* WHAT. Dangerously hot conditions with heat index values up to 110 possible. * WHERE. Portions of central, north central, northeast, northern and southern Maryland, The District of Columbia and central, northern and northwest Virginia. * WHEN. From Monday morning through Monday evening. * IMPACTS. Extreme heat and humidity will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities. * ADDITIONAL DETAILS. Very warm and humid conditions will persist into the overnight hours. Ensure to stay hydrated and find ways to stay cool. Another dangerously hot day is expected on Tuesday.

* WHAT. Dangerously hot conditions with heat index values up to 105 possible. * WHERE. In Maryland, Washington County. In Virginia, Shenandoah, Frederick VA, Page, Warren and Clarke Counties. In West Virginia, Morgan, Berkeley and Jefferson Counties. * WHEN. From Monday morning through Monday evening. * IMPACTS. Extreme heat and humidity will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities. * ADDITIONAL DETAILS. Very warm and humid conditions will persist into the overnight hours. Ensure to stay hydrated and find ways to stay cool. Another dangerously hot day is expected on Tuesday.

* WHAT. During the period of the Excessive Heat Watches, dangerously hot conditions with heat index values around 105 are possible. * WHERE. In Maryland, Washington County. In Virginia, Shenandoah, Frederick VA, Page, Warren and Clarke Counties. In West Virginia, Morgan, Berkeley and Jefferson Counties. * WHEN. For the first Excessive Heat Watch, from Monday morning through Monday evening. For the second Excessive Heat Watch, from Tuesday morning through Tuesday evening. * IMPACTS. Extreme heat and humidity will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities. * ADDITIONAL DETAILS. Very warm and humid conditions will persist into the overnight hours. Ensure to stay hydrated and find ways to stay cool.

* WHAT. During the period of the Excessive Heat Watches, dangerously hot conditions with heat index values up to 110 are possible. * WHERE. Portions of central, north central, northeast, northern and southern Maryland, The District of Columbia and central, northern and northwest Virginia. * WHEN. For the first Excessive Heat Watch, from Monday morning through Monday evening. For the second Excessive Heat Watch, from Tuesday morning through Tuesday evening. * IMPACTS. Extreme heat and humidity will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities. * ADDITIONAL DETAILS. Very warm and humid conditions will persist into the overnight hours. Ensure to stay hydrated and find ways to stay cool.

* WHAT. For the Heat Advisory, heat index values to 104 expected. For the Excessive Heat Watch, dangerously hot conditions with heat index values up to 110 possible. * WHERE. Adams, Cumberland, Dauphin, Franklin, Lancaster, Lebanon, Perry, and York Counties. * WHEN. For the Heat Advisory, from noon today to noon EDT Monday. For the Excessive Heat Watch, from Monday afternoon through Tuesday evening. * IMPACTS. Heat related illnesses increase significantly during extreme heat and high humidity events.