On the heels of the coolest highs seen in the area since mid-June, overnight temperatures dipped into the low 50s in the suburbs, even the 40s in the Poconos, flirting with records.
The 62 degrees recorded at Philadelphia International Airport about 6 a.m. was the lowest mark since June 16, though still above the record low for July 30 of 58.
Other area temperatures reported around that time were 50 in Quakertown, 53 in Pottstown and Allentown (where the record is 50), 54 in Blue Bell, Doylestown, Millville and Lancaster. Hazleton and Mount Pocono hit the mid 40s, according to the National Weather Service in Mount Holly.
Tuesday's high at the airport was 76, the coolest for any date since June 14.
"A large southward dip in the jet stream, also known as a trough, has pumped in cool air from Canada into much of the central and eastern U.S.," according to weather.com. "Forecast high temperatures will be as much as 25 degrees below average for this time of year in some areas," though less so in the East.
Today should be quite a comfortable day, with low humidity and a high in the low 80s under fair skies. Temperatures should again dip into the mid 60s overnight, then warm a bit toward the weekend, hitting highs in the mid 80s Thursday and Friday, with lows in the upper 60s.
Threats of rain increase toward the weekend, with a 20 percent chance of showers Thursday afternoon, a 40 percent chance of rain with possible thunderstorms on Friday, and a 50 percent chance of showers Saturday and Sunday, according to the National Weather Service.
For more on the forecast, go to John Bolaris' weather page.