Yea good shot of the sky. I agree with John it comes across as too dark. Try cropping out some of the black foreground. That will make the sky more prominent and should make the shot appear to be lighter.
Welcome to the forum! Great shot! Glad you jumped right in with posting a pic! As you can see, this forum has a lot of expertise and good will . . . happy shooting and enjoy!
Best Regards from the southwest (and from someone who was raised in Philadelphia!)