Late June Extreme Heat. How Does Current Heat Compare To Year's Past?

So far, through June 23, we've had 8 total hours with heat index readings at/above 100 degrees in Cleveland. Compare this year to other years shows that the recent extreme heat is well ahead of most years.

Even by the end of June historically rarely shows a big increase in instances with a heat index at/above 100.

Here are the yearly 100 degree heat index hourly totals going back to the early 1930s.  The most ever was the summer of 1936 followed by 1995 and the drought summer of 1998.  More recently, 2012 stands out.

Interestingly, the summer of 1936 featured two instances where the heat index reached and stayed 100+ for 9 straight hours.   July 12 between 11am and 8pm and July 13 between 12pm and 8pm.

Finally the totals for each summer since 2011:

What are the longest periods with heat index readings at/above 100?

1936:  10 hours on July 12 between 11am and 8pm.  Average was 105 (highest:  105)

             9 hours on July 13 between  12pm and 8pm.  Average was 104

1995:   12 hours on July 14 between 12pm and 11pm.  Average was 112 (highest:  115)

             9 hours on July 15 between 9am and 5pm.   Average was 108

            9 hours on August 13 between 12pm and 8pm. Average was 105

1988:   10 hours on July 16 between 11am to 8pm.  Average was 104 (highest:  109)

              9 hours on August 17 between 11am and 7pm. Average was 102

2012:   8 hours on July 7 between 11am and 6pm.  Average was 107 (highest:  113)

Summer Heat Emerging

Interesting temperature anomaly solution by the European AI model for the week of June 19 through the 25th back on June 9th. My idea of a slow start to summer (June 1 starts the clock) is still looking good.

June 9 afternoon solution

Here is the same model late June 10th.  Extreme heat projected in the middle of the US.

GFS wasn't showing any heat on June 9 model output...

GFS did a complete 180.  Now its showing the heat the EURO was showing.

High temperatures Sunday June 23 via Euro AI:

GFS same day:

What's interesting is that the heat is developing over extremely wet ground especially across southern Kansas, Missouri and Kentucky.  Northern Illinois, Iowa and Indiana rainfall is running well below normal since mid May.

How much will these dry conditions feed the heat if this continues into July/August?

Notice the Sonoran High (southwestern US) and the SE ridge beginning to merge by the end of the month. This should be enough to keep temperatures above normal across the Ohio Valley/Central US the final week of June, through the 4th of July and beyond.