Weather Lessons for Everyone from the Cold Conveyor Belt Wizard

#0505 "Ominous

The meteorological journey to get to this point started nine months ago. Some of the science steps were absolutely essential to justify the observations we are about to assert. Some strides were more for background, nice to know information. But where are we after this gestation period of these meteorological concepts?

The cold conveyor belt (CCB blue arrow) holds lessons that the can teach everyone. We have already established how the cold conveyor belt can control the phase of the precipitation in some surprising ways. The cold conveyor belt can also reveal the characteristics of the entire mid-latitude storm through the Conveyor Belt Conceptual Model and the Weather Machine. Here is how that wizard works.

The premise is that a warm conveyor belt and storm is approaching your region. You are located within or under the Cold Conveyor Belt. This is what you observe:

The surface wind (the cold conveyor belt as measured in the earth frame of reference) has a westerly component. I used the large green arrow in the graphic to depict the surface wind result of the vector addition. This is the typical mid latitude storm that is moving steadily with the jet stream across the landscape. Cirrostratus arrives on the western horizon but the surface winds stay out of the southwest. The system crosses the area without hesitation. The precipitation, if there is any, comes and goes quickly. Stronger westerly winds signal the passage of the cold front and the system. The speed of the system relative to the earth (purple arrow) is faster than the atmospheric frame winds in the cold conveyor belt (blue arrow). The vector addition of these winds leaves a surface wind with a westerly component - the green arrow in the graphic.

The surface wind (the cold conveyor belt measured in the earth frame of reference) is calm. The mid latitude storm that is moving a bit slower across the landscape. Cirrostratus arrives on the western horizon and the surface winds gradually decrease in speed. The cirrus is slow to thicken up into altostratus.  The precipitation, if there is any, will arrive slower and last a bit longer. The calm winds will shift to the west with the passage of the cold front and the system. The speed of the system relative to the earth is about equal to the winds in the cold conveyor belt so that the vector addition of these purple and blue arrow winds balances out to provide the "calm before the storm".

The surface wind (the cold conveyor belt measured in the earth frame of reference) has an easterly component. The mid latitude storm is moving slowly across the landscape. Cirrostratus arrives on the western horizon and the surface winds gradually increase from the east. The cirrus is really slow to thicken up into altostratus.  The precipitation, if there is any, will arrive very slowly and last much longer. The easterly winds will shift to the west when the cold front arrives - but the storm is likely to last a while. The speed of the system relative to the earth (purple arrow) is slower than the winds in the cold conveyor belt (blue arrow) so that the vector addition of these winds generates surface winds out of the east – which are never good for man or beast.

In the previous three examples only the speed of the system was adjusted to arrive at the different evaluations of the storm. The strength of the wind in the conveyor belt system can also be adjusted. For example as the storm intensifies, the conveyor belt winds in the weather machine will also increase with speed. The effects of this can be evaluated by observing the results at the surface within the cold conveyor belt.

A fast moving system that still produces an easterly cold conveyor belt wind at the surface is a very strong storm indeed. It may cross the region quickly but the strength of the circulations will make it a force to be reckoned with. In general, the stronger the easterly surface winds in the cold conveyor belt, the more likely that the storm will last longer and probably be more intense as well.

By observing the surface wind in the cold conveyor belt portion of the storm, a keen observer can estimate how fast the system will cross their region as well as the intensity of the storm. If the observers also remember how to read the lines in the sky and have their right fingers handy, then they might also deduce which portion of the warm conveyor belt is likely to cross their position.

A Closer Look at Lines in the Sky 

Observing Warm Conveyor Belts and Forecasting Your Own Weather 

It took almost nine months to carefully establish the linkages between observing the surface wind to really understanding the weather. The pioneers had it figured out by observational trial and error. Their crops and lives depended on it. They recorded their findings in rhymes. Their weather poems and ditties would fill several books.

Personally, my meteorological training was much more book based. My university background was theoretical physics with an emphasis on nuclear. Back in 1976 I needed to pass a crash course in meteorology in order to stay employed with the then Atmospheric Environment Service of Canada. Fine academic textbooks on meteorology  (James R. Holton comes to mind) did not prepare me for the real world though. Happily, my plein air painting and the arrival of remote sensing did. I spent all of my career trying to really understand the weather from a more personal and natural perspective more akin to that of the pioneers.

Environment-based education is a current movement trying to reconnect students with the natural world. That is the unstated goal of my Art and Science Blog. The timing to present this material during COVID-19 was intentional. Observations of the natural world and the Cold Conveyor Belt in this example, can teach a lot. Technology and tablets may be glitzy but nature is real. Immersing yourself in the environment along with nature is where you can really begin to learn and to live. I would like to suggest some reading. The Last Child in the Woods and the Nature Principle by Richard Louv would be a good place to start.

Warmest regards and keep your paddle in the water,
Phil the Forecaster

PS: The real weather is always more complicated but these conceptual models will help you figure that out…