If you hear the sound of the wail, then such dream shows that you will suffer because of the bad news. The wail that is made by the police, signifies problems with regulations for your close people.
Dream dictionary: Wail dream meanings
…A wail falling upon your ear while in the midst of a dream, brings fearful news of disaster and woe. For a young woman to hear a wail, foretells that she will be deserted and left alone in distress, and perchance disgrace. See Weeping….
To hear a wail, when you are dreaming, has meaning of sadness and pain in those who are around you. If you are wailing in the dream, then it may signalize that you can freely release sad emotions. Anything that may not be appropriate in your waking life can be eliminated easily.
If you heard the wail in a dream, then it denotes to the sorrow and sadness you will suffer. To dream of yourself wailing, denotes to the emotions you have released during your sleep. Perhaps you were holding the negative emotions and the unconscious mind of yours have released it.