(RNN) – Amid a heat wave in the Northeast and Midwest, the National Weather Service wants to remind everyone that heat can kill, and people should take precautions ahead of the July 4 holiday.
A heat dome, or an area of high pressure at high altitudes, is expected to cover most of the United States by the middle of the week, according to the Washington Post. It has already begun affecting the Northeast.
With the dome comes heat: temperatures are expected to reach into the 90s, with humidity making it feel more like 105 or 110 degrees.
Nighttime temperatures, which AccuWeather forecasts will only drop to the middle or upper 70s, will not help with cooling.
The heat wave is expected to persist for six to eight days in many communities, according to AccuWeather, with peak intensity hitting Monday.
"It will not only be very hot, but it may also be perceived as relentless for many people in the Northeast as the heat lingers into the first part of July," said Paul Pastelok, a long-range meteorologist with AccuWeather.
Eighteen states have issued heat advisories, warnings or watches, USA Today reports.
"Heat kills more people each year than any other weather hazard, including tornadoes, lighting and floods," wrote the NWS on Twitter Friday.
Everyone is urged to take precautions against the heat, especially people who will be spending time outdoors during the heat wave.
"People of all ages, regardless of their health and physical activity, indoors and out, will need to stay hydrated. Intake of alcoholic beverages should be limited, especially when there is no means to keep cool, such as in air conditioning," said AccuWeather Senior Meteorologist Alex Sosnowski.
In addition to drinking plenty of water, the NWS advises wearing lightweight clothing and restricting strenuous activities to early morning or evening.
The elderly, children, homeless and pets will be especially vulnerable, according to AccuWeather.
Children and pets should not be left alone in vehicles, and everyone should watch out for the symptoms of heat exhaustion and heat stroke.
It is likely energy costs will also increase due to the strain of the heat and humidity.
AccuWeather warns those in the Northeast may be particularly affected by the heat wave because this is the longest stretch of such high temperatures in the area since 2016 or longer.
The heat dome may weaken by the end of the week, according to the Washington Post, but it is too soon to tell if that will be the case.