* WHAT. South winds 10 to 15 kt with gusts up to 20 kt expected. * WHERE. Chesapeake Bay north of Drum Point MD, Chester River to Queenstown MD, Eastern Bay, and Choptank River to Cambridge MD and the Little Choptank River. * WHEN. From 1 PM this afternoon to 11 PM EDT this evening. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. Southwest winds around 10 kt with gusts up to 20 kt expected. * WHERE. Tidal Potomac River from Key Bridge to Cobb Island MD, Patapsco River including Baltimore Harbor, and Patuxent River to Broomes Island MD. * WHEN. From 1 PM this afternoon to 11 PM EDT this evening. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. Southwest winds 10 to 15 kt with gusts up to 20 kt expected. * WHERE. Tidal Potomac River from Key Bridge to Cobb Island MD, and Chesapeake Bay and adjoining estuaries north of Drum Point MD. * WHEN. From 1 PM this afternoon to 11 PM EDT this evening. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. Heat index values up to 108 expected. * WHERE. Portions of central, northern 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.

* WHAT. Heat index values up to 102 expected. * WHERE. In Maryland, Washington County. In Virginia, Rockingham, Shenandoah, Frederick, Page, Warren and Clarke Counties. In West Virginia, Morgan, Berkeley and Jefferson Counties. * WHEN. From 11 AM this morning to 8 PM EDT this evening. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses to occur.

* WHAT. Flash flooding caused by excessive rainfall is possible. * WHERE. The District of Columbia, portions of Maryland, including the following areas, Anne Arundel, Central and Southeast Howard, Central and Southeast Montgomery, Prince Georges and Southern Baltimore, and portions of northern Virginia, including the following areas, Arlington/Falls Church/Alexandria, Central and Southeast Prince William/Manassas/Manassas Park and Fairfax. * WHEN. From 2 PM EDT this afternoon through this evening. * IMPACTS. Excessive runoff may result in flooding of poor drainage and urban areas and a few small streams. * ADDITIONAL DETAILS. - Thunderstorms this afternoon and evening could have intense rain rates exceeding 2 inches per hour. If locally repetitive or prolonged thunderstorms develop, flash flooding could occur in flood prone urban and suburban areas. - Please visit www.weather.gov/safety/flood for flood safety and preparedness information

* WHAT. Heat index values up to 102. * WHERE. Adams, Cumberland, Dauphin, Franklin, Lancaster, Lebanon, Perry, and York Counties. * WHEN. Until 8 PM EDT Wednesday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.