Amazing weather system off Tanzania

[whipper_snapper]

Between Christmas and New Year we did some sailing around the Kenya and Tanzanian coast. We successfully dodged the pirates and had a great time. I took some video with my new xacti as recommended by Dylan. I will try to assemble some sort of video just to make you all jealous in mid UK winter.

BUT. Just to show it isn't all sunshine and force 4 with jumping fish and cold beers (but mostly), I quickly hacked together a video showing a huge weather system that appeared from nowhere. I don't really understand tropical weather, apart from hardcore systems like TRSs, weather seems to 'bubble up' from nowhere and is almost impossible to predict. This huge system appeared within a few minutes. Ten minutes after we saw it, it arrived and winds went from 7kn to 35kn in seconds with driving horizontal rain. It was no real concern and some fresh water sluicing was nice. But at night with zero warning and full sail it could have been dangerous.

I would be interested in comments from any weather experts....

 

[Sybarite]

Line squall?

 

[Old Troll]

Old Troll

Hi and trust you are enjoying your Tanzanian sail. There are some wonderfull anchorages and Safari lager to be enjoyed if you stop off. The people are also very hospitable. On your video you show these dark, intense and low lying clouds gathering over the sea. In my experience these features could on occasion gather into little tornadoes or twisters and give the weather conditions that you describe. These twisters can be seen coming during day light hours or in the moonlight which enables one to stand by for the wind and rain. Fortunately they passed quickly although very intense over a small area. Not unlike seeing the white squall heading your way on west coast of Scotland. If the twisters came ashore they could blow away huts and trees etc. The hot and very humid atmosphere appeared tp fuel the rain squall and start the spin effect. I worked the Tanzanian coast between Zanzibar and Cape Delgado for some years. A world class sailing area and coast. Good Sailing.

 

[whipper_snapper]

Thanks, yes it is awesome cruising. Anchoring over a reef and snorkeling in crystal clear water 5 miles from the nearest land is pretty cool!

WRT to my own comments about encountering such stuff in the dark. We don't have a barometer on board but I wonder what happened to atmospheric pressure as it developed and approached and if that would have provided a warning.......

 

[Old Troll]

Old Troll

As we operated our fisheries survey from a 8.5 metre open motor/sail boat there was no access to having a barometer. In hindsight it would have been interesting to have kept a record of such readings. At night the wind would drop until calm arround midnight. Is that your experience?

 

[sarabande]

isn't that an example of explosive cyclogenesis ?

http://www.eots.co.uk/reports/bomb/bomb01.htm


If it is, you owe my colleague, Lady Campanula, a virtual beer. EC was a subject we discussed over the holidays because a small one fell on me while I was hedging.