Atlantic Tropical Basin Heating Up

After a relatively quiet start, the tropics are beginning to show some signs of life in the far-eastern Atlantic. An elongated cluster of showers and thunderstorms over the southeastern Atlantic is slowly organizing as it moves generally west to west-northwest. Dry air remains to the north as the system is experiencing little in the way of unfavorable wind shear. Sea surface water temperatures are warm in the system’s path. According to meteorologist Joe Bastardi there are three reasons why development is likely to occur:

1) This system, which may be two combining, is large. Large means that there is plenty of energy to be bundled and so while development make take longer, it could end up stronger. Like Alex, this is developing in a way that if you watch typhoons, you see quite a bit, large systems with more than one center that eventually combine, but that can, if focused, summon a lot of energy;

2) Negatively titled surface trough with it. The surge east of stratocumulus well north of the system, not into and through the system, conserves low level vorticity in the path of the system, while destroys it north of the jet axis. This means high pressure tries to self build north of the storm with lower pressure in the path of it. Negatively tilted systems in the tropics tend to self develop faster since the strong east stream north of the system means the reverse eddy south of the stream is cyclonic, anticyclonic north of the stream, and this helps maintain the system. When the system is embedded in strong easterlies (trades further south) pressures tend to lower southwest of the system, rise on to and north and one gets a fast moving wave that shears itself. A visit to a fast moving stream will help you understand how this works;

3) Outflow signature southwest and south of the system. It already has a channel developed aloft so you are ventilating properly.

A large dome of high pressure will steer the low westward through the week, as it approaches the Leeward and Windward islands by late week.

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