They predicted a stormy hurricane season, but it’s been so quiet so far (knock wood).
You can thank the large outbreak of dust from the Sahara Desert, covering a good part of the tropical Atlantic for most of the month. The dry, dusty air about 8,000 feet up in the atmosphere might make our eyes water, but it hasn’t allowed tropical systems to develop. Over the Caribbean, the upper-level winds have been hostile to any development.
And it’s early. By July, fronts rarely make it to the Gulf of Mexico.
It’s not just the dust, said Bryan Norcross, a hurricane specialist at Fox Weather. There’s the MJO, or Madden-Julian Oscillation. This is described as a broad pulse which slowly travels around the earth and alternatively supports and suppresses tropical activity. The part that supports hurricanes was over the eastern Pacific Ocean during July, when there were three hurricanes.
Meanwhile, the side that suppresses storms was over the Atlantic, keeping things quiet.
“Well, the MJO’s supportive phase is forecast to drift over the Gulf, the Caribbean, and the tropical Atlantic over the next couple of weeks. It’s not certain that this change will be enough to overcome the other hostile factors, including the massive plume of dusty air, but we’ll watch the disturbances coming off Africa to see if there’s a change,” said Norcross.
Remember that the peak of hurricane season doesn’t ramp up until the middle of August, which is also when that protective layer of Saharan dust starts to dissipate. The average date for the first hurricane to form anywhere in the Atlantic, the Caribbean, or the Gulf is Aug. 11, Norcross said.
Historically, a quiet early summer doesn’t predict late August through October.
“Overall, the weather and ocean patterns still look generally conducive for a busy hurricane season, although the tropical Atlantic has cooled off. That tends to make systems develop more slowly as they move off Africa,” said Norcross.