UPDATE Invest 90L has been deactivated due to the circulation
Currently there are a few features that I am looking at with interest, but first I’d like to touch on an exciting event for those of us in Cape Town, we had our first decent thunderstorms in almost a year. On Monday the 6th of February 2012 Cape Town received some pretty awesome little thunderstorms, What made them awesome wasn’t the fact that they were severe, because they were nothing close to being severe, but rather the nature of the cloud structures. During Cape thunderstorms you will typically see a blanket layer of altocumulus with some embedded cumulonimbus, definitely not the best for photography purposes.
On Monday 6 February though, there were some beautiful isolated cumulonimbus cells visible. I woke up at around 6:15 to a bang of thunder, I had been texted the previous night by Gordon Richardson who had notified me as to the possibilities existing for thunderstorms but conditions looked marginal at best on the models and I didn’t think too much of it. After being woken I grabbed my camera and car keys and headed out to see if there was anything worth shooting, I first headed up to the Helderberg Nature Reserve looking east, where a large cell was almost directly over me, but not great for photos. I then drove a few kilometers to the top of Irene Avenue which offers a pretty clear view of False Bay and the view was much better there with a couple of cumulonimbus cells visible, one of which had weak mammatus on the eastern end of its anvil. Before I knew it, it was time to head to work, but definitely worth getting up.
Later that evening I headed to Strand beach in the hopes of a good sunset and possible some evening lightning, I managed to succeed on the former, but no luck on the lightning. Regardless, it was an enjoyable days weather in the Cape. Temperatures still rose to the 30s in the day time though, with the humidity quite high.
Looking ahead, we have a cut-off low approaching from the west this week which is set to bring unseasonably cold weather to the Cape with temperatures dropping around Cape to below 20’C. Usually around this time of the year, these cut-off lows don’t bring such cold air with them and sometimes bring thunderstorms to the area, this looks to be more of a ‘winter in summer’ event though, with large swells likely along the south coast into the weekend.
The low pressure itself is actually forecast to remain off-shore as is often the case and slide south of South Africa, though it’s effects are likely to be felt. Cut-off lows are very vulnerable to change and a small shift in the synoptic pattern can change a forecast dramatically. Light rain looks like a possibility from late Friday into Sunday, with the largest chance being on Saturday as per the latest model runs.