Kylesa - Static Tensions
Album came out 2 days ago but it's been leaked online for quite some time now. They're a psychedelic proggy metal band with occasionally heavy riffs. A bit like Isis but with shorter and much less coma inducing tracks.
Intronaut - Prehistocrisms
Their last effort falls a month short of your 6 month requirement but it's worth the mention. They play experimental prog metal with a lot of jazz and sludge influences. Incredible bass lines. Consciously written and well played.
Yeah Yeah Yeahs - It's Blitz
Awesome album from an awesome band that really doesn't need a description. Since you're a Metric fan they're probably more up your alley than the last two.
I should also add that all of the bands I've recommended are currently on tour.