Heat warning for Philly area

The Philadelphia region is under an excessive heat warning Wednesday as the area braces for the second day of what's expected to be an extended heat wave.

The National Weather Service is calling for high temperatures to reach above 90 every day through at least Tuesday.

The heat warning is in place from noon Wednesday through 6 p.m. Thursday.

During that time span, forecasters say, heat index values could soar to near 100 degrees.

After a high of 93 degrees Tuesday, the mercury is expected to hit the low-to-mid 90s again both Wednesday and Thursday.

But it will feel hotter due to high humidity. The weather service is also warning residents not to expect much nighttime cooling, as temperatures are expected to dip only as far as the upper 70s overnight.

In response to the heat warning, the Philadelphia Corporation for Aging is opening 23 air-conditioned senior community centers and activated its heatline (215-765-9040) to provide advice and response services if needed.

People who work or spend significant time outside are encouraged to take precautions like rescheduling strenuous activities for the early morning or evening, knowing the signs of heat illnesses, wearing lightweight and loose-fitting clothing, and drinking enough water.

While the string of 90-plus temperatures is expected to continue, the humidity should drop starting on Friday, the weather service said.

But with a return to highs below 90 forecasted for the middle of next week, Philadelphia shouldn't approach its record for consecutive 90-degree days. That record stands at 18 days, set from July 29 to Aug. 15, 1988.

Additionally, air-quality alerts are also in place for all of Southeastern Pennsylvania and the bulk of New Jersey.

The code orange alert says air pollution levels are unhealthy for sensitive groups. Environmental protection officials say the combination of sun, stagnant winds and lingering pollutant buildup are leading to high ozone levels.