Storm Hermine

Hurricane Hermine was a tropical cyclone when it made landfall on the Florida Gulf Coast, but it has since undergone a transition to a non-tropical cyclone. So, what does that actually mean and does that really change anything as far as weather impacts are concerned?

On Saturday, the National Hurricane Center designated Tropical Storm Hermine "post-tropical," meaning that it has technically lost many of its tropical characteristics and is more closely related to a mid-latitude (non-tropical) storm. Hermine was moving off of the North Carolina coast at that time. As indicated earlier, this is NOT a downgrade!

The reason for Hermine's transition is that it interacted with mid-latitude features such as an upper-level trough (dip in the jet stream) and a frontal boundary at the surface. These features are creating the storm's physical changes and are also allowing it to become stronger.

In addition, water temperatures off the mid-Atlantic Coast (80 degrees and above in some locations) are well above seasonal averages and that environment is more like you would usually find farther south. This will also help to maintain the strength of the storm and there is a slight chance that Hermine could regain tropical characteristics later.

Although it's physical structure is changing,  Hermine remains an extremely dangerous storm for the East Coast. Impacts that are associated with tropical cyclones such as dangerous storm surge, flooding rain and strong winds will continue. Since this storm is expected to stall for a few days, these impacts will continue for a prolonged period.

https://weather.com/storms/hurricane/news/hurricane-hermine-transition-impacts-forecast-post-tropical