Such forcing events often occur on the northern periphery of vast areas of continental heat domes that move northward during the summer months.
[2] On July 21, 2011, hot weather over the past week culminated into record-breaking temperatures across the province of Ontario, also in Michigan, Ohio, upstate New York and Quebec, shattering long held records.
[7] Daily high temperatures warmer than normal began on the southern plains during May 2011, accompanied by one of the most severe droughts ever recorded.
[8] In Oklahoma, by August 3, several locations in the southwestern portion of the state had recorded 43 consecutive days exceeding 100 °F (38 °C).
In addition, the area set a new all-time hottest minimum temperature of 86 °F (30 °C) on July 26[10] and tied it thrice in August.
[11] On August 24, a 5-hour long severe thunderstorm hit Southern Ontario that evening which also spawned a pair of weak tornadoes, nothing particularly unusual for August, but it set records for lightning frequency, thought to be fueled by abnormally high Lake Ontario water surface temperatures due to the heat wave.
[citation needed] The National Climatic Data Center in Asheville, North Carolina reported that the United States had the hottest summer on record in 2011.
[1] The continuing heat and drought resulted in several lakes dropping to record lows, particularly in Texas and Oklahoma.
Daytime highs in the months of June, July, and August averaged almost 9 °F over prior observed normals.
High temperatures in the months of June, July, and August were 9 °F above normals, and overnight lows were also significantly above norm.
[20] The following data is for the weather station at Will Rogers World Airport, located southwest of the city, which during the summer, experienced a peak temperature of 110 °F (43 °C).
One weather station, located in an urban part of the city, recorded an air temperature of 116 °F (47 °C) on August 3.
[21] The heat wave finally ended on September 15, 2011, when a cold front moved through Central Oklahoma.