Why Helene's large size, rapid intensification make it a potent threat

Tropical Storm Helene, soon to become a hurricane, is growing unusually large for a Gulf of Mexico storm, and is now rapidly intensifying. Why it matters: These two characteristics are making it a unique threat to millions of Floridians and people in surrounding states as it moves north-northeastward today and Thursday. Threat level: The storm's large size, with tropical storm winds (sustained at 39mph to 73mph with higher gusts) extending at...