Extreme Heat Warning

* WHAT...Dangerously hot conditions with high temperatures in the upper 90s in the western valleys to around 106 in the inland valleys expected. Low temperatures will be mostly in the 70s.

* WHERE...San Diego County Valleys.

* WHEN...Until 8 PM PDT Friday.

* IMPACTS...Heat related illnesses increase significantly during extreme heat events.

* ADDITIONAL DETAILS...Low temperatures 5 to 10 degrees above normal will limit relief from the heat and will increase the threat of heat-related illness.