After fast start to the tropical season, Atlantic is closed for business
Where are the hurricanes?
JACKSONVILLE, Fla. – Talk about being left in the dust!
After setting records for the earliest 'C' and 'D' storms in the Atlantic, the tropical season seems to have grinded to a screeching halt. In fact, there is no hint of any development through the remainder of July.
The reason? Dust and lots of it! It's what is known as the Saharan Dust Layer (SAL). This dust originates over the Saharan Desert and is blown offshore into the main development region of the Atlantic which chokes the life out of development chances of easterly waves.
Take a look for yourself at the image above provided by the University of Wisconsin. The red area is thick dust in the air and the yellow areas are lesser concentrations of dust.
Now when you think of dust, what comes to mind? For me, I think dry, static, dirt, sandy and in desperate need of something to drink. Essentially, it's the same over the Atlantic; very dry.
The dust acts as a stabilizing agent. When the atmosphere is stable and dry air dominates, little to no convection or thunderstorms can develop. As the dust pushes west off the continent of Africa, it also brings with it high wind shear which can also decapitate any storms that manage to develop.
Some dust can act as a coalescent agent to get rain drops to form. Too much dust can suck the moisture right out of the atmosphere.
The Weather Authority's Richard Nunn said, "We've all seen the little packets that come with new electonic devices that say "Do Not Eat." Inside of that dessicant packet are little crystals or pellets that absorb moisture. It's kind of like the Damp Rid or moth balls that your grandparents used in closets. Sand from the SAL is like natures dessicant. Too much sand in the air results in a dry atmosphere and conditions that are not conducive to tropical formation."
Since dry air is dominated by nitrogen rather than water vapor, it heats much more effeciently. This warmer, dry air creates an inversion between 5,000 and 15,000 feet. This acts as a cap to put the kabosh on development. Think of it has putting the lid on a pot of boiling potatoes. The steam coming off the pot can't rise and neither can the moisture in the Atlantic to form clouds and storms.
Finally, the pressures over the tropical Atlantic's main development region are high. When high pressure dominates, that means the air pushing against the surface is heavy and can't rise. As long as pressures remain high and the dust stays thick, you can stick a fork in any development chances over the next few weeks.
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