Disturbance four deepening and set for Caribbean Islands
General overview Tuesday 18th August 2015
An area of non-tropical low pressure is forming near Bermuda and may develop slowly over the next few days. This is initially expected to drift to the south-east before tracking to the north-east. Development chances are very slight but one or two keen observers are watching this as it may develop onto a subtropical system and brush the north-eastern seaboard towards maritime Canada but is more likely to remain over open water.
Disturbance twenty-eight has been the weatherman's centrefold since it charged off the African coast with a determined twinkle in its eye and has begun to cause some excitement. Now upgraded to tropical depression four and currently centred 1500 miles due east of Barbados, the system is headed a little north of west at 10 knots with winds between 35 and 45 knots. At the moment, the windfield visible from aerial imagery is around 80 miles radius.
Aerial imagery shows some clearly defined surface circulation and sea surface temperatures in the locality are above average, which will assist in setting up a vertical circulation column. As this is fairly slow moving, our view is that this will reach tropical storm status soon. One or two of the more enthusiastic commentators are already predicting this to become a category one hurricane but this is far from a consensus. As things stand now, this would reach the islands of the east Caribbean in six to seven days time. Nonetheless, upper level wind shear still awaits in the southern Caribbean which may prevent this having any impact further west, however this will not cut in before the cyclone reaches the Caribbean.
A new disturbance looks set to emerge off the coast of West Africa in a day or two and join the westbound trek. Conditions across the intertropical convergence zone are becoming less hostile for cyclonic development so this is also one to watch.