From west to east:
Today’s single stroller Disturbance Eight is seaborne but has not progressed in organisation overnight from the weak trough we picked up over the mouth of the Mississippi yesterday. Currently loosely centred 150 miles south of the Louisiana coast and drifting aimlessly west, this is defined only by an increase in localised thunderstorm activity. This will push slowly to the south-west over the next day or two towards the lower Texas coast. Conditions remain marginally favourable for some development before it moves inland across south Texas overnight on Wednesday as a tropical depression or weak tropical storm. Slow ground speed will allow this to pick up biblical quantities of moisture and this will produce very heavy rainfall for parts of the Texas coast this week.
The remainder of the field consists of low pressure cells moving at an uncharacteristically fast speed. Disturbance Five is centred around 100 miles north of the coast of Colombia moving west at a brisk 23 knots. A high ground speed has shredded the convection column and will prevent development beyond heavy showers and thunderstorm activity as it heads for a landfall overnight tomorrow in central America.
Disturbance Six is currently 400 miles east by south of Trinidad, tracking west-nor’west at a sprightly 22 knots. Despite the ground speed being one which would normally inhibit organisation, aerial images of the wide field of thunderstorms around the nominal centre are showing signs of determined development. An expected deceleration over the next few hours may allow this to become a named tropical storm before reaching Trinidad tonight. Regardless of development, it will bring muck and filth to Trinidad, Tobago, and the Windward Islands later today with heavy rainfall and some lusty squalls. Environmental conditions once inside the Caribbean are likely to be ripe for this to develop further and there are already one or two (credible) observers discussing hurricane force winds once it passes the Netherlands Antilles and makes a beeline for the Mosquito coast of Nicaragua. There seems to be little doubt on the cyclone’s track and a turn towards the Gulf of Mexico would seem most unlikely. For those that must, the current hurricane severity index rating is 2 out of a possible 50 points (1 size, 1 intensity) which translates into 45 knot gusts and a tiny windfield of just 45 miles with a predicted maximum HSI rating of 8 out of a possible 50 points (3 size, 5 intensity). I would suggest that is nonsense and anyone with a hurricane response plan for the track along the coast of south America, past the Netherlands Antilles and coast of Colombia towards Nicaragua would be well-advised to blow the dust off it now.
Disturbance Seven is now 1200 miles east-sou’east of Trinidad moving rapidly west-nor’west at 20 knots. This has lost shape overnight and the brisk ground speed will inhibit any development over the next few days. The predicted track has curved slightly north and a path across the central to northern islands of the eastern Caribbean, including the Virgin Islands and Puerto Rico is expected overnight on Friday with increasing thunderstorms and gusty winds.
Disturbance Nine has piped up 800 miles south-west of the Cape Verde Islands moving rapidly to the west at 23 knots. Due to the fast forward motion, development is unlikely and this may even catch up and merge with Disturbance Seven over the next few days.
Stand by for stormy, wet conditions across Trinidad, Tobago, and the Windward Islands later today otherwise stand easy.