Update: A July 19, 2013 Globe and Mail article highlights photos from the July 19, 2013. [End of update]
Mammatus clouds are described as “pouch-like cloud structures and a rare example of clouds in sinking air” (see link at the beginning of this sentence).
I learned about them at Twitter when many people were posting mammatus photos.
Below are mammatus clouds photographed in Long Branch (Toronto not New Jersey) after a recent evening thunderstorm on July 19, 2013. The next photo is from later the same evening when a different form of cloud structure appeared.
I bracketed the exposures for each image and then chose the ones that worked the best.
@SarahChauncey of Nanaimo, B.C. shared the following Tweet regarding mammatus clouds:
“Not so rare out here any more (they’ve become more frequent over the past few years). Surreal: Snowflakes when it’s 15C.”