Tropical weather watchers have had something to monitor for about 24 hours now with the designation of invest area 96L out in the far eastern Atlantic. While it is a sign of the changing pattern and move towards the climatological uptick in hurricane activity, I don’t think this particular system is, by itself, anything to be concerned with – at least not yet.
As I pointed out yesterday, water temperatures in the region of the MDR or Main Development Region are warm enough to support tropical storm formation. We have an area of energy, the tropical wave, entering the Atlantic from Africa and it would seem that all systems are go for this to develop. Let me explain, at least the way I see it, why this probably won’t happen.
Wind shear is low, water temps are warm, so why are we not seeing a marked increase in convection or thunderstorm activity with 96L? I believe it has to do with the overall instability of the atmosphere in the region. The air is still not quite moist enough in the mid levels and perhaps there is still a layer of warmer, more stable air present over the deep tropics. To put it in simple terms: the lack of instability seems to have a cap on thunderstorm development. This seems to have been an issue for development potential for the past several years, dating back most notably to 2013. However, last year, we saw hurricane Fred develop way out in the east Atlantic, almost in the same vicinity of where 96L is now. So what gives? Fred formed at the end of August, we’re only at the end of July. I think the additional time for the atmosphere to moisten up really does matter. Africa tends to contribute an incredible amount of dry, warm, particulate-laden (dust) air in to the MDR and this just takes time to mix out.
So what does this mean for 96L and the rest of the hurricane season? I believe that these recent robust tropical waves will progress westward with little fanfare, only to spring to life farther to the west where conditions are generally more favorable. Then, as the season evolves towards late August and in to September, the chances of one or two long-track hurricanes will go up. After all, the water temperature profile in the deep tropics is warmer than average just about everywhere. There is no abnormal cooling this year and no El Nino effects present. In short, it is only a matter of time and if these systems do in fact lay quiet as they work their way west before developing, then it could mean a very busy landfall season for the countries of the western Atlantic Basin – which of course includes the United States.
For now, 96L will be an interesting topic of conversation. In the longer term, I would be surprised if it developed further – but it won’t just disappear and we may have to deal with it later on when it reaches the western Atlantic. I guess time will tell – it always does.
I’ll have more this afternoon in my video discussion which is posted to our app, Hurricane Impact, and to our YouTube channel.
M. Sudduth 9:45 AM ET July 28