Forecasters: August's first 90-degree day expected Wednesday

Forecasters say the temperature in Philadelphia is expected to hit 90 degrees tomorrow -- for the first time this August.

The month so far hasn't seen a single a day with the mercury in the 90s. But the National Weather Service is calling for a high temperature Wednesday of 90 degrees, 5 degrees above the normal high for the date.

The hottest day of the month was Aug. 9, when the temperature topped out at 88 degrees. Philadelphia hasn't seen a 90-plus day since July 21, when the mercury hit 91, according to the National Weather Service.

This August has been cooler than normal.

The overall temperature in Philadelphia this month has averaged 73.7 degrees, 3.8 degrees below normal, according to the weather service. The high temperature has averaged just 80.8 degrees, nearly 5 degrees below the normal of 85.3.

Philadelphia typically sees six to seven days in August with temperatures of 90 degrees or above. Last year, there were eight 90-plus days, and there were four such days in August 2011. 

This July, the temperature hit the 90s on 12 days.

Along with the warmer-than-usual expected temperature, air quality alerts have been issued for the Philadelphia area and South Jersey for Wednesday.

The code orange alert means air pollution concentrations could be unhealthy for sensitive groups, like the elderly, children and those who suffer from asthma or heart and lung diseases.

Thursday is expected to remain warm, with an expected high of 88 degrees, forecasters say.

Friday, Saturday and Sunday are all expected to see lower temperatures, with forecasted highs of 84, 80 and 81 degrees.

Contact Emily Babay at 215-854-2153 or Follow @emilybabay on Twitter.

Contact the Breaking News Desk at 215-854-2443; Follow @phillynews on Twitter.