Powerful Hurricane Erin has undergone a period of astonishingly rapid intensification — a phenomenon that has become far more common in recent years as the planet warms. It was a rare Category 5 for a time Saturday before becoming a Category 4,

Over the weekend, northern portions of the Leeward Islands, the Virgin Islands, and Puerto Rico are expected to receive tropical rain ranging from 2 to 4 inches, with isolated totals up to 6 inches. Flash flooding, landslides and mudslides will be the main concerns over the next several days.

Erin has become the first hurricane of the Atlantic season with strong waves and rip currents possible along the East Coast of the United States as early as next week.

Erin has intensified to a Category Four Hurricane as it makes its way toward the East Coast of the United States.

The NHC said it currently expected Erin to become a Category 4 storm later Saturday but to eventually swerve away from the continental United States.

Spaghetti models predict Erin will skirt the U.S. East Coast by hundreds of miles as it moves north through next week.