Observing Warm Conveyor Belts and Forecasting Your Own Weather

#1717 "Sunset Waves Nite" Pixels Link

This is the last post on the warm conveyor belt before we move on to the dry conveyor belt. Exciting times for sure! The goal is to figure out just what part of the storm is about to pass your location. The warm conveyor belt is the most visible part of that storm and provides the answer. You can do this!

To become an armchair forecaster, first position yourself to look southwestward... more or less. Most warm conveyor belts approach from the southwest more or less, at least over southern Ontario. If you wish to be more exact, note the current orientation of the jet stream over your location and use that portion of the flow that lines up with the warm conveyor belt. Turn your armchair to look into the jet stream. The jet stream guides the storms and the warm conveyor belt and is the purple line in the accompanying graphic.

Apply these tips to deduce the atmospheric frame winds.

• The deformation zone has a characteristic orientation to the winds in the atmospheric frame of reference – regardless of the spatial scale of the deformation zone. If you are looking into the col, you are looking into the wind. See A Closer Look at Lines in the Sky.
•  Langmuir streaks parallel the atmospheric frame of reference winds – even though they might look like they diverge similar to crepuscular rays and train tracks… see Langmuir Streaks 
• Gravity waves your best friend and are everywhere perpendicular to the atmospheric frame of reference winds. The spacing of the gravity waves varies directly with the speed of those winds. The waves also drift in the same direction as the generating winds just like waves on a lake.

Armchair Weather Observation Platform

Now is the really fun part! You need to sit in the armchair looking directly into the approaching warm conveyor belt. Identify a characteristic piece of cloud that you hope to follow for a few minutes. 

Line that piece of cloud up with the window frame or something not moving and watch which way it drifts. In a few moments you should be able to tell which way that cloud is moving relative to your earthly vantage. Since you are already looking into the warm conveyor belt and the approaching storm, you are looking at mainly the motion of the cloud due to winds in the atmospheric frame of reference. 

If that cloud piece is moving to your right ... the cyclonic companion of the warm conveyor belt is approaching. Point the thumb of your right hand upward and see if your fingers align with any of the swirls in the cloud. There could be gravity waves in the cloud perpendicular to your fingers and the atmospheric frame winds. There should also be a considerable amount of cloud. See The Cyclonic Side of Life for more details. 

If the characteristic cloud is moving to your left, the anticyclonic companion is in line with your location. Point the thumb of your right hand downward and see if your fingers align with any of the swirls in the cloud. Gravity waves are likely in any cloud that might be present. There may not be much cloud as well and that is part of the clue. See The Relativity of the Companion Flows in the Warm Conveyor Belt for a look at the anticyclonic companion. 

If the cloud is not moving appreciably either to the right or left, you are looking directly at the col in the deformation zone. Lucky you! If there is no delta void in the cloud on the warm side of the deformation zone, then the companion vortices are less intense than average. As the companion swirls increase their spin speed with a corresponding increase in the velocity of the winds in the warm conveyor belt, moisture is increasingly spun away from the col. The delta shape becomes progressively void of moisture - another important clue to the wind speeds in the warm conveyor belt. These winds bring the heat and moisture energy to fuel the storm.  

It is typical with the approach of the warm conveyor belt that the conveyor belt pattern will continue to move along with the jet stream. You may initially see the cyclonic companion but if the storm is far away, the col and eventually the anticyclonic companion could be what you actually receive as weather when the storm eventually arrives. You will need to repeat this exercise as the storm progresses. It will mean sitting and watching the sky. I know you can do this…

You can also enjoy a satellite view of the patterns if you get tired of looking out your window. I prefer a site created by my friends at UCAR (University Corporation for Atmospheric Research) in Boulder, Colorado. Simply Google “UCAR Real Time Weather” and select the mid-level water vapour image for best results. http://weather.rap.ucar.edu/satellite/  If you follow the storm in an animation, your brain and eye will automatically focus on the relative motions of the cloud features that are created in the atmospheric frame of reference. 

Weather is important and it can also be fun! Enjoy the weather when it arrives ... evaluate your prediction (this is also called performance measurement). Have fun and learn... repeat this exercise daily. Embrace nature... it is very good for both you... and nature. 

In #1717 "Sunset Waves Nite" I recorded the leading edge of the anticyclonic companion in oils. Art and science merge. 

Warmest regards and keep your paddle in the water,

Phil the Forecaster

PS: There is no crime in updating, revising, amending or rewriting any forecast based on new observations when they become available. Doing so just indicates that there is still something to learn from nature and that your goal is to better serve your clients. :>)) Anyone who has never fixed a forecast, has yet to really write one that said something worthwhile and of potential benefit to the client. Thank you for reading and getting this far...