Americans coast-to-coast sweat out historic heat wave

Las Vegas topped the 110-degree mark for the eighth consecutive day.

More than 150 million people were under heat alerts coast-to-coast Wednesday afternoon as temperatures soared into the triple-digits in the West and hot, humid weather in the East and South made it feel like it was over 100 degrees.

A historic heat wave that has gripped the nation for days continued Wednesday as places like Las Vegas topped the 110-degree mark for the eighth consecutive day. Fresno, California, is expected to surpass 105 degrees Wednesday afternoon for the eighth straight day, according to the National Weather Service.

Las Vegas, which recorded its highest temperatures ever on Sunday when it reached 120 degrees, broke another weather record on Wednesday. The city experienced its fifth straight day of temperatures reaching 115 or above, beating its old mark of four consecutive days of such high heat set in 1940 and tied in 2005.

Sin City could also break its record of 10 consecutive days of 110 degrees or higher by the end of this week. The temperature in Las Vegas is forecast to climb to a blistering 118 degrees on Thursday, 115 on Friday and 112 on Saturday, according to the National Weather Service.

Elsewhere in the West, an excessive heat warning has also been issued for Phoenix, Arizona, where the high is forecast to be 113 degrees on Wednesday afternoon, and 115 on Thursday and Friday.

Salt Lake City, Utah, is forecast to reach 102 degrees on Wednesday afternoon, 105 degrees on Thursday and 104 on Friday. Boise, Idaho, is expected to hit 107 degrees on Wednesday afternoon before dipping to 106 on Thursday and back to 107 on Friday, according to the weather service.

Once again, the hottest place in the nation Wednesday was Death Valley, California, where the temperature shot up to 123 degrees at 2 p.m. local time from 99 degrees at 5 a.m. The high for Wednesday in Death Valley's Furnace Creek area is forecast to hit 127.

The all-time record high for Death Valley is 134 degrees set in July 1913, according to the National Weather Service.

On the East Coast, Philadelphia, in particular, has been scorching hot lately. On Tuesday, the City of Brotherly Love experienced its eighth straight day of high temperatures at or above 95 degrees. Normally, Philadelphia averages seven days for the whole summer when the temperature hits 95 or above.

On Wednesday afternoon, it was 93 degrees in Philadelphia.

Factoring in the heat index, which includes high humidity, Philly was expected to feel more like 105 degrees on Wednesday afternoon, while Washington D.C. was expected to feel like 109 degrees and Raleigh, North Carolina, like 108 degrees, according to the weather service.

Wednesday evening could bring a much-needed break from the sweltering conditions as showers and thunderstorms move across the Great Lakes and into the Northeast.

A tornado watch is also in effect until 9 p.m. ET Wednesday for parts of Pennsylvania, New York and Vermont.