NASA’s Terra satellite recently captured this stunning photo of Saharan dust wafting over the Atlantic ocean. It’s one of several outbreaks this summer that some speculate may be contributing to this year’s relatively peaceful storm season.
As noted by Kimberly Miller at the Palm Beach Post, Saharan dust is the strongest it has been in a decade, but it’s not immediately obvious if the dust is among the most important contributing factors to the suppression of tropical storms and hurricanes.
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired this natural-color image of dust sweeping off the coast of Western Sahara and Morocco on August 7, 2015. (NASA image courtesy Jeff Schmaltz, LANCE/EOSDIS MODIS Rapid Response Team at NASA GSFC. Caption credit: Adam Voiland)
Jason Dunion, a research meteorologist for the National Oceanic and Atmospheric Administration’s hurricane division in Miami, told Miller that about “a mile up into the surface atmosphere, what is usually really tropical and juicy, has about half the moisture, which makes it difficult for thunderstorms to form.” And indeed, there may be a relationship between Atlantic tropical cyclone activity and African dust outbreaks.
That said, there are other important factors to consider. For example, El Niño is currently causing dry air conditions, strong wind shear, and below average sea-surface conditions in the Atlantic, which aren’t conducive for tropical storms.
This is what all that dust looks like at 45,000 feet, as seen just northeast of Barbados. (Credit: Jason Dunion, NOAA Hurricane Division)
Officials at the National Hurricane Center are not factoring the Saharan dust for their forecasting, saying it’s just too unpredictable.
“It’s pulses of dust, so it’s now always there, and it can be very discreet,” noted a NHC science official to Miller. “It would be nice if we could continue the rest of the hurricane season being slow, but all we can say is the next five days is expected to be nice and quiet.”