From NHS Discussion:
The satellite appearance of Matthew has become rather disheveled
looking in infrared satellite imagery since the previous advisory.
Land-based Doppler radar data indicate that Matthew has been going
through an eyewall replacement cycle for the past 12 hours or so,
but the inner eyewall has yet to dissipate within the 35-40 nmi wide
outer eyewall. Both Doppler velocity data and recon SFMR surface
winds and flight-level winds indicate that hurricane-force winds are
and have been occuring within the outer eyewall just 5-10 nmi east
of the Florida coastline. Although the central pressure has
remained steady between 938-940 mb, the intensity has been lowered
to 105 kt based on 700-mb flight-level winds of 118 kt and several
patches of Doppler velocities of 120-122 kt between 5000-7500 feet....
Matthew is expected to slowly weaken some more during the next 12
hours or so while the cyclone completes the eyewall replacement
cycle. By 24 hours and beyond, more significant weakening is
expected due to the combination of strong southwesterly vertical
shear increasing to more than 30 kt and entrainment of very dry
mid-level air with humidity values less than 20 percent. The new
intensity forecast closely follows the consensus model IVCN.