SEASON CHANGE

How does the meteorologist predict weather 7 days before and be so accurate? This snow has been predicted a week ago for Friday evening/night. 1-2 inches........Homecoming Football......lost..cold but no rain or snow and not really any wind. 1o:00pm.......we soon see a few flakes and a couple hours(as told to me) later it is difficult to see. This AM 2 inches of snow on the ground. So tell me how do they do this and be so accurate to when it starts and the amount? !!!?? Our picking season is over....two nights down to 23degrees. Suppose to be in the 60's this coming week. Maybe clean up fields and flower beds. Hopefully the weatherman is accurate with good days too??!? Suppose to be frost on the pumpkins not /*&##@!!!!