Will El Nino make US heatwave worse? Here’s what forecasters say

A powerful “heat dome” has settled over parts of the country, trapping hot air and preventing cooler winds and rain from bringing relief, reported AP citing the National Weather Service (NWS). The system is expected to keep temperatures well above normal for at least a week in many regions.

Meteorologists have urged people to stay hydrated, avoid long periods outdoors and seek air-conditioned spaces whenever possible. They warned that temperatures will remain 15 to 25 degree Fahrenheit (8 to 14 degree Celsius) above average in many places, increasing the risk of heat-related illnesses.

“The heat doesn’t necessarily stop when it’s dark out,” said Josh Adam, a meteorologist with the National Weather Service in Bismarck, North Dakota, as reported by AP. He said temperatures in North Dakota are expected to climb above 100°F (37°C) through Tuesday, even though summer temperatures in the state usually stay in the 80s.

What is causing dangerous heatwave in US?

The extreme weather is being driven by a heat dome, a high-pressure system that traps hot air close to the ground while blocking clouds, rainfall and cooler air from entering the region. According to Chad Merrill, a senior meteorologist with AccuWeather, this is one of the strongest heat domes to affect the Dakotas in the past 25 years, reported AP.

The National Weather Service expects more than 90 local temperature records to be tied or broken through Wednesday. Nearly two-thirds of those records are expected to involve unusually warm overnight temperatures.

Forecasters say night-time temperatures will remain above 80°F (27°C) in cities including Fort Lauderdale, Miami, Tampa, Galveston and Charleston, reported AP. Warm nights make heatwaves even more dangerous because the human body gets little time to cool down and recover.

Several western and central states are expected to experience triple-digit daytime temperatures over the weekend, including Nevada, Utah, Colorado, Wyoming, Idaho, Montana, North Dakota and South Dakota, as reported by AP.

In Las Vegas, temperatures could reach 111°F (44°C) on Saturday. Andrew Gorelow, a meteorologist with the National Weather Service in Las Vegas, said even Nevada, a state accustomed to extreme summer heat, is experiencing temperatures that are higher than normal, reported AP.

Health experts have advised people to drink plenty of water, reduce outdoor activities during the hottest part of the day and regularly check on older adults, children and anyone without access to cooling. The hot and dry conditions could also increase wildfire risk across parts of the Rocky Mountains, where dry thunderstorms may develop over the coming days.

What role are climate change and El Nino playing?

Scientists say climate change continues to make heatwaves stronger, longer and more widespread. The burning of coal, oil and natural gas has increased global temperatures, making extreme heat events more frequent than in previous decades.

Weather experts also expect this year’s temperatures to receive an additional boost from El Nino, a natural climate pattern caused by warming waters in the equatorial Pacific Ocean, reported AP.

Although the current El Nino developed only last month and had little influence on the ongoing heatwave, forecasters expect it to strengthen in the months ahead.

According to the US National Oceanic and Atmospheric Administration (NOAA), the current El Nino has an 81% chance of becoming a “very strong” event by autumn, reported AP. If that happens, it could influence weather patterns across many parts of the world and contribute to even warmer global temperatures later this year.

As the heatwave expands eastward, weather agencies continue to urge people to take the warnings seriously. Prolonged exposure to high temperatures, especially when nights remain hot, can increase the risk of dehydration, heat exhaustion and heat stroke.