* WHAT...For the Heat Advisory, temperatures up to 95. For the Extreme Heat Warning, dangerously hot conditions with temperatures up to 102 expected.

* WHERE...Catalina and Santa Barbara Islands, Los Angeles County Beaches, Los Angeles County Inland Coast including Downtown Los Angeles, Malibu Coast, Palos Verdes Hills, Santa Barbara County Southeastern Coast, Santa Barbara County Southwestern Coast, Ventura County Beaches, and Ventura County Inland Coast.

* WHEN...For the Heat Advisory, until 10 AM PDT Tuesday. For the Extreme Heat Warning, from 10 AM Tuesday to 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during extreme heat events. Hot temperatures may cause heat illnesses.

...RED FLAG WARNING IN EFFECT 10 AM TUESDAY TO 3 PM FRIDAY FOR MANY INTERIOR PORTIONS OF SOUTHWEST CALIFORNIA DUE TO EXTREME HEAT AND INSTABILITY ALONG WITH LOCALLY GUSTY WINDS AND LOW HUMIDITIES... .A very hot and unstable air mass combined with locally gusty winds and low humidities will bring a significant risk of large plume dominated fires with rapid spread and extreme fire behavior. The National Weather Service in Los Angeles/Oxnard has issued a Red Flag Warning for extreme heat and instability along with locally gusty winds and low humidities, which is in effect from 10 AM Tuesday to 3 PM PDT Friday.

* TEMPERATURES...Highs 98 to 108 across the lower mountains and adjacent foothills, and Cuyama Valley, and 85 to 95 across higher mountains. Lows in the mid 70s to mid 80s common in the mountains and foothills.

* INSTABILITY...Very deep mixing heights of 12,000 to 20,000 feet Tuesday through Thursday, slightly lower on Friday.

* WINDS...Local northwest to north winds 15 to 25 mph with gusts up to 35 mph at times, strongest across the I-5 and Highway 33 corridors. A slightly stronger northerly wind push is possible late Thursday night into Friday morning, with gusts up to 40 mph possible across the I-5 corridor.

* RELATIVE HUMIDITY...Minimum humidities 10 to 20 percent each day, with isolated values as low as 8 percent by Thursday and Friday. Poor recoveries overnight hours in the mountains and foothills with humidities in the 15 to 30 percent range.

* IMPACTS...There is a significant risk of large plume dominated fires with rapid fire spread and extreme fire behavior. There is a history of large plume dominated fires this time of year with similar weather and fuel conditions, including the Bridge, Bobcat, and Station fires.