* WHAT. High temperatures for the inland valleys in the upper 90s to 105 degrees. Low temperatures in the upper 60s to mid 70s for the far inland valleys near the foothills of the mountains. * WHERE. San Diego County Valleys. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Heat related illnesses increase significantly during extreme heat events. * ADDITIONAL DETAILS. A few degrees of cooling are expected Thursday and Friday, followed by warming for the weekend. Temperatures will remain well above average through early next week.

* WHAT. High temperatures in the upper 90s to 105 degrees. Highs up to 108 degrees expected today. Low temperatures in the upper 60s to upper 70s near the foothills. * WHERE. San Bernardino and Riverside County Valleys-The Inland Empire. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Heat related illnesses increase significantly during extreme heat events. * ADDITIONAL DETAILS. A few degrees of cooling are expected Thursday and Friday, followed by warming for the weekend. Temperatures will remain well above average through early next week.

* WHAT. High temperatures in the 90s to 100 expected. Low temperatures in the mid 60s to lower 70s. * WHERE. San Diego County Mountains. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Hot temperatures may cause heat illnesses. * ADDITIONAL DETAILS. Well above average high and low temperatures are expected through early next week.

* WHAT. Dangerously hot conditions with high temperatures in the mid 90s to 102 expected. Low temperatures in the upper 60s to upper 70s. * WHERE. Santa Ana Mountains and Foothills. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Heat related illnesses increase significantly during extreme heat events. * ADDITIONAL DETAILS. A few degrees of cooling are expected Thursday and Friday, followed by warming for the weekend. Temperatures will remain above average through early next week.

* WHAT. Dangerously hot conditions with temperatures from 107 to 114 degrees. Low temperatures in the mid 70s to upper 80s expected. * WHERE. Coachella Valley and San Diego County Deserts. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Heat related illnesses increase significantly during extreme heat events. Warm overnight temperatures will lead to less relief from the heat, prolonging impacts. * ADDITIONAL DETAILS. Well above average temperatures will continue through early next week

* WHAT. High temperatures in the 90s to 100 degrees below 5000 feet. Low temperatures in the mid 60s to mid 70s below 5000 feet. * WHERE. Riverside County Mountains and San Bernardino County Mountains. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Hot temperatures may cause heat illnesses. * ADDITIONAL DETAILS. Well above average high and low temperatures are expected through early next week.

* WHAT. Dangerously hot conditions with high temperatures from 106 to 114 expected. Low temperatures in the mid 70s to upper 80s. * WHERE. Coachella Valley and San Diego County Deserts. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Heat related illnesses increase significantly during extreme heat events.

* WHAT. High temperatures in the 90s to around 100 below 5000 feet expected. Low temperatures in the mid 60s to mid 70s below 5000 feet. * WHERE. Riverside County Mountains and San Bernardino County Mountains. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Hot temperatures may cause heat illnesses.

* WHAT. High temperatures in the mid 90s to 105 expected. Low temperatures in the upper 60s to upper 70s near the foothills. * WHERE. San Bernardino and Riverside County Valleys-The Inland Empire. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Heat related illnesses increase significantly during extreme heat events.

* WHAT. High temperatures for the inland valleys in the mid 90s to 104 expected. Low temperatures in the upper 60s to mid 70s for the far inland valleys near the foothills of the mountains. * WHERE. San Diego County Valleys. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Heat related illnesses increase significantly during extreme heat events.

* WHAT. Dangerously hot conditions with high temperatures in the mid 90s to 102 expected. Low temperatures in the upper 60s to upper 70s. * WHERE. Santa Ana Mountains and Foothills. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Heat related illnesses increase significantly during extreme heat events.

* WHAT. High temperatures in the upper 80s to upper 90s expected. * WHERE. San Diego County Mountains. * WHEN. Until 8 PM PDT Monday. * IMPACTS. Hot temperatures may cause heat illnesses.

The South Coast AQMD has extended an air quality alert due to increased fine particle pollution from wildfire smoke in the region. The air quality alert is in effect until 5 PM Friday. If you smell smoke or see ash due to a wildfire, remain indoors with windows and doors closed or seek alternative shelter, if feasible. Avoid vigorous physical activity and run your air conditioner and/or an air purifier. If possible, do not use whole house fans or swamp coolers that bring in outside air. Avoid burning wood in your fireplace or firepit and minimize sources of indoor air pollution such as candles, incense, pan-frying, and grilling. If you must be outdoors, keep the time brief and wear a tightly-fitted N-95 or P- 100 respirator to help reduce exposure. Limit the use of gasoline powered lawn and garden equipment. Exposure to particle pollution can cause serious health problems, aggravate lung disease, cause asthma attacks and acute bronchitis, and increase risk of respiratory infections. People with heart or lung diseases should follow their doctor's advice for dealing with episodes of unhealthy air quality. Additionally, people with respiratory or heart disease, older adults, and children are particularly susceptible and should avoid prolonged exposure, strenuous activities or heavy exertion as conditions dictate. Levels of particle pollution can vary hour by hour and by location depending on fire behavior and local weather conditions. 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. For the latest air quality forecasts and information, visit the website at aqmd.gov.