Summertime convection

In the English language we have many words in common usage that have related but more specific meanings in a scientific and mathematical context. The key word of this blog post, “convergence”, is a good example of this. We sometimes hear of people’s views on some matter initially disagreeing and then, later, coming together or “converging”. In fluid dynamics we’re often interested in regions where different air flows come together. We call this type of flow convergence, and say that the air is converging. 

On Thursday 26 July 2012 a cold southeasterly airstream flowed onto the North Island, around an anticyclone centred just east of the South Island.
In this blog post we’ll look at some interesting small-scale cloud structures around the country on this day.
Below is the weather map at midday on Thursday 26 July. The red arrows show the sense of the broad-scale rotation around the anticyclone.