Erica's Answer:
The suburbs of the city are 300-400ft higher in elevation than the airport, which is near sea level. That's why we often use the city line as the line of demarcation between areas of wintry precipitation. However, most of Chestnut Hill, Roxborough and Andorra are a few hundred feet above sea level, so people who live in those neighborhoods of Philadelphia should expect to have similar weather conditions to the immediate suburbs of the city, such as Ardmore or Trevose.- Erica
