The Tampa Bay article
here.

A large cloud of mineral dust from the Sahara Desert is blowing
across the Atlantic Ocean and blocking the development of tropical storms as it
goes.

The dust ball is about the size of the continental United States, and
forecasters said it creates dry, sinking air, along with colder sea surface
temperatures that inhibit the formation tropical weather like hurricanes.

Dust clouds often blow off Africa during hurricane season, but the latest mass
is especially large. It is expected to pass over Puerto Rico on Friday, and
meteorologists said it may eventually even reach southern Florida.