From AP:
A supersized El Niño’s decapitating winds and the Gulf of Mexico’s toasty, storm-fueling waters are battling over the future strength of Hurricane Isaias. And the storm’s tilt and eye show who’s winning. It’s called wind shear and it pushes the tops and middle of storms around, making them lopsided and keeping them from making a complete circular eyewall, which is when storms can really power up, Klotzbach and University at Albany’s Kristen Corbosiero said.
The other ingredients for a storm to turbocharge a storm are pushing back. There is plenty of fuel in warm water and moisture. The Gulf of Mexico is about 2.7 degrees (1.5 degrees Celsius) warmer than normal. “But there’s a certain point where it’s like, I don’t care how hot the waters are and how much moisture you have, if shear gets to a certain point, the shear is gonna win,” said Colorado State University hurricane researcher Phil Klotzbach.