CNN
—
As summer begins next week, America will show what it can do in a warming world without fossil fuel pollution and the El Niño weather phenomenon.
Parts of the country that have so far been largely spared are heading into a prolonged period of record-breaking heat, increasing the risk of wildfires in parts of the West and threatening bathwater-warm water to spawn the first tropical storm of the Atlantic hurricane season.
Heat arrived in the eastern half of the country on Friday, but it’s just an appetizer of what’s to come.
A vast and extremely powerful heat dome is constructed. A heatwave will swell across the East on Sunday and then spread into the Midwest and Great Lakes over the next few days, bringing the first real heatwave of the year to the region. A heat dome will trap the air and bake it with abundant sunlight every day, making each day hotter than the one before.
This will cause temperatures to be even higher than on the hottest typical summer day.
Hundreds of temperature records, both day and night, could be broken by next weekend.
Temperatures will be 15 to 20 degrees above normal across much of the eastern U.S. on Monday afternoon, but will get even warmer Tuesday through Friday, possibly reaching 25 degrees above normal.
This means sustained days of temperatures exceeding 90 degrees Celsius for tens of millions of people who are not normally exposed to prolonged heat.
View this interactive content on CNN.com
There’s no escaping the heat at night, another sign of global warming: Overnight lows are not expected to drop below the low 70s Fahrenheit or upper 60s Fahrenheit in many places.
To make matters worse, the humidity is combining with the heatwaves to send heat indices — how hot a person feels — into dangerous triple digits in parts of the east, with northern Maine potentially seeing heat in the low 100s next week.
The National Weather Service and the Centers for Disease Control and Prevention predict that heat-related health risks will reach extreme levels affecting millions of people next week. Extreme heat is the deadliest weather event in the United States, killing more than twice as many people each year as hurricanes and tornadoes combined, on average.
The Atlantic hurricane season appears to be waking up just as scorching summer heat hits much of the country.
There are two short-term danger areas that could develop the year’s first tropical cyclone, both too close to the U.S. coast for relief.
The southwestern Gulf of Mexico region will most likely become a tropical cyclone at first, and there’s also a slight chance that the same storm pattern bringing rains to Florida could develop into a tropical cyclone off the Southeast Coast before being pushed out to sea this weekend.
Tropical moisture is swirling around the southwestern Gulf of Mexico due to the Central American Gyre, a large, chaotic region of showers and thunderstorms that rotates around Central America and the surrounding waters.
The gyre’s wide rotation and abundant moisture could help tropical systems form in the Caribbean, Gulf of Mexico and even parts of the far eastern Pacific Ocean if other necessary factors, such as favorable upper-level winds and warm waters, line up.
That could happen by the middle of this week. The National Hurricane Center says there’s a moderate chance of a tropical storm developing in the Bay of Campeche in the southwestern Gulf of Mexico. Because much of the Gulf is as warm as a bathtub, if a tropical storm does form, it will have enough energy to strengthen. If it does form, it will likely track north or northwest.
With or without tropical development, a surge in moisture like the one that caused heavy rains in South Florida would bring much-needed rain to parts of Mexico that have been hit by weeks of scorching heat and severe drought.
But it will also increase the risk of flooding along the Gulf Coast, especially in areas hit hard by flooding this spring.
Several days of rain are expected along the Gulf Coast from Texas to Alabama, beginning Sunday and continuing through the week.
The heat is making us sweat and fueling hurricane season, as well as contributing to some recent notable wildfires.
Fire activity is gradually increasing across the country, with nearly 10 large fires burning in parts of the West, half of them in the past few days, according to the National Joint Fire Center.
The hot, dry weather that has continued in the West since the beginning of the month continues to increase the risk of wildfires and may exacerbate ongoing fires. During this period, wildfire fuels such as grass and vegetation continue to dry out, increasing the likelihood of fire ignition and spread.
Winds will also pick up in the region later this weekend and early next week. Gusty winds can cause wildfires to spread quickly, as was demonstrated by the Corral Fire in California in early June.
Strong winds could also cause problems next week for the Rose Fire, a small but destructive blaze burning about 70 miles northwest of Phoenix, Arizona.
The Arizona Department of Forestry and Fire Management said Thursday that the fire destroyed at least 15 structures, seven of which were homes, and at least 12 vehicles.
The fire has burned at least 166 acres since it started Wednesday but was only 20 percent contained as of Thursday evening.
Arizona Department of Forestry and Fire Management/AP
Smoke filled the sky as the Rose Fire burned southeast of Wickenburg, Arizona, on Wednesday.
CNN’s Paradise Afshar contributed to this report.
