103-Degree Heat: Timeline For Severe NoVA, DC Weather

WASHINGTON, DC — Heat and dangerous humidity will combine Monday, Aug. 19, to smother northern Virginia and Washington, D.C., with a high temperature in the afternoon expected to feel like 103 degrees at the hottest time of day, according to the National Weather Service. The heat index incorporates the actual temperature and humidity to determine how hot it will feel like it is outside.

It will feel hotter than 100 degrees between noon and 7 p.m. in much of the Washington metro, with the peak of the heat expected to hit from 1 to 6 p.m. when it should feel like 100 degrees or more in the region. And it doesn't cool off much overnight. The low on Tuesday morning will be 78 degrees.

Also, a hazardous weather outlook is in place for the Chesapeake Bay, Tidal Potomac River, and adjacent counties in northern Virginia as well as the District of Columbia. A thunderstorm may produce gusty winds on the waters Monday into the evening. Thunderstorms may produce isolated damaging wind gusts and isolated instances of flooding on Tuesday.

Here's the timeline to 103 degrees on the heat index in the Washington, D.C., area, based on the forecast:

• 12 p.m.— 96 on heat index; actual 90
• 1 p.m. — 100 on heat index; actual 94
• 2 p.m. — 103 on heat index; actual 97
• 3 p.m. — 102 on heat index; actual 96
• 4 p.m. — 102 on heat index; actual 96
• 5 p.m. — 102 on heat index; actual 95
• 6 p.m. — 100 on heat index; actual 93
• 7 p.m.— 98 on heat index; actual 91
• 8 p.m.— 95 on heat index; actual 88
• 9 p.m. — 92 on heat index; actual 86
• 10 p.m. — 91 on heat index; actual 85
• 11 p.m. — 88 on heat index; actual 83

Signs Of Heat-Related Illness

Watch for signs of heat exhaustion and heat stroke.

Get medical help immediately if these occur:

• Confusion
• Nausea
• Lightheaded feeling
• High body temperature with cool and clammy skin
• Hot, dry, flushed skin
• Rapid or slowed heartbeat

Individuals having a heat-related medical emergency or who are experiencing the signs of heat exhaustion or heat stroke should call 911.

Heat To Continue This Week: Forecast

Below is the DC/northern Virginia forecast from the National Weather Service.

Monday: Scattered showers and thunderstorms, mainly after 2pm. Partly sunny and hot, with a high near 97. Heat index values as high as 103. Southwest wind around 6 mph. Chance of precipitation is 50%.

Monday Night: Scattered showers and thunderstorms, mainly before 8pm. Mostly cloudy, with a low around 76. Southwest wind around 6 mph becoming calm after midnight. Chance of precipitation is 30%.

Tuesday: A slight chance of showers between 11am and 2pm, then a chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 94. Heat index values as high as 100. Light and variable wind becoming southeast around 6 mph in the morning. Chance of precipitation is 40%.

Tuesday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 75. South wind around 6 mph becoming calm after midnight. Chance of precipitation is 40%.

Wednesday: A slight chance of showers, then a chance of showers and thunderstorms after 8am. Partly sunny, with a high near 94. Southwest wind 3 to 8 mph. Chance of precipitation is 40%.

Wednesday Night: A chance of showers and thunderstorms. Partly cloudy, with a low around 76. Chance of precipitation is 40%.

Thursday: A chance of showers and thunderstorms. Partly sunny, with a high near 91. Chance of precipitation is 50%.

Thursday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 68. Chance of precipitation is 50%.

Friday: A chance of showers and thunderstorms. Partly sunny, with a high near 83. Chance of precipitation is 40%.

Friday Night: A chance of showers and thunderstorms. Partly cloudy, with a low around 66. Chance of precipitation is 40%.

Saturday: A chance of showers and thunderstorms. Mostly sunny, with a high near 84. Chance of precipitation is 30%.

Saturday Night: Partly cloudy, with a low around 66.

Sunday: Mostly sunny, with a high near 85.