Harmonic minor scale consists of ascending pattern:
WHWWH Aug2nd, H
The interval of the aug2nd between the 6th and 7th notes give this scale its characteristic exotic color.
C D Eb F G Ab B C
This scale is th first mode in the family of 7 modes, of which only the 5th, the spanish phrygian is commonluy used in jazz improvisation.
The notes in the harmonic minor scale maybe used whenimprovisnig over minor traids, minor (maj 7) chords, and minor 9 (major 7) chords.
Cm = C Eb G
Cm(Maj7) = C Eb G B
Cm9(Maj7) = C Eb G B D
The minor (major 7) chords consists of a minor traid with a major 7th added.
Adding a maj 9th to this chord creates a min 9 (maj 7) chord.
Typically, mino chords with a maj 7ths function as i or tonic chords in a minor key.
The 2nd and 7th notes in the harmonic minor sale are rich color tones when used over a minor chord.
The b6 is best used as a passing or neighbour tone to the 5th.
Melodic minor scale
The melodic minor has a different sequence of notes when ascending than when descending.
Ascending vesion also known as the jazzmelodic minor scale consists of the pattern:
WHWWWWH
C D Eb F G A B C
Melodic minor in ascending version
The scale is the first mode int he family that includes the dorian b2, lydian augmented, lydian dominant, Hindu or misolycian b13, locrian #2 and altered scaled.
You may think of the melodic minor scale as a dorian scale wth a major 7th or as a major scale with a minor 3rd.
Like the harmonic minor scale, this scale may also be used when improvising on minor triads, minor (major 7) chords and minor 9 (major 7) chords.
All the notes in the scale work well over these chords, with the 2nd, 6th and 7th degrees having the riches color.
Many players utilize the melodic tension created by the tritone that occus between the minor 3rd and the major 6th.