Factbox-Hottest spots in U.S. as heat wave blankets Southwest

(Reuters) - More than 100 million Americans are facing a prolonged spell of sweltering weather into next week, with the National Weather Forecast issuing heat advisories for cities and towns countrywide.

In many places in the Southwest, where hot summers are the norm, extreme temperatures that could break records are predicted.

Here are Saturday's NWS forecasts for some of the Southwest's hot spots: PHOENIX

Forecast high: 115 degrees Fahrenheit (46 Celsius)

All-time record: 122 degrees Fahrenheit on June 26, 1990.

The Arizona city has already had 15 days in a row with temperatures above 110 degrees, and it could break the record 18-day streak set in 1974 before the current heat wave ends.

LAS VEGAS

Forecast high: 115 degrees Fahrenheit (46 degrees Celsius)

All-time record: 118 degrees Fahrenheit on July 26, 1931. The record may fall on Sunday.

Two weeks ago the desert city set a record 291-day streak of consecutive days below 100 degrees Fahrenheit. That broke the previous record of 290 days reached in 1964 and 1965.

DALLAS

Forecast high: 101 degrees Fahrenheit (38 degrees Celsius)

All-time record: 113 degrees Fahrenheit on July 26-27, 1980

In conjunction with the extreme heat, strong winds and a lack of rain have put Central and West Texas counties at an elevated fire risk, according to the Texas A&M Forest Service.

ROSWELL, NEW MEXICO

Forecast high: 106 degrees Fahrenheit (41 Celsius)

All-time record: 114 degrees Fahrenheit on June 27, 1994

Roswell, the legendary center for UFO (unidentified flying objects) sightings, may experience more than three weeks of daily highs exceeding 100 degrees Fahrenheit, according to NWS forecasts.

DEATH VALLEY, CALIFORNIA

Forecast high: 127 degrees Fahrenheit (52 Celsius)

All-time record: 134 degrees Fahrenheit on July 10, 1913

Temperatures in Death Valley, one of the hottest places on earth during summer, are expected to soar over the next week, reaching up to 126 degrees Fahrenheit by Sunday. The outlook has led to concerns about the risk to visitors at Death Valley National Park. Its record of 134 degrees is also the highest global ambient temperature ever recorded.

(Reporting by Rachel Norstrant in New York and Rich McKay in Atlanta; editing by Mark Heinrich and John Stonestreet)