Surface temperature map for 5 p.m. CST on 26 June 2012, when the June heat wave was at its peak. The white shaded region represents temperatures of 105°+ and the white outlined area inside the white region represents 110°+. UCAR via wunderground.com

By Dr. Jeff Masters
30 June 2012 […] A historic heat wave on a scale and intensity not seen in the U.S. since the great heat waves of the 1930s Dust Bowl era set new all-time heat records for at least ten major cities Friday. According to wunderground’s weather historian Christopher C. Burt, fifteen of the 303 major cities he maintains records for on the wunderground extremes page have set all-time heat records in the past four days. The only year with more all-time heat records is 1936, when 61 cities set all-time heat records. In 2011, which had the 2nd warmest summer in U.S. history, only ten of the 303 cities set all-time heat records during the entire summer. With the the hottest month of the year (July) still to come, 2012 threatens to rival the great Dust Bowl summer of 1936 for extreme heat. All-time records for any date tied or broken on Friday:

  • 109° Nashville, TN (old record 107° 7/28/1952)
  • 109° Columbia, SC (old record 107° on two previous occasions)
  • 109° Cairo, IL (old record 106° on 8/9/1930)
  • 108° Paducah, KY (ties same on 7/17/1942)
  • 106° Chattanooga, TN (ties same on 7/28/1952)
  • 105° Raleigh, NC (ties same on 8/21/2007 and 8/18/1988)
  • 105° Greenville, SC (old record 104° 8/10/2007 although 106° was recorded by the Signal Service in July 1887)
  • 104° Charlotte, NC (ties same on 8/9 and 10/2007 and 9/6/1954)
  • 102° Bristol, TN (ties same on 7/28/1952-this site now known as “Tri-State Airport”)
  • 109° Athens, GA. This is just 1° shy of the Georgia state record for June of 110° set at Warrenton in 1959.

All-time state June heat records set Friday:

  • 113° Smyrna, TN (old record 110° in Etowah in June 1936)
  • 109° Cairo, IL (old record 108° in Palestine in June 1954)

Also of note: Atlanta, GA hit 104° (its all-time June record), and just 1° shy of its all-time record of 105° set on 7/17/1980. The forecast for Atlanta on Saturday calls for a high of 105°F, which would tie for the hottest day in the city’s history. Wunderground’s weather historian Christopher C. Burt has a new post called The Amazing June Heat Wave of 2012 Part 1: The West and Plains June 23 – 27 summarizing the early portion of this week’s historic heat wave. He plans to make a follow-up post on Sunday summarizing the records set on Friday and Saturday.

Extreme storms and extreme heat hit the U.S.