* WHAT. Maximum heat index values 100-102 Friday afternoon. Maximum heat index values 102-104. Maximum heat index values 100-103 Sunday afternoon. * WHERE. A portion of central Pennsylvania. * WHEN. Until 8 PM EDT Sunday. * IMPACTS. Hot temperatures and high humidity may cause an increase in heat-related illnesses. * ADDITIONAL DETAILS. The risk of heat-related impacts is expected to reach its highest level over the weekend. The early arrival of the heat in the summer season, persistence of heat over multiple days, and very warm nights will be aggravating factors of overall heat stress.

* WHAT. Heat index values up close to or over 100. * WHERE. A portion of central Pennsylvania. * WHEN. Until 8 PM EDT Sunday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

* WHAT. South winds 10 to 15 kt with gusts up to 20 kt expected. * WHERE. Chesapeake Bay from Pooles Island MD to North Beach MD, Eastern Bay, and Choptank River to Cambridge MD and the Little Choptank River. * WHEN. From 2 PM this afternoon to 2 AM EDT Sunday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. Heat index values between 100 to 105 expected. * WHERE. Portions of north central and western Maryland, northwest and western Virginia and eastern and panhandle West Virginia. * WHEN. From 11 AM to 8 PM EDT today. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses to occur. * ADDITIONAL DETAILS. Oppressive heat and humidity will overspread the area today and last into Sunday. Little relief from the heat is expected tonight with low temperatures in the mid 70s to near 80 for most, which will compound heat stress on those without air conditioning.

* WHAT. Heat index values between 105 to 110 expected. * WHERE. Portions of central, north central, northeast, northern and southern Maryland, The District of Columbia and central, northern and northwest Virginia. * WHEN. From 11 AM to 8 PM EDT today. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses to occur. * ADDITIONAL DETAILS. Oppressive heat and humidity will overspread the area today and last into Sunday. Little relief from the heat is expected tonight with low temperatures in the mid 70s to near 80 for most, which will compound heat stress on those without air conditioning.

* WHAT. Heat index values up to 104 expected. * WHERE. Portions of north central and western Maryland, northwest and western Virginia and eastern West Virginia. * WHEN. From 11 AM this morning to 8 PM EDT this evening. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses to occur. * ADDITIONAL DETAILS. Oppressive heat and humidity will overspread the area today and last into Sunday. Little relief from the heat is expected tonight with low temperatures in the lower to mid 70s, which will compound heat stress on those without air conditioning.

* WHAT. Heat index values up to 108 expected. * WHERE. Portions of central,northeast, and southern Maryland, The District of Columbia, and central and northern Virginia. * WHEN. From 11 AM this morning to 8 PM EDT this evening. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses to occur. * ADDITIONAL DETAILS. Oppressive heat and humidity will overspread the area today and last into Sunday. Little relief from the heat is expected tonight with low temperatures in the mid 70s to lower 80s, which will compound heat stress on those without air conditioning.

* WHAT. South winds 10 to 15 kt with gusts up to 20 kt expected. * WHERE. Chesapeake Bay from Pooles Island MD to North Beach MD, Patapsco River including Baltimore Harbor, Chester River to Queenstown MD, Eastern Bay, Choptank River to Cambridge MD and the Little Choptank River, and Patuxent River to Broomes Island MD. * WHEN. From 2 PM this afternoon to 2 AM EDT Sunday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. Maximum heat index values up to 104. * WHERE. A portion of central Pennsylvania. * WHEN. Until 8 PM EDT Sunday. * IMPACTS. Hot temperatures and high humidity may cause an increase in heat-related illnesses. * ADDITIONAL DETAILS. The risk of heat-related impacts is expected to reach its highest level this weekend. The early season heat persisting over multiple days combined with light winds, limited cloud cover, and very warm nights will exacerbate heat stress.

The Maryland Department of the Environment has issued a Code ORANGE Air Quality Alert Saturday for Northern Baltimore. A Code Orange Air Quality Alert means that air pollution concentrations within the region may become unhealthy for sensitive groups. Sensitive groups include children, people suffering from asthma, heart disease or other lung diseases and the elderly. The effects of air pollution can be minimized by avoiding strenuous activity or exercise outdoors. For more information on ground-level ozone and fine particles visit the web site mde.maryland.gov/programs/air/AirQualityMonitoring/Pages/index.aspx.

The Maryland Department of the Environment has issued a Code ORANGE Air Quality Alert Saturday for the Baltimore City Metro and Annapolis region. A Code Orange Air Quality Alert means that air pollution concentrations within the region may become unhealthy for sensitive groups. Sensitive groups include children, people suffering from asthma, heart disease or other lung diseases and the elderly. The effects of air pollution can be minimized by avoiding strenuous activity or exercise outdoors. For more information on ground-level ozone and fine particles visit the web site mde.maryland.gov/programs/air/AirQualityMonitoring/Pages/index.aspx.