Irma maintained Category 5 intensity with 175 mph winds as its eye crossed the small privately-owned Big Ambergris Cay, but the core of hurricane missed the capital of Cockburn Town, and may pass just south of Providenciales, the most heavily populated island in the country.

Hurricane hunter observations on Thursday evening showed lower winds in Irma than earlier in the day, and found a distinct double wind maximum, caused by concentric eyewalls. By my count, this may be Irma's 7th eyewall replacement cycle, and appears to be the first one that has notably degraded the hurricane's maximum winds. The Air Force hurricane hunter plane in the storm Thursday night found top surface winds near 165 mph on their first pass through the eye near 7:35 pm EDT, but only 140 mph on their second pass through near 9 pm EDT. The pressure stayed nearly constant in the two passes, at 920 and 921 mb, respectively. The reduction in the peak winds is not necessarily a good thing, since the hurricane hunter data showed that the hurricane-force winds of the storm had spread out over a larger area, which will increase the storm surge. In addtion, the fact that Irma maintained its very low pressure may mean the aircraft may have missed sampling the strongest winds of the hurricane.