Sting jets are thought to be responsible for some of the most damaging winds associated with extratropical cyclones in the mid-latitudes. So far they have only been confirmed in the European region, associated with the Shapiro-Keyser model of cyclone development. They have been considered to be much less important in storms forming in the Pacific which can impact the west coast of North America, though new studies indicate that they are theoretically possible, and likely occur in this region. (Do North Pacific sting jet cyclones exist?)
Two sting jets have been postulated as having occurred over the (continental) Midwest USA though. Given that the Shapiro-Keyser model is applied to oceanic cyclones, is it theoretically possible that these continental forming sting jets are genuine sting jet cases?
I don't know if the sting jet identified over the Canadian Maritimes from ex-hurricane Arthur 2014 technically nullifies this question, but I think it remains valid for those storms in the continental centre of North America.