The Mother's Note can be found inside a child's lunchbox next to a post at the northwest corner of Lansdale Avenue and Brite Street (near the Pearl Creek Bank) in Pearl Creek in Silent Hill: Downpour. This note is related to the "Ribbons"sidequest where the player must use the two different colored ribbons (yellow and red) which are tied around street lights in order to try and locate the missing little girl; Ariadne Johnson.
Mommy has made a new path for you to follow home. Remember the rules...
Yellow Ribbon = Turn Left
Red Ribbon = Turn Right
I know you sometimes get confused, so just be a big girl and look for mommy's ribbons and you'll be fine. Whatever you do, DON'T BREAK THE RULES! Mommy will be waiting for you at home.