Science group predicts hotter weather for Pennsylvania, elsewhere in decades to come

If you think it is too hot and muggy in Western Pennsylvania these days, just wait until it gets worse in a few decades, according to a science advocacy organization that is warning about the dangers of climate change.

The state will experience an average of 40 days a year with a heat index above 90 degrees by 2050, compared to an average of just eight days a year now, according to a new report and peer-reviewed study in Environmental Research Communications, both by the Union of Concerned Scientists. The analysis, titled “Killer Heat in the United States: Climate Choices and the Future of Dangerously Hot Days,” predicts a hotter future that’s hard to imagine today, said the Cambridge, Mass.-based non-profit science advocacy organization.

Pennsylvanians alive at the end of the 21st century will experience an average of 71 days a year when the heat index hits 90 degrees, the group predicts. The heat index, better known as the “feel-like temperature,” takes into account the speed of the wind and humidity to determine how a person’s body actually feels in the temperature.

The organization, which has been criticized by conservative groups, predicts that Allegheny County will have 55 days with a heat index above 90 degrees if nothing is done to slow global warming by mid-century, compared to just 12 now. Both Westmoreland and Armstrong counties would feel the heat index above 90 degrees for 47 days by 2050, up from nine days now.

Though the temperature is expected to feel like it is hotter than 100 degrees this weekend, Pennsylvania historically does not have any days in a year when the heat index reached the century mark. But that would jump to an average of 11 days per year by 2050, and 31 days by 2100, according to the study.

The study started the measurements of the heat index at above 90 degrees because that is the point at which outdoor workers generally become susceptible to heat-related illness. It is the level at which the National Weather Service generally recommends issuing heat advisories and excessive heat warnings, such as in effect for Southwestern Pennsylvania through Saturday night.

A spokesperson for the Union of Concerned Scientists could not be reached for comment.

Joe Napsha is a Tribune-Review staff writer. You can contact Joe at 724-836-5252, [email protected] or via Twitter .