People play in the hydrant's spray. At the 3rd and Spruce Recreation Center in Reading Wednesday afternoon June 24, 2020 for the first Wacky Water Wednesday.
Ben Hasty | Read Eagle | Getty Images
A reinforcing heat dome brings oppressive heat to the US this summer. Almost 90% of the country's population will be exposed to temperatures above 90 degrees Fahrenheit this weekend.
Areas in Oklahoma this week reached heat indexes above 115 degrees and New Orleans indexes above 120 degrees. In Texas, temperatures in Austin and San Antonio reached July records, and Houston reached 100 degrees with a heat index of 111 degrees. Phoenix also reached a blistering 111 degrees on Tuesday.
The National Oceanic and Atmospheric Administration has already warned of a scorching summer with high heat indices due to a mixture of high temperatures and high humidity, which further aggravates public health concerns as coronavirus cases are increasing in many states.
The extreme heat is due to a strong and persistent high pressure system that sits over the United States and is often referred to as a heat dome. The high pressure air rises from above, compresses and heats up near the ground and already worsens hot summer temperatures on Earth. Heat domes are likely to be heavier when the climate changes.
"It is called the" dome "because of its size and shape, and because the heat is trapped on the surface – because more and more air descends on it – which can lead to heat buildup days," said Flavio Lehner, a climate researcher at the Institute for Atmospheric and Climate Science at ETH Zurich.
The heat dome also prevents clouds from forming when the air descends. Clouds form when air rises and reaches cooler layers at higher levels in the atmosphere and then cools and condenses. However, the dome creates an opposite effect, in which the air rises and warms up instead of rising and cooling, creating a sunny sky with no cloud cover.
"At some point the weather will change and the dome will slide out, but this particular situation is special about how slowly it moves," said Lehner.
The sun sets behind the Statue of Liberty as it is partially covered by heat waves from the exhaust of a passing ferry on May 31, 2020 in New York City.
Gary Hershorn | Getty Images
The heat wave also has some origins with the June Siberian heat dome, which, according to Judah Cohen, a climatologist at atmospheric and environmental research, led to record heat that penetrated central Arctic and accelerated the melting of ice there.
"Typically, these high pressure systems are located above the oceans like the well known Bermuda High," said Cohen, referring to a subtropical high pressure area in the North Atlantic that is increasing as the planet warms. "However, the Bermuda high is predicted to move west across the central United States, and this dome will do that."
The heat wave exposes people who are most susceptible to coronavirus infection to an increased risk of illness from high heat and moisture.
High humidity also worsens the heat and prevents temperatures from dropping at night. This creates problems for people who sleep without air conditioning.
"If you have a & # 39; heat dome & # 39; … in midsummer, adding 5-10 ° F to a typical high temperature will take you straight into the 90s, close to 100 ° F for a large population of the United States" said the BAM weather meteorologist Ryan Maue.
While around 90% of U.S. households have air conditioning, according to the U.S. Census, a disproportionately large number of low-income or minority people don't have it in their homes, the same population group that is most affected by Covid-19.
In many cities, there are usually refrigeration centers for public use, but the corona virus has raised major health concerns about the use of such spaces, and in some cases centers have been closed during the pandemic.
2020 is expected to be one of the hottest 10 years ever accelerating climate change. 2019 was the second hottest year ever and topped the hottest decade in the world in history.