* WHAT. Up to one half foot of inundation above ground level expected in low lying areas due to tidal flooding. * WHERE. Shoreline in Anne Arundel County. * WHEN. From 1 AM to 7 AM EDT Tuesday, especially around the time of high tide. * IMPACTS. At 2.8 feet, flooding of some of the parking area near Dock Street in Annapolis may occur, with water surrounding the Alex Haley Memorial. * ADDITIONAL DETAILS. Tides one to one and a half feet above normal. The next high tide at Annapolis U.S. Naval Academy is at 3:35 AM.

* WHAT. South winds 10 to 20 kt with gusts up to 25 kt. * WHERE. Chesapeake Bay from Pooles Island 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 6 AM EDT Tuesday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. Heat index values up to 101 expected. * WHERE. In Maryland, Washington and Central and Eastern Allegany Counties. In West Virginia, Eastern Mineral, Berkeley, Jefferson, and Morgan Counties. * WHEN. From noon to 8 PM EDT Tuesday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

* WHAT. Heat index values up to 100 expected. * WHERE. Central Pennsylvania. * WHEN. From noon Tuesday to 8 PM EDT Thursday. * IMPACTS. Hot temperatures and high humidity may cause heat-related illnesses. * ADDITIONAL DETAILS. The heat wave is expected to continue into the weekend with the hottest temperatures of the summer so far. The longevity of the heat wave has not been experienced in decades during the month of June.