Philadelphia started Wednesday, August 5, under mostly cloudy skies and around 75 degrees, with a sticky feel already in the air. The city is headed for a high near 85, but the bigger story is a day that begins with scattered showers and ends with a much better chance of thunderstorms.
Showers may pop up around 10 a.m., with thunderstorms becoming more likely from early afternoon through early evening. The National Weather Service says a warm front and weak low-pressure system are crossing the region, raising the risk of heavy rain, localized flash flooding and, in a few storms, damaging winds; there is a marginal risk for excessive rainfall.
Storm Chances Rise After Lunch
Rain chances rise from about 20% late morning to 40% around midafternoon, then peak near 70% from 4 to 6 p.m. Most spots could pick up a tenth to a quarter-inch, but storms that repeatedly cross the same neighborhoods could produce more than an inch in a short time.
Tonight stays warm and humid, with a low around 73 and another chance of showers or thunderstorms before 4 a.m. No watches, warnings or advisories are listed for Philadelphia in the current forecast, but a downpour can still quickly create problems on low-lying streets.
Thursday Brings The Heat
Thursday is mostly sunny and hotter, with a high near 91 and heat index values as high as 103. A slight chance of storms returns after 4 p.m., followed by more storm chances Thursday night.
Hot, Humid Pattern Lingers
Friday should reach 91, Saturday 90 and Sunday 90, with afternoon or evening storm chances Friday and Saturday before a mostly sunny Sunday. Monday may be the hottest day of the stretch at 92, while Tuesday stays near 91 with another afternoon storm chance.
Plan Around The Heat And Heavy Rain
For outdoor plans Wednesday, the safest window is the morning before storm chances build, though conditions could change quickly. Philadelphia's heat-safety guidance recommends drinking water, taking breaks in cooler places and avoiding strenuous activity during the hottest part of the day, especially as Thursday's heat index climbs.
