The National Hurricane Center issued a tropical storm warning and a hurricane watch for Puerto Rico on Tuesday morning as Tropical Storm Dorian continues to move across the Caribbean toward the island.
The storm, which weakened a bit overnight as the system hit Barbados, is expected to pass near, or just south of Puerto Rico Wednesday afternoon and evening as a strong tropical storm.
A hurricane watch means that hurricane conditions are possible within 48 hours and a tropical storm warning means tropical storm conditions are expected within 36 hours.
Puerto Ricans have been urged by their governor to prepare for the coming storm. Puerto Rico Gov. Wanda Vázquez Garced declared a state of emergency for the island on Monday.
'I urge citizens to activate their emergency plan with caution and peace of mind,' Vázquez said on Twitter. 'For citizens who do not yet have safe roofs, we will have shelters ready.'
The government's official Twitter account said Monday there were 360 shelters open across the island for a capacity of 48,500 residents. And about 70 hospitals were prepared to handle emergencies, the government said.
After passing by the Puerto Rico, Dorian is forecast to move near or over eastern Hispaniola and move north Thursday, the National Hurricane Center said.
By the end of the week, what's left of Dorian is expected to move toward the Bahamas and possibly into the southeastern parts of the US. Forecasts show Dorian reaching the Florida peninsula sometime this weekend as a tropical storm.
But it's still too early to know what the impact will be, CNN Meteorologist Haley Brink said.
Where it is now
Early Tuesday, the storm was trudging along at 50 mph -- slightly weaker than it was on Monday, after its close pass by the island of Barbados.
'St. Lucia seems to be the bull's eye (Monday night) for tropical storm conditions,' including strong winds and heavy rain, Brink said. The island has discontinued its hurricane watch but remains under a tropical storm warning, the center said.
Dorian will dump up to a heavy 8 inches of rain over the Windward Islands into Tuesday, with some areas possibly drenched by more than 10 inches.
Tropical storm conditions are possible throughout the Lesser Antilles through Tuesday morning and over Puerto Rico Wednesday, the center said.
And the storm will only intensify as it crosses into the Caribbean Sea and possibly turns into a hurricane.
Puerto Rico, Florida prepare
Puerto Ricans, still grappling with the devastation of Hurricane Maria in 2017, are on alert for what could be coming.
'Thankfully I've been preparing since May,' said Krystle Rivera, whose family has been stocking up on water, canned food and gas in anticipation of the hurricane season.
The territory's department of education said public schools will be open only until 1 p.m. on Tuesday as instructed by the governor, to allow for preparations of shelters and staff, the government said.
FEMA Acting Administrator Peter Gaynor said the agency has positioned supplies in Puerto Rico and the US Virgin Islands ahead of the storm -- more than what was in place before hurricanes Irma and Maria in 2017.
'Four Incident Management Assistance Teams are deploying today with another on standby,' he said on Twitter.
In South Florida, a team of more than 200 people from 30 different fire departments were preparing to deploy into the storm's path later Monday, CNN affiliate WPLG reported.
'In this particular situation, we're going to be there before the storm hits, so we'll get a little familiarized with the area that we will be responsible for,' Miami Fire Rescue Assistant Chief Scott Dean said. 'We'll weather the storm where our base of operations will be located, and then as soon as the storm goes through and it's safe, our members will go into the streets and start operations and protect the search-and-rescue efforts.'
This is peak hurricane season
Dorian is the fourth named storm of this hurricane season -- a season that generally peaks in the eight weeks surrounding September 10.
Two-thirds of all the storms produced in a typical season occur during this period.
That's because that is the time when conditions in the tropics become prime for storm development. By the end of August, waters in the tropics have warmed and wind shear across the Atlantic begins to weaken.