In the Philadelphia area in the 1980s, snow closures were not announced on radio stations by name. Each school (or school district) was assigned a 3- or 4-digit number. On "snow days," radio stations would read a list of the numbers of the schools that were closed (or delayed openings, or "no transportation").
Penn Charter School, the school William Penn Academy is based on, is 122. Jenkintown School District is 400.
When Adam and Barry were apparently trying to push Murray out of the snow fort, it is clear as day he is not stuck as there is at least an inch of daylight to his left.
After Barry returns from pulling Adam on the sled with the car, palm trees can be seen briefly above the roof of the house. Palm trees don't grow in Pennsylvania - and certainly not where it snows. Snow in this episode is obviously fake (fully green trees can be seen in some shots).