The Gulf Stream, if viewed from above, is a deep dark blue stream of ocean off the Atlantic coast of Florida. It has a clockwise system of currents which transports warm water from the tropics, up the US east coast according to Wiki.
It crosses the Atlantic to northwestern Europe where when it reaches the ice-cold waters near Greenland, the rapidly cooling water sinks and flows south once again back to the tropics.
Studies have shown that the Gulf Stream circulation has begun to slow. Whether this slowing of the current is a result of natural fluctuations or by global heating, going forward, the simple fact is the rapid melting of the Greenland ice sheet from greenhouse gases will slow its flow. Due to an influx of voluminous amount of Glacial meltwater pulsing into the Atlantic, the phenomenon is a serious threat to US cities intensifying the sea-level rise and deadly storm surge from New York to Miami.
In just two years, we have had five Atlantic Category 5 storms that made landfall, Irma, Maria, Matthew, Michael, and Dorian. Climate change will cause hurricanes to become even more apocalyptic due to stalled storms over populated areas and, less wind shear to weaken the storm when they are in the open waters of the Atlantic.
Inside Climate News provides an overview of the aftermath of the second most powerful Atlantic storm on record. The 185 mph windstorm, which had stalled over the northern Bahamas for days, created a humanitarian disaster of epic proportions. Dorian appears to have slowed the speed of the current as a result. The slow down would have piled up water increasing sea-level adjacent to the eastern seaboard.
It also looks like Dorian may also have influenced the Gulf Stream, the strong ocean current that brings warm water from the Gulf of Mexico into the Atlantic Ocean, possibly contributing to localized coastal flooding.
An undersea monitor near Miami indicated that Dorian might have slowed the speed of that current, with powerful winds pushing against it, along with a disruptive underwater churn. A slower Gulf Stream can cause the surface of the ocean to rise by several inches to a foot or more, said Tal Ezer, an oceanographer at Old Dominion University in Norfolk, Va.
That would underlie any storm surge, he said, and the effect can linger for days as it did in 2016 in Norfolk with extended sunny weather flooding the aftermath of Hurricane Matthew, whose path was similar to Dorian's. He said he's looking for that to happen in the coming days.
“After the hurricane disappears, streets remained flooded,” he said. “The drainage system was blocked and couldn't drain the rain.”