The latest satellite picture shows a well defined eye of about 10 nm in diameter embedded with in a feature called a Central Dense Overcast (CDO), the bright white circular ring around the eye (refer to image below).
The image below is from an ASCAT satellite pass. This satellite can observe wind speed and direction. The wind barbs show a very tightly wrapped cyclonic circulation with very strong winds. The pennants or triangles are for wind speeds of 50 knots, 2 pennants on one wind barb equals 100 knots and the satellite was able to observe winds of this speed.
One of the reasons why Matthew has been able to maintain its intensity is that it is in an area of favorable divergent winds aloft and very low wind shear (image below) as well as being over extremely warm waters, where sea-surface temperatures are in the low to mid 80s.
Hurricane Warnings and Watches along with Tropical Storm Warnings and Watches are posted for Caribbean Islands and the Bahamas:
The official NHC track has Matthew moving in a general north direction. Thus the center of Matthew will not make landfall on Jamaica and could even just pass to the west of Haiti. However, with tropical systems that move in a northerly direction the worst rainfall (and wind is to the right or east of the center. This means that parts of extreme western Haiti could experience hurricane force winds and will also likely receive very heavy rainfall. where amounts of 15-25 inches are forecast (even east to the southwest parts of the Dominican Republic) and some local amounts to 40 inches could also occur here. Needless to say rainfall totals such as these will likely produce catastrophic flooding and flash flooding. The eye of the storm is expected to make landfall on the east end of Cuba late Tuesday resulting in some slight weakening but even so Matthew is expected to remain a major hurricane as it moves across the central Bahamas during late Tuesday through Wednesday.
And by the end of this week Matthew is expected to be a few hundred miles off the Carolina's coastline. It is something that all of the East Coast states will have to watch, including all of us here in Upstate New York. I'll keep you posted.