When Did Irene Stop Being a Hurricane?

On Sunday morning Anderson Cooper of CNN was asking about the strong winds that were being forecast and this brings up something that has really bothered me about the storm: there is really no reliable evidence of hurricane-force winds at any time the storm was approaching North Carolina or moving up the East Coast.
http://cliffmass.blogspot.com/2011/08/when-did-irene-stop-being-hurricane.html