January 29, 2004
It's not exactly clear just what type of cloud this interesting photo shows. However, without doing a lot of "forensic meteorology," it appears that it's either a form of wave cloud or an expression of the jet stream. The photo was taken in June (about 30 miles or 48 km north of Toronto), when the core of the polar jet is normally displaced northward into Canada. Linear cloud formations like this are sometimes observed oriented parallel to, and embedded within, the axis of the jet stream. If the upper flow was zonal (west to east), then you could expect these banded features to be oriented as shown on the picture. Note that the sky to either side of this anomalous cloud was generally clear, with a few clouds floating by. These clouds were not traveling in the same direction as the dramatic, linear cloud but rather moving from southwest to northeast.