Excessive Heat in Douglas, Nebraska

For 7 days, the high temperature in Omaha was above 93. The highest observed temperature was 104 on August 24. The peak heat index reached at least 105 each day. The highest calculated heat index was a 117 on August 22.

An Excessive Heat Warning was in effect for portions of the forecast area for 7 days as a heat wave dominated the area. This was the longest duration Excessive Heat Warning that the Omaha office has issued. A total of 10 temperature records at Omaha, Lincoln, and Norfolk were tied or broken as the air temperature routinely topped 100 and overnight low temperatures largely remained above 75. High dew points led to heat indices that routinely topped 110.

The heat wave began on August 19 as a mid-level ridge moved over the central CONUS. High temperatures during the stretch of hot weather climbed into the mid to upper 90s with a few locations topping 100. Dew point temperatures were very high climbing into the 70s with some ground stations in southeast Nebraska and southwest Iowa reaching 80. A temperature of 107 was observed at Beatrice as strong afternoon mixing led to a drop in the dewpoint and a spike in temperature. This was the highest observed temperature by an automated station during the heatwave. Roughly 70 miles to the east, Falls City reached a temperature of 99 with a dew point of 84 which resulted in a heat index of 128. That 128 heat index was the highest of the entire country during the heatwave. It may be the highest calculated heat index ever for Nebraska.

A cold front moved into the area on August 20, but only brought relief to northeast Nebraska where temperatures were mostly at or below 90 The heat continued in southeast Nebraska and southwest Iowa where heat indices ranged between 105 and 110 as temperatures were in the mid 90s and dew points in the upper 70s.

The Excessive Heat Warning was expanded to include the entire forecast area on Monday August 21 and was in effect for the entire area through Thursday August 24. The warning was in effect on August 25 for southeast Nebraska (including the cities of Omaha and Lincoln) and southwest Iowa. Temperatures during this period routinely reached 100 and heat indices topped 110. Little relief was had at night as overnight temperatures remained above 75. Lincoln observed 5 straight days of 100 temperatures from Aug 21-25 (and 6 of 7 days including Aug 19). That was the longest such streak for Lincoln since July 21-25, 2012.