By Amy Tennery
NEW YORK, June 29 (Reuters) - Extreme heat will greet fans and players this week at the World Cup, as an imposing "heat dome" settles over the central and eastern United States - plus parts of Canada - as the knockout rounds progress.
The weather phenomenon known as a "heat dome" - a large area of high pressure that traps heat and humidity - could lead to dangerously high temperatures, with heat indices set to hit 105 to 115 degrees Fahrenheit in parts of the Midwest and East Coast,
according to the U.S. National Weather Service.
Those conditions are set to extend through the Fourth of July holiday weekend in the U.S., which is celebrating its 250th anniversary, with matches from Toronto to Kansas City to East Rutherford, New Jersey and Philadelphia all feeling the heat.
"Even after the sun goes down, it's still going to be very hot," said AccuWeather Senior Meteorologist Alan Reppert. "We're at a pattern that's really going to be hot during the good portion of the afternoon and even into the evening hours."
Reppert projects that New York, which will welcome fans for a Round of 16 match in nearby New Jersey on July 5, will see temperatures reach their highest levels since 2013. He added that even matches played in the evening could be affected.
"The sun will be down," he said. "That will help make things better, but it's still going to be hot."
HYDRATION BREAKS FEATURE AT TOURNAMENT
The conditions have the potential to reignite the issue of player safety and welfare that came up a year ago during the Club World Cup, which was held in the U.S., when FIFPRO said the scorching weather should serve as a "wake-up call."
FIFA instituted mandatory three-minute hydration breaks in each half in every match for the World Cup this year, a measure that supporters say benefits player welfare but critics argue disrupts the flow of play at the tournament.
World Soccer's governing body did not immediately respond to a request for comment on any additional measures that could be taken for player or fan safety during the expected period of intense heat.
Toronto, which will host a Round of 32 match between Portugal and Croatia on Thursday, put its "Heat Relief Strategy" into effect after Environment and Climate Change Canada issued a heat warning that runs from Tuesday through Friday.
Three of the stadiums hosting matches under the umbrella of the heat dome - Atlanta, Dallas and Houston - have retractable roofs and air conditioning, offering significant relief.
But even the stroll to the modern home of the Dallas Cowboys can feel more like a firewalk, with the concrete-and-asphalt-laden Texas city built for cars and primed to absorb heat.
Alina Mitina, an emergency department physician for Hackensack University Medical Center in New Jersey, said fans should seek out shade as much as possible and watch out for telltale signs of heat-related illness, including dizziness.
"Shady areas will really save lives in these types of situations," said Mitina. "So as long as there's lots of shade and areas to buy water, I think they're going to be in really good shape."
(Reporting by Amy Tennery in New York, additional reporting by Bhargav Acharya in Toronto, Lori Ewing in Kansas City and Malgorzata Wojtunik and Manuel Ausloos in Dallas; Editigng by Ken Ferris)
