Lines and Swirls Explained

#2713 "Curly Hook Cirrus Sunset"
14x18 inches oils on canvas

As the world paves over paradise, may I suggest that you surround yourself with nature? The sky for doing so is the limit or so the saying goes. Actually, the sky has no limits for natural inspiration and perhaps I might be of some assistance. The sky is always available and all you need is time. 

Start by watching the patterns move across the sky. The translation of the clouds does not have to impact the shapes. The average wind simply moves the clouds along. Without water vapour, the circulations are quite invisible but they are still there.  

Recall that moisture is shaped by relative motions within the atmospheric frame of reference. I have written about this many times but "Down to Earth Meteorology" is a good summary.  Absolute location to another reference frame such as the Earth only makes the patterns harder to comprehend. The shapes reveal the wind and those patterns are readily understandable in terms of lines and swirls. The answer is indeed blowing in the wind. Bob Dylan’s 1962 anthem posed some rhetorical questions about peace, war, and freedom and sixty years later, those elusive dreams have still not been attained. In the example of the atmospheric frame of reference, there is a solution though. All patterns within the atmospheric ocean evolve from that simple puff of wind along with smoke rings. 

I reiterated the foundation for this work in my previous blog, “A Jet Streak with a Paddle”. This current blog will assemble those parts in terms of lines and swirls. I will follow that with the easiest atmospheric example - mare’s tail cirrus.  After that, you are ready to understand every cloud in the free atmosphere – almost anyway. 

The Deformation Zone Conceptual Model complete with
Coriolis Hand Orientations - for reference looking down

In “A Jet Streak with a Paddle” we established:

• The col of the deformation zone (DZ) is located where the rate of speed increase or decrease is the strongest. 
• The deformation zone (DZ) associated with a speed increase must parallel the flow.
• The deformation zone (DZ) in an area of speed decrease must be perpendicular to the flow.

Looking Down as in a Satellite View

The Swirls of the Deformation Zone Conceptual Model 
can be added to the lines. You cannot have lines
without the swirls

Smoke Rings are the Three-Dimensional Manifestation
of the Local Wind Maximum. The Visible Smoke Ring
related to the Companion Swirls associated with the 
wind maximum

Cirrus cloud is almost always in the sky for our entertainment. Cirrus is much more exciting than most meteorologists give it credit for. This post and “A Jet Streak with a Paddle” will allow you to understand what the lofty cirrus has to say.

Cirrus uncinus is a special type of cirrus cloud. The word "uncinus" is derived from Latin, meaning "curly hooks". Also known as mares' tails, these clouds are generally sparse in the sky and very thin. The clouds occur at high altitudes, at a temperature of about −50 to −40 °C. They are generally seen when a warm or occluded front is approaching. They are also shaped by the relative wind!

The curl at the end of the band of cloud is associated with a decrease in wind speed. Within the atmospheric frame of reference, a decreasing wind speed requires deformation zones perpendicular to the direction of the flow. 

Looking Downward on the Curly Hook Cirrus Pattern

In order for the speed to decrease, somewhere upstream the wind must have increased in speed as compared to the average flow of the atmosphere. If the speed of the flow increases, the deformation zones must parallel the direction of the flow. The fingers of your Coriolis Hand when aligned with the curl of the cloud, reveals if the moisture is associated with the cyclonic or anticyclonic companions of the atmospheric flow. 

Typically moisture is found on the warm side of the jet stream. This corresponds to the anticyclonic companion. You might notice that the majority of the mare’s tails are anticyclonic swirls. The wind decreases at the end of each mare’s tail necessitating the axis of the deformation to align perpendicular to the flow.

Painting Looking Upward

You can also monitor the drift of the cloud by the average wind. Using your Coriolis Hand, you can determine if the drift relative to the average wind is either cyclonic or anticyclonic. Point the fingers of your Coriolis hand in the direction of the drift as you watch the approaching cloud.  If the drift is toward your left, your Coriolis thumb points downward and you are watching the anticyclonic companion of the deforming flow.  If the drift is toward your right, your Coriolis thumb points upward and the cyclonic companion is headed your way. Your right hand is your Coriolis Hand in the northern hemisphere. This is another application of the deformation zone conceptual model when the wind aloft is decreasing in speed. If there is no lateral drift in the cloud patterns, then the wind is increasing over you. I wrote about the Coriolis effect in "The Solution to Cloud Swirls Can Be Found in Your Hands". 

Everything begins with a change in wind speed. Everything! The change in wind speed results from a change in temperature which in turn drives the thermal wind which directly results in variations in wind speed. Meteorologists call this wind shear. Wind shear creates deformation zones and vortices but you can call them lines and swirls. It's OK, I do. 

Summary of the Lines and Swirls with a "Wind Maximum"
or Paddle Stroke complete with the orientation of your
Coriolis Hand revealing the sense of rotation remembering
of course that the circulation is really a 3D Smoke Ring in space
Looking Downward

Indeed, the entire Conveyor Belt Conceptual Model can be explained using these simple concepts. The infra-red satellite imagery was "fuzzy" in the 1980s but was still adequate to convince me of these truths based on my experience with the paddle. My artistic background was conducive to revealing the patterns I witnessed in the lake and translating them to what I saw in satellite imagery and the atmospheric ocean. The boundaries between air masses are more than just lines, they are deformation zones. 

There is only one thing you need to know - the local wind maximum is responsible for everything you will see in the sky. The wind maximum can be as large as a jet streak in the jet stream or as small as a gust of wind. All patterns in the free atmosphere can be explained by the local wind maximum which creates nested patterns of lines and swirls.

With thanks to my friend Dr. James Moore and
COMET who published many of my
meteorological musings. 

Warmest regards and keep your paddle in the water,

Phil the Forecaster Chadwick