Tuesday marked the third consecutive day the high temperature reached 101° in D.C., which has only happened once before -- in 1930.
D.C. reached 104° Tuesday. Heat indices surpassed 110° in some places across the DMV.
Now, a severe thunderstorm watch is in effect for D.C. and the suburbs until 10 p.m. There could be isolated severe storms through the evening.
Storms could produce wind gusts up to 70 mph, heavy rain downpours in spots and possibly small hail. Tornadoes are not likely.
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Metro, MARC and VRE trains operated with speed restrictions Tuesday because of the heat. Metro limited above-ground train speeds to 35 mph across the system as rail temperatures topped 135°, the agency said. The extreme heat can make the rails expand.
Storm Team4 issued a weather alert, and another excessive heat warning was in effect through 8 p.m.
High heat and humidity may result in heat-related illnesses. Stay hydrated, limit strenuous activity outside and find ways to stay cool today.
Excessive heat warnings are in effect for D.C. and parts of Maryland and Virginia, including Prince George's, Montgomery, Arlington and Fairfax counties. Go here to see all weather alerts.
There is a chance for a few isolated showers and thunderstorms on Tuesday afternoon and evening. Any storms that develop could be severe, like Monday's storms.
Weather Radar
Download the NBC Washington app on iOS and Android to check the weather radar on the go.
Excessive heat throughout midweek
Wednesday will still be hot, but less sweltering with temperatures in the 90s. More rain is expected on Wednesday, but the good news is that cooler air will come in behind the rain. Expect another severe thunderstorm watch Wednesday afternoon.
You can plan on a little relief from the heat starting Thursday. Then, highs are expected to max out in the upper 80s through Sunday.
That cooldown won't last long: Expect to face heat advisories or excessive heat warnings again next week.
Heat safety tips
Intense heat can quickly become dangerous. Keep an eye on vulnerable groups including newborns, infants, children and the elderly.
“Heat is one of the leading weather-related killers in the United States, resulting in hundreds of fatalities each year,” the National Weather Service says.
To stay safe in the heat, stay hydrated and opt for water and sports drinks over sugary beverages. Take shade breaks. Know how to respond to signs of heat-related illness. Avoid strenuous outdoor activities, or move them to the cooler morning hours.
Never leave a pet or kids alone in a parked car. Temperatures in cars can rise to lethal levels within minutes, even with the windows cracked, according to KidsandCars.org.
Wearing loose, light-colored clothing can also help you stay cool.
D.C. says it declares a heat emergency when temperatures or the heat index reach 95°. Cooling centers open during a heat emergency, here's how to find a cooling center plus free transport.
Spray parks and public pools are another way to cool down.
Where can you find a cooling center?
Cooling centers are available in D.C., Virginia and Maryland.
In D.C., free transportation to cooling centers is available by calling 202-399-7093 or 311; find other D.C. resources here.
Arlington County is offering shelters and resources during the heat wave. Financial assistance with air conditioning repairs is available by calling 703-228-1350. Shelter for homeless individuals is available by calling 703-228-1010. Find more information here.
Find cooling centers in Alexandria here.
Montgomery County has issued a heat emergency alert starting at 11 a.m. Thursday, lasting until 9 p.m. Saturday; find resources for the county here.
Find cooling centers in Prince George's County here.
