This one also sets your focus, if you don’t need that aspect of it you can go simpler.
#showtooltip
/focus [mod:shift,@focus,dead] [mod:shift,@focus,noexists]
/clearfocus [@focus,dead] [mod:shift,@focus,noexists]
/cast [mod:alt] Howl of Terror(Rank 2); [mod:shift,@focus,harm,nodead] [@mouseover,harm,nodead] [] Fear(Rank 3)
Without focus management:
#showtooltip
/cast [mod:alt] Howl of Terror(Rank 2); [mod:shift,@focus,harm,nodead] [@mouseover,harm,nodead] [] Fear(Rank 3)
Keybinds take priority over macro modifiers. By default SHIFT 1-6 are bound to Action Page 1-6. If you want to use them in macros you’ll need to unbind those keys.