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Post-Tropical Cyclone Nestor Will Bring Tornado Threat to Southeast on Saturday
Published: October 19, 2019
A risk of severe weather, including tornadoes, is expected from Central Florida into southern Georgia and the eastern Carolinas on Saturday as Post-Tropical Cyclone Nestor moves into the Southeast.
Southeast surface winds will be pulling warm, moist air across parts of the Southeast ahead of Nestor. This air mass will become increasingly unstable on Saturday.
As a result, the severe weather threat is expected to cover a broad area on Saturday from Central Florida into southern Georgia and along the Carolina coast.
(MORE: Nestor Forecast
Tornadoes are possible in Florida into Saturday evening as Nestor tracks inland.
The severe weather may extend into southern Georgia into Saturday night and early Sunday near the Carolina coast.
Saturday's Severe Thunderstorm Forecast
There will be at least some potential for waterspouts or tornadoes on Sunday along the North Carolina coast and Outer Banks as whatever is left of Nestor races northeastward through the region.
How Hurricanes Spawn Tornadoes
Landfalling tropical cyclones often lead to an increased tornado threat. As a tropical cyclone moves onshore, friction over land causes the surface winds to angle more toward the storm center.
These angled surface winds lead to more vertical wind shear (the change in wind direction and speed at different heights) in a way that favors rotating thunderstorms.
Such tornadoes often develop from “mini-supercells” that form along rainbands. Although these tornadoes are often short-lived, they can be quite damaging. When Hurricane Dorian made landfall in North Carolina last month, an EF2 tornado damaged or destroyed dozens of trailers and manufactured homes in Emerald Isle, North Carolina.
Dorian led to a total of 35 preliminary tornado reports in the Carolinas on September 4-6, according to SPC.
Because hurricanes have stronger surface winds than tropical storms, they often produce especially large tornado swarms. The nation’s most prolific tornado-producing tropical cyclone on record was Hurricane Ivan in 2004, which spawned a total of 120 tornadoes.
Tornadoes accounted for just 3% of all fatalities in U.S. tropical depressions, tropical storms and hurricanes from 1963 to 2012, according to a National Hurricane Center analysis.
The vast majority of deaths resulted from storm surge (49%) and rainfall-related flooding (27%).
Nestor may produce significant surge along Florida's Gulf Coast. However, the storm's rapid motion will reduce the threat of inland flooding from heavy rain.
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