Heat Advisory

* WHAT...For the first Extreme Heat Warning, dangerously hot conditions with heat index values up to 109. For the second Extreme Heat Warning, dangerously hot conditions with heat index values up to 107 expected. For the Heat Advisory, heat index values up to 105 expected.

* WHERE...Portions of north central Maryland, northwest Virginia, and eastern and panhandle West Virginia.

* WHEN...For the first Extreme Heat Warning, until 8 PM EDT this evening. For the second Extreme Heat Warning, from 10 AM to 8 PM EDT Friday. For the Heat Advisory, from 10 AM to 8 PM EDT Saturday.

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