A high-pressure system that’s settled over Arizona continues to produce dangerous heat in the Phoenix area.

The extended National Weather Service forecast for the Phoenix area includes highs up that could reach 117 degrees. Forecasters said the worst of the heat will come at the end of the week.

The normal average high for July is 106.5 degrees, Isaac Smith, a meteorologist with the National Weather Service office in Phoenix, told NPR.

The scorching temperatures come after eight consecutive days of highs above 110 degrees in Phoenix. The combination of hot, dry and windy conditions could also lead to fires, according to the Weather Service.

The excessive heat warning, which started on July 1, is expected to end on July 16. But Smith said there is a chance that the advisory, along with the extreme weather, will last beyond that.

Meanwhile, highs in Tucson will range between 108 to 115 degrees. A heat warning is in effect until Thursday. Over the weekend, the city is also expected to see some thunderstorms, caused by monsoon moisture building up along the state's border with Mexico.

And it’s not just the daytime temperatures that are of concern.

"The relief from the overnight hours is going to become less and less with time, too," said lead forecaster Alex Young.

Young advises people to stay indoors and someplace cool. Water is a huge priority.

“It’s very easy to get dehydrated in these conditions even if you’re inside. So obviously try to drink as much as you feel necessary," said Young.

Temperatures will be too high for the nights to properly cool. Young says to expect overnight lows in the upper 80s to lower 90s for at least the coming week. The potential for sustained and intensified heat grows as the high-pressure weather system hangs around.

"There can be a feedback process where if there’s an extended period where the pattern sits over one place, that can lead to hotter and hotter temperatures," said Young.

Young says it’s easy to become dehydrated in these conditions, even when staying indoors