#2293 "Georgian Bay Cloud Stories"

The weather is written in the clouds if you know the vocabulary. The shapes of clouds in the free atmosphere well above any interactions with the earth are all the result of changes in the relative wind speed and direction - within the atmospheric frame of reference. Clouds may move along with the average wind but the shapes are all carved by slight variations in this average. Swirls and twirls are the result of the weather dance and the lines are all deformation zones. Weather is more of a ballet than a battle.

Circulations in the atmosphere are very three dimensional. The deformation zone that I often refer to as a line as illustrated by the double headed green arrow is really just a cross-section through the three dimensional deformation skin. Moisture tends to be on one side or the other of this atmospheric barrier. The shape of this deformation zone reveals the relative intensity of the vorticity swirls on either side of it.

The three dimensional circulations are exactly like smoke rings driven by a relative puff of wind. Since clouds are quasi horizontal in nature, they only reveal the opposing cross-sections of these smoke rings. The rest of the smoke ring is only revealed in your imagination. If you follow the smoke ring with your ring hand the curl of your fingers are in the same direction as the swirls of the smoke ring. If your thumb is point upward meteorologists refer to that area as positive vorticity and a red "X".  If your thumb is point down that is negative vorticity depicted as a blue "N". The truth is that the circulation is a single three dimensional circulation.

Some people better visualize the three dimensional deformation zone skin as a jellyfish. Both the jelly and the ocean are fluids just like the atmosphere. I tend to think that the jellyfish propels itself through the ocean by first creating the ring of vorticity on its outer edges. The watery version of the smoke ring in turn creates the puff of relative current in the middle that moves the jellyfish forward. In the smoke ring analogy the puff from the smoker comes first which then generates the ring of vorticity. In the jellyfish the vorticity ring is created first. The reality is that the relative wind or current maximum must also have the ring of vorticity associated with it. You cannot have one without the other.

Any cross-section through the three dimensional deformation zone skin results in a deformation zone line which one can easily draw on a flat piece of paper. The shape of this deformation zone line reveals everything about the associated swirls which are in turn just cross-sections through the three dimensional vorticity ring. Deformation zones come in three flavours as I have sketched. This is the kind of stuff I have been describing during my meteorological career. Art is really just science and vice versa.

In this particular sky the deformation zone patterns of the large rotational patterns are still evident in the warm conveyor belt. On closer inspection there are many interesting smaller swirls within the larger display as well. Rain was on the way with this warm conveyor belt. Weather is always fun to paint and it is a challenge as well.

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