Bad Writing Score - Will it affect my composite?

I got a 33 composite on the April 2015 ACT (36 E, 33 M, 31 R, 30 S), which I was pretty happy with. However, I got just an 8 on the writing test, bringing my combined E/W to a 32. Does this take away from my 33 composite? I am highly considering applying to Northwestern early decision next year, if you’re wondering if I might have any specific schools in mind.