Scorching heat expected in Southwest: Texas, Oklahoma under advisories

Dangerous heat could impact millions over the weekend from the Southwest into the south-central U.S.

Temperatures Saturday afternoon are soaring into the triple digits from Sacramento, California, to Dallas, even topping 110 degrees in Palm Springs, California, and Phoenix.

An excessive heat alert is in effect for cities including Las Vegas, Sacramento, California, and Phoenix.

Nearly all of Texas and Oklahoma are under heat advisories. There are excessive heat warnings for much of Arizona and Southern California.

The worst of the heat wraps up Saturday in the Southwest, easing through early next week as the hot temperatures move eastward. The brunt of heat begins to shift into the center of the country Sunday, and really gets going across the central U.S. Monday into Tuesday.

Widespread, dangerously hot conditions will be in place from the desert Southwest into the south-central US to end the weekend.

Phoenix reached a record-high temperature of 113 degrees Friday and could reach or break its record of 114 degrees on Saturday, set in 1918.

There is also an elevated fire danger on Saturday due to the heat and dry weather.

Dry thunderstorms -- storms that deliver lots of lightning and no considerable rainfall -- are possible across New Mexico and Colorado. The lightning could also raise the risk of wildfires.

Flood watches are in effect for Oregon, Washington, Idaho, and in Montana.

Cooler temperatures are expected in the Northwest over the weekend.

In the East, the weather is expected to be relatively quiet, with no active alerts from Maine to Florida.

The chance of severe weather is focused on a small area from Omaha, Nebraska through Kansas City, Missouri. Strong winds, large hail, and isolated tornadoes are possible Saturday in that area.

Highs on Monday will reach the triple digits once again in Dallas with widespread temperatures above 100 degrees expected across a large swath of the Plains.

The dangerously hot conditions then move into much of the Midwest and Southeast by Tuesday with widespread highs hitting the 90s and heat index values soaring into the triple digits by the afternoon hours. Most of the country will experience hot temperatures in the coming days, the Northeast an exception.

While the heat will ease across the Southwest, the fire danger will ramp back up in parts of the region with another round of strong, gusty winds. The current heat wave and extremely dry conditions will provide ample dry fuels for fires to spread as the winds pick up.

Red flag warnings have been posted beginning on Sunday from southern Nevada to northern New Mexico. Fire weather watches have also been issued for portions of Arizona, New Mexico and Colorado on Monday as the fire danger continues into early next week. These conditions will make it easier for new fires to spark and make it difficult to battle any existing.

The widespread, relentless drought continues across much of the West with little relief expected in the coming days for a large swath of the drought zones. Currently, 90% of the state of New Mexico is facing extreme drought conditions, at level 3 out of 4. The exceptional drought area, where the drought is at a level 4, now encompasses more than 46% of the state.

Overall, more than 85% of the West is experiencing drought conditions with more than 97% of the state of California dealing with a severe drought.

ABC News' Dan Amarante and Dan Peck contributed to this report.