Tropical Cyclones named Diamondra and Eunice swirl over the central Indian Ocean in this composite satellite image. Neither storm was particularly strong, nor were they expected to make landfall or cause significant damage. But their close proximity offered striking views to satellites. The Visible Infrared Imaging Radiometer Suite (VIIRS) on Suomi NPP captured the lower image, another composite.
The two storms were about 1,500 kilometers (930 miles) apart when VIIRS imaged them. Eunice, the stronger of the two, was located to the west of Diamondra. Eunice had maximum sustained winds of about 160 kilometers (100 miles) per hour, while Diamondra’s maximum winds topped out at about 100 kilometers (60 miles). Both storms were moving in a southeasterly direction.
If two tropical cyclones draw near each other, they begin to rotate cyclonically around an axis connecting their centers—something meteorologists call the Fujiwhara Effect. Such binary storms can even merge if their centers get close enough.