* WHAT. Heat index values up to 101 expected. * WHERE. A portion of central Pennsylvania. * WHEN. From noon today to 8 PM EDT Friday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

* WHAT. Heat index values up to 100. * WHERE. Central Pennsylvania. * WHEN. Until 8 PM EDT Friday. * 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 Sandy Point MD to Smith Point VA, Tidal Potomac from Cobb Island MD to Smith Point VA, Eastern Bay, Choptank River to Cambridge MD and the Little Choptank River, and Tangier Sound and the inland waters surrounding Bloodsworth Island. * WHEN. Until 1 AM EDT Wednesday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. For the Heat Advisory, heat index values up to 96 expected. For the Excessive Heat Watch, dangerously hot conditions with heat index values up to 105 possible. * WHERE. Portions of northern Delaware, New Jersey, and southeast Pennsylvania. * WHEN. For the Heat Advisory, from 10 AM this morning to 6 AM EDT Thursday. For the Excessive Heat Watch, from Thursday morning through Sunday evening. * IMPACTS. Heat related illnesses increase significantly during extreme heat and high humidity events.