What Were Those Horrifying Death Clouds Over NYC This Morning?

Dennis Mersereau · 09/30/14 12:57PM

Social media lit up around 7:30 this morning with hundreds of pictures of an incredibly dramatic sky over New York City, with layers of dark, intense clouds swirling over Manhattan. Clouds this ominous usually signal the approach of a horrible storm or Tammy Swanson. What kind of clouds were they?