Extratropical Cyclone 3 : A cyclone of any intensity for which the primary energy source is baroclinic, that is, results from the temperature contrast between warm and cold air masses
National Oceanic and Atmospheric Administration's NOAA, National Weather Service, Glossary of NHC Terms, National Centers for Environmental Prediction, National Hurricane Center, Fl, USA 2012. http://www.nhc.noaa.gov/aboutgloss.shtml, (ND/ Hurr Sci - Amer) {146}
NOAA/National Weather Service, National Centers for Environmental Prediction, National Hurricane Center NHC, Glossary of NHC Terms, Miami, Florida, USA 2014. http://www.nhc.noaa.gov/aboutgloss.shtml, (ND/ Hurr Sci - Amer) {916}