I thought readers might enjoy this photo. This frontal cloud formed from a northeast wind shift and lifting of humid ocean air enough to cool it below the dew point. The cold air acts a bit like the leading edge of an airplane wing. Taken about 5 miles offshore of Seaside Heights New Jersey, 8am May 14th, 2014
This photo was taken by commercial fishermen Michael Wark on his boat.
Click the image for a full sized view. Another example is seen below:
Frontal clouds, Uruguay