As stifling heat blankets the West, here's what you can expect

Stifling, dangerous weather continued to blanket the West on Monday, coming on the heels of a weekend in which at least five U.S. cities, including Las Vegas, shattered all-time hot temperature records.

The forecast calls for more scorching weather in the West and triple digits in the Midwest on Monday and likely through the remainder of the week.

In the Northeast, temperatures are forecast to soar and air quality to worsen. Factoring in the heat index, which includes high humidity, temperatures in places like Philadelphia, Baltimore and Washington, D.C., will feel like 101 to 102 degrees.

More than 100 million people in 25 states coast to coast are on heat alert, according to the National Weather Service.

New York City was experiencing its hottest day of the year Monday as temperatures spiked to 95 degrees at 1:45 p.m. ET, according to the National Weather Service. The weather service has issued a heat advisory for New York City through 8 p.m. on Tuesday.

Cooling centers throughout New York City were opened Tuesday and city officials encourage anyone without air conditioning in their homes, especially the elderly, to use them. The city Parks Department also announced it is extending the hours of its public pools to 8 p.m. to help residents beat the heat.

"In the West, intense widespread dangerous heat will continue through early next week," the National Weather Service said in a statement. "All-time heat records may be possible in a few locations."

Some of the worst heat will be in the West, where temperatures on Monday are expected to hover near all-time records.

Record highs are expected in Seattle and Portland, Oregon, while Las Vegas will continue to peak near its all-time high next few days.

On Sunday, Las Vegas experienced its hottest day in recorded history when temperatures climbed to 120 degrees, beating the old record of 117 degrees.

At least three cities in California also broke all-time heat records over the weekend, including Palm Springs, which reached a sizzling 124 degrees. On Monday, Palm Springs is forecast to reach 118 degrees.

The sweltering heat will continue across most of California, where temperatures are expected to reach 114 in Redding, 103 in Sacramento and 110 in Fresno.

Raleigh, North Carolina, also saw its highest temperature in history over the weekend, hitting 106 degrees.

The hottest temperature in the U.S. over the weekend was recorded in Death Valley, California, where thermometers climbed to 129, breaking a daily record but falling a few degrees short of its record of 134 degrees set in 1913, which also stands as the hottest temperature ever recorded on Earth. Extreme heat in Death Valley is forecast to continue through the rest of the week and could flirt with breaking the all-time heat record.

At least six motorcyclists visiting Death Valley National Park on Saturday were treated for heat exposure, including one who died, according to the National Parks Service.

By next weekend, the record heat will move into the Rockies, putting Denver and even Rapid City, South Dakota, in a position to see record-high temperatures.