Recognition and Impact of Vorticity Maxima and Minima in Satellite Imagery

• Introduction
  • What is Vorticity
• Vorticity Maxima
  • Overview
  • Physical Background
    • Development of a Comma Pattern
    • Morphology of a Comma Pattern
    • Other Considerations
  • Analysis
  • Interpretation
  • Implication
  • Exercise
• Vorticity Minima
  • Overview
  • Physical Background
    • Development of a Anticomma Pattern
    • Morphology of a Anticomma Pattern
    • Other Considerations
  • Analysis
  • Interpretation
  • Implication
  • Exercise

Vorticity Minima Exercise

The exercise of identifying vorticity minima is probably less interesting. Anticyclonic vorticity will mean calm weather and subsequently less interesting for the nowcasting period. Identifying minima on a satellite image can however prove to be harder as the circulation tends to be weaker, also you have to take into account that a correct analysis of the vorticity minima can help you to do a thorough model diagnosis and by this help you to do a better forecast.

To put this in perspective we present you with an example of 24 October 2009 at 1800UTC. You can toggle between the WV6.2 and the Airmass RGB. Starting from the initial image place the vorticity minima (N) and vorticity maxima (X) and draw with green pencil the deformation zones and with yellow pencil the position and orientation of the jet (optional). When you are ready click "next" to look at the ECMWF +18 hour forecast of the geopotential height at 300 hPa. With this overlay you may identify if the model is correct according to your analysis or you may choose to alter the positions of your X, N and deformation zones. When ready, again click "next" to get the following forecast field. At the end an expert analysis will show you the correct result to compare. Good luck and have fun!