The melodic minor scale is a very expressive sad scale which can be used to create nostalgic sense and add some sorrowful vibes. It is a scale that consists of seven notes and is often used in jazz, classical, metal, rock and folk music. This scale can be used to create interesting chord progressions, melodies, and harmonies. By understanding the melodic minor scale and how it works, composers can unlock new possibilities when it comes to creating their own music.
It pattern has 2 forms - different for ascend and descent.
Tonal ascending has the following steps from the root note: W h W W W W h
It descends in a different way like this: W W h W W h W
W for whole step and h for half step
So actually while ascending is same as Aeolian mode (natural minor scale) but with 6th and 7th raised on semitone.
While descending it reforms and now it is exactly the same as Aeolian.
Generally it is used for creating nice variation in feelings - in a sad way. It also carries a nostalgic hopeful feeling while ascending making this scale a unique music path to experiment with.