Tropical Storm Dorian to intensify as it moves over the Caribbean

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AccuWeather Broadcast Meteorologist Geoff Cornish with the latest forecast on the track and intensity of Tropical Storm Dorian and Tropical Depression Six off the southeast coast of the U.S.

For the latest on Tropical Storm Dorian, click here.

Tropical Storm Dorian passed over the Lesser Antilles early Tuesday morning, bringing heavy rainfall and gusty winds. Dorian will now set its sights on Puerto Rico and Hispaniola by midweek.

The island group was put on alert for impacts ranging from strong winds and rough surf to localized flooding early this week.

Numerous tropical storm watches and warnings were issued for these islands by the National Weather Service in advance of Dorian's arrival. As of 8 a.m. EDT, the storm was moving over the island of St. Lucia and into the eastern Caribbean Sea with maximum sustained winds of 50 mph.

The Government of Puerto Rico issued an order to freeze prices of basic necessities and orders to regulate profit margins on the sale and distribution of gasoline, liquefied gas, and diesel.

An area of disturbed weather that AccuWeather meteorologists had been monitoring since last week became Tropical Depression Five on Saturday morning. By Saturday afternoon, it strengthened into Tropical Storm Dorian, becoming the fourth named tropical system of the 2019 Atlantic hurricane season.

This satellite image shows Tropical Storm Dorian passing over the Lesser Antilles en route to the Caribbean Sea on Tuesday morning, Aug. 27, 2019. (NOAA/Goes-East)

"Through Tuesday, islands stretching from St. Vincent northward to Guadeloupe should prepare for wind gusts of 50-60 mph, sporadic power outages and localized flooding due to 2-4 inches of rainfall," AccuWeather Senior Meteorologist Dan Pydynowski said.

As Dorian passed over the island of Barbados early Tuesday morning, a 55 mph wind gust was recorded at the Grantley Adams International Airport.

"Following its passage across the Lesser Antilles, including near-direct hits to Barbados and St. Lucia, Dorian will head into the eastern Caribbean Sea," Pydynowski said.

Surf will become dangerous for swimmers and small craft along the south- and east-facing beaches.

The frequency and intensity of rip currents will increase as the seas are stirred.

Dorian has been designated a 1 on the AccuWeather RealImpact™ Scale for Hurricanes.

In comparison to the Saffir-Simpson scale, which has been used by meteorologists for decades and classifies storms by wind speed only, the AccuWeather RealImpact™ Scale for Hurricanes is based on a broad range of important factors. The scale covers not only wind speed, but flooding rain, storm surge and economic damage and loss.

Dorian is a small storm, which will spare large areas from feeling its worst impacts. However, small storms can undergo rapid fluctuations in intensity.

Where will Dorian head next?

After passing through the Lesser Antilles, Dorian will reach the open waters of the eastern Caribbean.

"Dorian is expected to make a bit more of a northward turn and head in the direction of Puerto Rico and Hispaniola around midweek," Pydynowski said.

A factor will be how much interaction Dorian has with Puerto Rico and Hispaniola, as the mountainous terrain in these countries boast a history of tearing tropical systems apart.

"Depending on its exact track and intensity, Dorian could cause flash flooding and mudslides on the steep terrain across Puerto Rico, the Dominican Republic and Haiti during the middle to latter part of the week as 4-8 inches of rain may fall in some areas," he added.

"There is the possibility of tropical storm- to hurricane-force winds in southwestern Puerto Rico and the eastern part of the Dominican Republic, should Dorian pass in between the two large islands, known as the Mona Passage," AccuWeather Hurricane Expert Dan Kottlowski, said, referring to the 80-mile-wide stretch of watch that separates Puerto Rico from the island of HIspanolia.

Such a track with a small storm of Dorian's size might allow it to maintain strength.

However, if Dorian should travel farther west and pass over the middle of Hispaniola, winds would be stronger farther west of the island, but the overall strength of the storm would decrease significantly.

"If Dorian passes directly over the high mountains of Hispaniola and weakens a great deal, it may struggle to regain strength for several days," Kottlowski said.

"However, if the storm manages to dodge the heart of Hispaniola or Puerto Rico and travels northwestward relatively unscathed, it could become a hurricane southeast of Florida this weekend," Kottlowski said.

If Dorian remains a weaker storm, then it will likely take a more westward path through the Caribbean as opposed to making a more northward turn.

"We could be looking at an impact along the U.S. coastline," AccuWeather Chief Broadcast Meteorologist Bernie Rayno said.

"Every place is open for a possibility -- from the east coast of Florida to the Carolina coast. A track toward the Gulf of Mexico is even a possibility, Rayno added.

The exact strength of Dorian by this point will largely be determined by the amount of dry air and wind shear the storm encounters in the Caribbean. While wind shear is currently light over the eastern Caribbean, it won't be an obstacle to Dorian strengthening into a hurricane.

Strong wind shear can lead to the demise of tropical storms or low-end hurricanes. However, a small amount of wind shear can vent a tropical storm or hurricane just enough to allow it to strengthen.

All interests from Puerto Rico to Hispaniola, Cuba and Jamaica should be monitoring the track of Dorian closely over the next few days.

And while it is too early to determine whether Dorian will hold together long enough to potentially impact the Bahamas, Florida and the Southeast states in general, people in these areas should be keeping a watchful eye on the forecast leading up to and through the Labor Day weekend.

Elsewhere in the Atlantic basin, AccuWeather meteorologists continue to monitor Tropical Depression Six off the Atlantic Seaboard.

While this feature is likely to bring minimal impacts to the East coast of the United States, heavy rainfall and gusty winds can sweep across portions of Atlantic Canada late this week.

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