eye potentially catastrophic category hurricane irma move away barbuda head towards st. martin u.s. national hurricane center say advisory hurricane irma 145 miles 235 km east st. croix maximum sustain wind 185 mph 295 km/h nhc say core irma likely move portion northern leeward islands move near portion northern virgin islands wednesday say story correct headline fix source u.s. nhc nrc hurricane irma move away barbuda nhc