Well what this means is that the vertical upper level winds will increase from west to east across the Atlantic against the easterly trade wind currents that tropical waves travel on to cross the Atlantic from the African coast. This all depends if in deed ENSO does return for the up coming season.
These vertical winds would shear the coldest thunderstorms cloud tops causing warming of the clouds and a disruption of tropical cyclone formation. This would reduce the amount of storms developing in the Atlantic to a below average season.
A good example of the vertical shear affecting cloud structure is, think of a sitting train from the old days with no wind on a clear day. The smoke of that trains smoke stack would go straight up. This is how thunderstorms accumulate around a low pressure area to form a tropical cyclone. Now if that train began to move forward, the smoke would be blown behind the train. That is the same principle of vertical westerly wind shear blowing against towering clouds around a tropical disturbance.
This is why at times when a tropical storm is developing but is moving to fast, like 20 to 25 mph forward speed, it has a hard time keeping its cloud structure intact. The coldest cloud tops which are the strongest storm clouds get blown behind the tropical cyclone causing the cold clouds to warm and weakening the thunderstorms. So this gives you an idea of what occurs.
However, all it takes is one storm to mess up your day. A good example of that was Hurricane Andrew that developed during an EL Niño year. Regardless of this you always need to be ready for any type of disaster, so always have a plan of action, and have a kit ready in case something occurs in your area.