Update 20 September: It was only in the last few days that we had a yellow alert for rain, and now again rain is forecast. Aemet says that Tenerife is likely to the most affected of the Canaries with stormy conditions from this Tuesday afternoon, with rain which could be torrential in parts. As always, this forecast is likely to become clearer over the next few days.
Original post 17 September: The Met Office Aemet has issued a yellow alert for rain tomorrow in Tenerife. The alert applies to all the western islands and Gran Canaria between 6am tomorrow and midnight Friday/Saturday, and forecasts rain of up to 15mm an hour. The mainland has been suffering with the first real storms of autumn over the last 48 hours or so, and the lower end of the system bringing that weather in from the Atlantic is what will reach us in the Canaries. At the moment, the front is south of Madeira.