A nor'easter announces itself over the Weston line as a low grey seam, then arrives sideways and wet, the kind of snow that weighs three times what it looks like. Norfolk Tree Service, LLC meets it with plows, shovels and salt — driveways, lots, walkways, entries — and circles back as the storm keeps re-covering the work. Waltham's older streets narrow quickly once the banks build, so passes get planned to leave room for cars and mailboxes both. Bare pavement by morning is not glamorous, but it is the entire job, and it feels good to get it right. Snow clearing in Waltham, Weston, Wellesley, Newton and Lincoln.