As Hurricane Irma continues to move west as a Category three storm, in what still is said to be an indeterminate path, according to the latest projections from Met Scientist Michael Ventrice, it now looks like Florida has the highest probability of a US landfall…
…though that doesn’t mean the Gulf of Mexico can rest easy. Hurricane forecasting is notoriously inaccurate one or two weeks out...
Before it nears the US, however, the storm is headed toward the Northern Caribbean, threatening to bring flooding rain and damaging winds to the Leeward Islands. Preparations for the storm should already be taking place in these areas, according to Accuweather.com.
“Rain and gusty winds may start as early as Tuesday,” AccuWeather Senior Meteorologist Rob Miller said.
According to Accuweather, Irma’s intensity has vacillated over the past few days. But the storm is expected to strengthen to a category four hurricane with sustained winds of 130-156 mph as it approaches the islands. Thereafter, the storm will turn to the north and west over the coming days. This track will put Antigua and Barbuda, Montserrat, St. Kitts and Nevis, Anguilla and the British Virgin Islands, in the brunt of the storm's rain and wind spanning Tuesday and Wednesday.
Cruise and shipping vessels in the hurricane’s path will need to reroute.
Later in the week, Irma will move close to Puerto Rico and Hispaniola with the worst of the storm expected to miss the islands to the north. Even so, rough surf, gusty winds and heavy rain will increase.
Experts are concerned that the Turks and Caicos Islands and the Bahamas could face dangerous conditions at the end of the week and into the weekend as Irma passes nearby or possibly through the islands. Impacts will be severe if Irma maintains its strength and passes over them.
Ultimately, the storm could land in Florida, Georgia, the Carolinas or even closer to the Delmarva Peninsula. Or it could curve northward and miss the east coast entirely.
“The eastward or northeast progression of a non-tropical system pushing across the central and eastern U.S. this week will highly impact the long-range movement of Irma,” AccuWeather Hurricane Expert Dan Kottlowski said.
How fast or slow this non-tropical system moves will determine whether Irma takes a west-northwest path toward the southern Atlantic Seaboard or gets steered north and away from land.
* * *
Readers may be wondering, if the storm slams southeast Florida, as is looking increasingly likely. Well, the Miami Herald spoke with one engineer who built a “dynamic” weather forecasting model that incorporates data like rainwater evaporation rates and how much of a given surface area is paved.
“Omar Abdul-Aziz, an engineer and assistant professor at West Virginia University, has done just that with a new model he built while at Florida International University as part of a state-funded project to improve hurricane loss models. At the request of the Herald, he agreed to run three rainfall scenarios that might resemble Hurricane Harvey.
The maps he produced stretch from Homestead north to Port St. Lucie, not including barrier islands which are separate land masses, and depict flooding after 48 hours from 20 inches of rain, 30 inches of rain, and 40 inches of rain.
Because the maps cover a large area, they don’t show flooding at street level. But Abdul-Aziz said they do provide a far more accurate picture of what would happen across the region.”
If his models are accurate, residents of densely populated cities like Miami might want to start bracing for floods. Abdul-Aziz found that floodwaters in parts of Miami, Hialeah, South Dade and Fort Lauderdale could rise between nine and 17 inches at least with this amount of rain. And with 40 inches of rain, flooding in those same neighborhoods, as well as many more, rises to between 23 inches and more than three feet — enough to begin damaging houses and partially submerge cars.
“Because of the flat land and low elevation, water does not move fast. It goes slow and the drainage capacity is not designed to take that much rainfall,” he said.
To build the model, funded with $533,000 from the state, Abdul-Aziz used the Environmental Protection Agency’s latest stormwater management model, which has been used since the 1970s to help communities plan water and sewer systems. They include local hydrology, land cover, ground level and local climate, but cover a smaller area.
Abdul-Aziz mapped out three different flooding scenarios below:
To be sure, the storm is still at least a week away. Depending on atmospheric conditions, it could menace a wide stretch of the US east coast. If it’s still a powerful category 3 or 4 storm when it hits – as projections suggest it would be – the US could be bracing for its second major natural disaster in two weeks.