Lee has undergone a remarkable round of rapid intensification since becoming a named storm. In just 24 hours, Lee went from a tropical storm to a powerful category 5 hurricane with maximum sustained winds of 165 mph. 

This crushes Hurricane Franklin, which had peak winds of 150 mph, for strongest storm of the 2023 hurricane season. There has been signs of weakening in Lee over the past few hours, hence why the eye has decreased in size.

It seems the storm is encountering a bit of wind shear (change in wind direction with height) from the southwest. When it comes to tropical cyclones, the stronger the wind shear, the less chance the storm has for intensification. Another reason why tropical cyclones could weaken would be if it underwent an eyewall replacement cycle (ERC).

These are very common with strong tropical cyclones. As these storms strengthen, the eyewalls become tighter and more intense until they reach maximum strength. It’s at this point when a new eyewall may begin to form on the outside of the previous inner eyewall, cutting off the fuel for the inner wall and eventually leading to its demise. This will weaken the storm a bit. But once the cycle is complete, the strengthening process starts up again. 

The latest cone of uncertainty from the National Hurricane Center takes Lee’s center northwestward, placing it north of Puerto Rico by early Tuesday. From there, Lee is expected to make a sharp turn to the north. But the timing of that turn is still a huge question mark, which is why those on the east coast will need to monitor this storm.