Portugal's weather service issued red warnings - its highest level- for high winds or unsafe coastal conditions for 13 of its 18 mainland districts, including Lisbon, the capital.
Leslie, which was a category one hurricane but weakened to a post-tropical storm as it made landfall late Saturday, left 28 people with minor injuries, civil defence commander Luis Belo Costa told reporters.
It will arrive at the central coast Saturday night and continue into Spain as a weaker storm.
"As Tropical Storm Michael turns to the Commonwealth, I want to urge all Virginians to prepare for the serious possibility of flash floods, tropical storm force winds, tornadoes, and power outages", said Governor Northam.
Winds of up to 100kmh uprooted trees in the centre of the country early yesterday morning.More news: Malicious Message Bug Is Crashing PlayStation 4, How To Protect Your Console
More news: Mega Millions Jackpot Soars To $654M With No Big Winner
More news: Indonesia says death toll in Sulawesi quake rises past 2000
Extremadura has also asked its citizens to be very careful if they travel on the roads, warning of possible landslides, flooding of roads and also warned people not to park in dry riverbeds.
Michael, the third most powerful hurricane ever to hit the US mainland, smashed into Florida's northwest coast near the small town of Mexico Beach on Wednesday as a Category 4 hurricane with 155-mile-per-hour (250-kilometer-per-hour) winds.
Over the past 176 years, only Hurricane Vince has made landfall on the Iberian peninsula, hitting southern Spain in 2005, according to weather records.
In October 2017, strong winds from Hurricane Ophelia, which travelled north off the coast of Portugal and western Spain, fed forest fires that killed around 40 people during a heatwave.
The Portuguese government discontinued a tropical storm warning for Madeira, with Leslie expected to reach the southwestern part of the Iberian Peninsula before moving inland into Sunday.