Thursday is expected to be cloud free with temperatures rising more in the afternoon to reach a high of 89, and that mix has prompted an air pollution advisory for ground-level ozone.

The advisory will be in effect for the counties of Butler, Clark, Clermont, Greene, Hamilton, Miami, Montgomery and Warren as the forecast possibly could lead to higher levels of air pollution because sunlight mixes with emissions from vehicles and small gasoline-powered engines, according to the Miami Valley Regional Planning Commission, which issued the advisory.

The air quality index is expected to reach 104. Any reading higher than 100 is deemed unhealthy for sensitive groups.

According to Storm Center 7 Chief Meteorologist Jamie Simpson, Friday will be sunny until sunset. That’s when the first high clouds are expected to arrive ahead of Isaac, the storm that reached landfall this week in Louisiana.

Afternoon highs will be in the low 90s. The area should be dry for football games on Friday night.

By sunrise Saturday, the area could be experiencing the first showers from the remnants of Isaac. The day will not be horribly wet, but showers will begin to increase in the afternoon and progress to a steadier rain by Saturday night.

Sunday and Monday will be wet, although it may not rain all day on Monday. Rain should taper off into the evening, leaving possible rain totals of 2 to 5 inches by Monday night. There is a greater chance of the higher rain totals north than south.

The expected rainfall may lead to some stream and creek flooding, but perhaps not until Monday. The dry ground will act like a sponge to some degree, soaking up a lot of water, Simpson said.