Fiona washed houses into the sea, tore the roofs off others and knocked out power to the vast majority of two Canadian provinces as it made landfall as a big, powerful post-tropical cyclone Saturday.

Fiona continued to steadily strengthen overnight, with its winds approaching hurricane strength (75 mph or stronger) this morning as its formative eyewall begins to scrape the southern reaches of Puerto Rico.

The center of Tropical Storm Fiona passed over Guadeloupe – part of the chain of islands flanking the northeastern Caribbean – last night, bringing heavy rains and gusty winds, at times reaching nearly 60 mph, while hurricane watches went up this morning for Puerto Rico and portions of the Dominican Republic as the storm tracked westward into the eastern Caribbean.

Tropical Storm Fiona is heading for Puerto Rico and forecasters are warning it likely will grow into a hurricane before hitting on Sunday with extremely heavy rains.

Tropical Storm Fiona, largely held in check from yesterday, is approaching the easternmost islands of the Caribbean today and is forecast to bring squally weather and potentially flooding rains to parts of the northern Antilles this weekend.

Tropical Storm Fiona was forecast to move across the Caribbean’s easternmost islands Friday night before slowing to a spot just south of the Virgin Islands and Puerto Rico late Saturday and Sunday, the U.S. National Hurricane Center said.

The strong tropical wave moving through the central Atlantic – formerly Invest 96L – continued to organize Wednesday, becoming Tropical Depression Seven by late morning and strengthening to Tropical Storm Fiona by the evening.