The Fort Smith region is in for more rain this coming week.

National Weather Service officials Friday afternoon predicted the Fort Smith area to receive between a half inch to three-fourths of an inch of rain by July 13. This follows a week in which Fort Smith reached 99 degrees, the highest temperature it has reached this year, on Tuesday and between 1 inch and 1.5 inches of rain in the city's surrounding areas, according to Weather Service records.

This weather pattern, which is common this time of year, is caused by humidity patterns, said Michael Lacy, forecaster at the Tulsa National Weather Service office. Lacy called this pattern "the Earth trying to balance its heat budget."

"The heat and humidity obviously heats the surface, and you get cumulus clouds start to bubble from that, and, given the right conditions, they grow into thunderstorms," he said. "The thunderstorm outflow gives you much cooler air."

Because of the humidity, the heat can feel more oppressive on the human body than the temperature may suggest, Weather Service officials said. At 2:53 p.m. Friday, Fort Smith had a heat index, which factors in humidity, of 109 degrees, according to Weather Service records.

The Fort Smith Fire Department has received a number of heat-related calls in the past week because of the weather, Fire Marshal Carey "Hootie" St. Cyr with the Fire Department said. And when it was raining, the Fire Department received calls for downed power lines, St. Cyr said.

"We do get a number of vehicle accidents due to low visibility or hydroplaning or flooding," St. Cyr said. "We get those with heavy rain pretty much on a consistent basis.”

The rain is predicted to hit the Fort Smith region early next week, Weather Service officials said Friday. Lacy said the rain will follow a cold front he predicted to hit the region over the weekend.

"When the boundary comes down here, it weakens as it goes south, and then eventually, it just kind of washes out, which is going to happen," Lacy said of the front. "It’s going to wash out, and then that heat and humidity will just surge back up to the north again. It’s going to start maybe as soon as Sunday afternoon."

Given the pattern of warm temperatures and downpours, St. Cyr asks Fort Smith residents to be aware of daily temperatures.

“One of the main things is just to keep cool. Keep indoors, where it’s cooler," St. Cyr said. "Keep indoors, hydrate, drink plenty of water and take frequent breaks if you’re working outside and don’t overdo it in the heat, because it will affect you.”

St. Cyr also said Fort Smith residents need to be aware of the possibilites of storms.

"Storms like this are usually associated with lightning, which can be detrimental to one’s health," he said. "Also, be aware of your surroundings. It’s probably not a good idea to stand under a tree or a power line, and if at all possible, it’d be advantageous to slow your driving down."

"You have to prepare for the lightning, so you go indoors, and you have lightning bolts coming down. So go indoors and protect yourself there," Lacy said. "With the heat, obviously, you have to drink plenty of fluids, and also, find some air conditioned areas, if you can.”