The heat warning for the D.C. area kept the parks empty and strained the Metro air conditioning system. It's not just people who are suffering in the heat.
You probably saw this coming, too. Three straight days of 100 degrees have been in the forecast all week, so why not three straight days of excessive heat warnings?
A warning has been issued for Saturday from 10 a.m. to 8 p.m. Furthermore, today's warning has been expanded by four hours and will be in effect from 10 a.m. until 10 p.m.
News4 Chief Meteorologist Doug Kammerer doesn't expect any record high temps, but highs of 100 three days in a row has only happened three times before in D.C. history.
We didn't quite get there Thursday, at least not at Reagan National Airport, where the high reached 99 degrees and the heat index 112.
By 2:30 p.m. Thursday, the heat index had reached 120 in Calvert County, Md., and 125 in Fredericksburg and Warrenton in Virginia, Kammerer reported. Late Thursday afternoon, the heat index was at 118 in LaPlata and 119 in Huntingtown.
Friday will be worse, Kammerer said. He again expects a possible high of 101 Friday and triple digits again Saturday before we see any relief from a cold front expected to move in Saturday night and into Sunday morning.
Along with the heat and humidity, the region also has to deal with poor air quality. The breeze helped out Thursday, but it will not hang around for Friday, meteorologist Chuck Bell reported. A Code Red air quality alert will be in effect Friday. Everyone should limit strenuous outdoor activity because the air is unhealthy to breathe. Turn off as many lights and appliances as possible, don't drive if you don't have to, do not apply chemicals to your lawn or garden, and avoid mowing.
Stay indoors if you can, but if you have to go out, keep your physical activity to a minimum. Stay hydrated and look out for the elderly and pets.
In the midst of the skyrocketing temps, one of the old standbys for staying cool -- the Warwick Pool in Alexandria, Va. -- temporarily closed due to a telephone outage, because health department guidelines insist a public pool can't be open without a working landline. The pool had reopened before 3 p.m.
Maryland State Police are on the look out for stranded drivers to help them in the heat. Troopers are directed to help drivers with disabled vehicles as quickly as possible through Friday, police said. Drivers should be sure to carry plenty of water and a working cell phone and, of course, should not leave a child or pet in a car alone.
Virginia State Police also are on heightened alert for disabled vehicles. They're asking motorists to make sure their vehicles are in top shape, their gas tanks and other fluids filled, and their tire air pressure checked. But if you do need to fill your gas tank, try to do it early or late when the heat isn't so bad because of the air quality.
The Maryland Transit Administration is taking steps to protect MARC trains, equipment and passengers during the heat wave, saying the severe heat pushes equipment to the limit. The agency will aggressively address issues as they occur and resolve them as quickly as possible.
In June 2010, hundreds of passengers were stranded for two hours on a broken-down MARC. Several were treated for heat-related issues.
At Union Station in Washington, water coolers will be provided.
Metro riders should remember that the transit agency is often dealing with air conditioning problems, so if you wind up on a hot car, get off at the next stop, walk down two cars and get back on. Metro railcars operate as pairs so every two cars share the same problem.
Power companies are preparing to deal with outages. Pepco and Baltimore Gas & Electric say the region's power supply is expected to be enough to meet demand, but the utilities are advising customers to take steps to save energy. Pepco and BGE are staffing to quickly address any equipment issues that may arise from heat or potential storms resulting from the heat.
This NOAA animation shows the predicted high temperatures through Thursday:
Weather on the Web: Get the latest weather from NBCWashington.com anytime, anywhere:
Follow us on Twitter and Facebook. Sign up for our e-mail newsletters and get breaking news delivered right to your mobile phone -- just text DCBREAKING to 622339 to sign up. (Message and data rates may apply.)