On April 1, 2013, the IBW experiment expanded to include all National Weather Service WFOs within the Central Region; the IBW experiment was expanded again to include eight additional offices within the Eastern, Southern and Western Regions in the spring of 2014. Within the span of eleven days, the National Weather Service WFO in Norman issued tornado emergencies for parts of the Oklahoma City metropolitan area and central Oklahoma: first on May 20, 2013 for the EF5 tornado that struck Moore and portions of southern Oklahoma City, and again on May 31, for portions of eastern Canadian County and western sections of the immediate Oklahoma City area for another tornado.