The first prolonged period of summer-like heat also is bringing the first episode of unhealthy air quality to the Rock Hill area this week.
High pressure centered over the Southeast is forecast to create rather stagnant air movement, and the S.C. Department of Health and Environmental Control is predicting elevated ozone levels for York, Lancaster and Chester counties.
Similar conditions are likely Wednesday and Thursday.
“It looks like summer for the middle and late part of the week,” says Pat Moore, of the National Weather Service office in Greer.
Rock Hill recorded a high of 86 degrees Monday, and forecasters say they expect afternoon temperatures to climb a bit higher Tuesday and Wednesday. Readings of 90 degrees are possible both days in the Rock Hill area.
The Air Quality Index for York, Lancaster and Chester counties on Tuesday is expected to be 80, which is “Moderate.” Under those conditions, only people who are extremely sensitive to unhealthy air are urged to limit outdoor activities during the peak heating hours.
Ozone, a gas created by the combination of sunlight on carbon emissions (such as those from vehicle engines), will be the main pollutant the next few days, authorities say.
An Air Quality Index of 101 is forecast just to the north, for Mecklenburg and several surrounding N.C. counties. A Code Orange alert is in place there, and people who have asthma and other chronic respiratory problems are being urged to limit outdoor activities.
No change in conditions is expected until the weekend, with high pressure dominating the Southeast. Humidity levels are forecast to remain low through Thursday, with daily highs approaching 90. But the humidity will climb by Friday and Saturday.
The next chance for rain is expected Sunday, as a frontal system approaches the area.
The long-range forecast indicates that this week’s taste of summer might be relatively short-lived. Government meteorologists are predicting a good chance of below-average temperatures from around May 25 through the end of the month.