Tropical rainstorm Barry's path eastward isn't likely to result in much rain to Lancaster County. But the moisture from the system, which made landfall along the Louisiana coast Saturday, is poised to bring "dangerous" heat indexes to the region, according to the National Weather Service.

The third week in July is often the warmest week of the summer in Lancaster County. Millersville University meteorologist Eric Horst said in a tweet that several 90-degree days in the forecast are "right on schedule."

Although there have been warm and muggy days this summer, Lancaster County has yet to have a meteorological heat wave — three, consecutive 90-degree days, Horst said.

That could change by the week's end.

Humidity should increase Tuesday with a high in the 80s. There's a chance of showers between 3 and 8 p.m., according to National Weather Service meteorologist John Banghoff. 

The real heat begins Wednesday. 

With forecast highs in the 90s, temperatures could feel more like 100 degrees. That trend should continue through the weekend. By Friday and Saturday, forecast highs in the mid-90s could feel more like 105 degrees, Banghoff said.

"We're expecting heats indexes to approach pretty dangerous levels during the day on Friday and Saturday," he said. 

Banghoff encouraged people to begin to prepare now for the hot weather.

"Stay hydrated. Reduce exposure to warm conditions," he said.

He expects reports of heat exhaustion and heat stroke.

"We haven't really experienced a whole lot of heat so far this summer," Banghoff said.

A cold front late Sunday into Monday should break the pattern of heat, he said.