Friday could be this week’s hottest day in Upstate

Summer’s first extended period of heat and high humidity is enveloping the Rock Hill area this week, and meteorologists say local residents will need to take precautions.

High temperatures are forecast to approach the mid 90s, but high humidity will create heat indices of 100 degrees or higher. The heat index is the “real feel” of the temperature, combining the impact of heat and humidity.

What’s more, forecasters say, there won’t be much relief at night.

There have been 13 days of 90 degrees or more so far this summer at the Rock Hill Airport, with the highest being 93. That could be eclipsed any day this week, according to National Weather Service forecasters.

The hottest day could be Friday, according to the Weather Service’s Harry Gerapetritis. He said the combination of a forecast high of 94 degrees for Rock Hill, along with the humidity, could bring a heat index in the lower 100s.

Only a few spots will get lucky with a late-afternoon or evening thunderstorm through Thursday, meteorologists say. An isolated storm popped up Tuesday afternoon in Chester County, but the rest of the Rock Hill area stayed hot and rain-free.

Thunderstorm chances are expected to increase by Friday and into the weekend, and the heat wave should begin to relent by Sunday or Monday, according to forecasters.

“In addition, there will be little relief at night, especially in the urban corridors, where lows will be in the low to mid 70s,” said meteorologist Lauren Carroll, of the Weather Service’s office in Greer.