As we head into Autumn the large scale weather patterns
This morning, shortly after arriving at work I began to notice a few posts on my facebook wall feed regarding sun halos, thinking nothing of it I left the odd comment on how cool they are. Half an hour later, every second status was concerning sun halos, quite baffled at the sudden interest in atmospheric sciences taken by the general public I logged onto a news site to see what was going on. Turns out there was a 22` halo present around the sun in the Johannesburg and Pretoria area, and somehow it had made the news?!
For those that don’t know, halos are caused by reflectivity in the ice crystals in high level cirrus clouds, and for the Western Cape we see this happen prior to many cold fronts in the Autumn and Winter months as pre-frontal cirrus push in and create the common 22′ halo. It seems that while it is common place in the Cape, it’s far less common up country where the even caused the media to have an atmospheric field day. I understand that the reason for this is that the pre-frontal cirrus ahead of a cold front and the direct impact of a cold front is much more common to the Cape than up country, though I had no idea sun halos were considered rare there. Many residents claiming it is the first time they’ve seen anything like it.
So while all the Gauteng residents seem to think they have experienced something amazing, to those in the Cape- don’t feel left out. All you need to do is look for them ahead of cold fronts and you are bound to see quite a few each year. Granted the halo in Gauteng was quite strong and visible, you will be able to see quite a similar effect here in the Cape.
One or two of my 22′ sun halo pictures are located in : This gallery – though I don’t typically upload them due to how common they are.