert may be available at www.aqmd.gov/advisory. To view current and forecasted air quality levels, visit the Mojave Desert Air Quality Management District website at mdaqmd.ca.gov. Additional details for this air quality alert may be available at www.mdaqmd.ca.gov/advisories. To view current and forecasted air quality levels, visit the Antelope Valley Air Quality Management District website at www.avaqmd.ca.gov. To view current and forecasted air quality levels, visit the San Diego County Air Pollution Control District website at www.sdapcd.org/content/sdapcd/air-quality.html. Additional details for this air quality alert may be available at www.sdapcd.org/content/sdapcd/air-quality/smoke-advisory.html