Residual moisture from the remnants of Tropical Cyclone Alberto will move into Southern California and the adjacent coastal waters this weekend. This will bring a slight chance of a few thunderstorms over the local waters this weekend. The chances are currently less than 20 percent at any one location. The most likely timing of this activity will be late Saturday night through Sunday afternoon. Any thunderstorms that develop would be capable of producing dangerous cloud-to-water lightning, gusty winds, small hail, and brief heavy rain. Mariners are encouraged to closely monitor the situation and consider making alternative plans if the chances for thunderstorms were to increase.

* WHAT. Dangerously hot conditions with temperatures 110 to 114 degrees expected. * WHERE. San Diego County Deserts. * WHEN. From 10 AM Saturday to 8 PM PDT Thursday. * IMPACTS. Heat related illnesses increase significantly during extreme heat events. * ADDITIONAL DETAILS. High temperatures on Sunday may be a few degrees cooler than Saturday, but warming conditions return Monday through Thursday.

* WHAT. Temperatures 90 to 98 degrees expected. * WHERE. For elevations below 5000 ft in the Riverside County Mountains, San Bernardino County Mountains, and San Diego County Mountains. * WHEN. From 10 AM to 8 PM PDT Saturday. * IMPACTS. Hot temperatures may cause heat illnesses.

* WHAT. Temperatures 90 to 100 degrees expected. * WHERE. San Diego County Valleys. * WHEN. From 10 AM Saturday to 8 PM PDT Sunday. * IMPACTS. Hot temperatures may cause heat illnesses. * ADDITIONAL DETAILS. Saturday will be the hottest day, but highs in the mid to upper 90s are still expected on Sunday.