I have heard several TV meteorologists classify this as a "Land Hurricane" and indeed, this type of formation is unprecedented. However, the Weather service has chosen to classify this as a derecho. What is a derecho you ask?
According to the NWS a derecho is:
A derecho (pronounced similar to "deh-REY-cho" in English or pronounced phonetically as "") is a widespread and long lived windstorm that is associated with a band of rapidly moving showers or thunderstorms.
Click here to hear how the word "derecho" is pronounced.
Because derecho is a Spanish word (see paragraph below), the plural term is "derechos". In this case there is no letter "e" after the letter "o".
See the website "Facts about Derechos" for further information.
Derechos are typically gust fronts, characterized by "bow echos" on the radar. However, this formation differs from classical derechos in that it it displayed several characteristics indicative of tropical cyclonic type systems.
One of the indicators of so-called "Global Warming" (which is a misnomer by the way -.it should be termed Global Climate Change, but I digress) is that extreme weather events will become the norm. Formations like this may be in our future.