100-Degree Heat Index Values Prompt Advisory In NoVA, DC

WASHINGTON, DC — Northern Virginia and DC will be under a heat advisory Wednesday as heat index values of 100 degrees or higher impact the region.

The National Weather Service's Baltimore-Washington office issued the heat advisory from noon to 8 p.m. Wednesday. Forecasters expect even hotter temperatures Thursday and will issue an excessive heat watch from the afternoon to early evening.

Heat index values will vary by area on Wednesday. The NWS expects 100-degree heat index values west of Interstate 95 and 105 degrees near and east of I-95. For the excessive heat watch, forecasters say "dangerously hot conditions are possible" with heat index values ranging from 105 degrees west of I-95 to 110 degrees near and east of Interstate 95.

The advisory and watch apply to the District of Columbia, Prince William County, Manassas, Manassas Park, Fairfax County, Arlington County, Falls Church, Alexandria, Stafford County, Spotsylvania County, King George County, Fredericksburg, Fauquier County, and Loudoun County.

Extreme heat and humidity conditions increase potential for heat-related illnesses like heat cramps, heat exhaustion and heat stroke. Residents can learn the symptoms of each heat-related illness and how to respond.

The NWS urges residents to drink plenty of fluids, stay in air-conditioned spaces and out of the sun, check on neighbors and relatives, and avoid leaving young children and pets unattended in a hot car.

Here is the NWS forecast for DC over the next few days.

Tuesday: Scattered showers and thunderstorms, mainly after 3 p.m. Sunny, with a high near 94. Heat index values as high as 101. At night, showers likely and possibly a thunderstorm before 9 p.m., then a slight chance of showers and thunderstorms between 9 p.m. and midnight. Some of the storms could produce gusty winds and heavy rain. Partly cloudy, with a low around 75. The chance of precipitation is 40 percent during the day and 60 percent at night.

Wednesday: A chance of showers and thunderstorms after 3 p.m. Sunny, with a high near 96. Heat index values as high as 106. A chance of showers and thunderstorms before midnight. Mostly cloudy, with a low around 77. Chance of precipitation is 40 percent.

Thursday: A slight chance of showers between 9 a.m. and 3 p.m., then a chance of showers and thunderstorms after 3 p.m. Mostly sunny and hot, with a high near 100. A chance of showers and thunderstorms, mainly before 9 p.m. Partly cloudy, with a low around 77. Chance of precipitation is 30 percent.

Friday: A chance of showers and thunderstorms after 3 p.m. Mostly sunny, with a high near 95. A chance of showers and thunderstorms before 9 p.m., then a chance of showers between 9 p.m. and 3 a.m. Partly cloudy, with a low around 75. Chance of precipitation is 40 percent.