August Recap – Remarkable Heat, Historic Flash Floods
[(Image from National Park Service)]
[Written by NOAA] A top-10 warm August capped off a distinctly hot summer, as the U.S. saw its third-hottest meteorological summer on record. For the first time since 1997, there was no storm activity reported in the North Atlantic basin during the month of August.
Last month was also marked by several extreme rainfall events across the nation that resulted in historic flooding, according to NOAA’s National Centers for Environmental Information.
The average temperature for August across the contiguous U.S. was 74.6 degrees F, 2.5 degrees above average, and ranked as the eighth-warmest August on record. The contiguous U.S. monthly average minimum temperature was record-warm for the second month in a row during August. California, Idaho, Nevada, Oregon and Washington each ranked warmest on record for August nighttime temperatures.
The average precipitation for August in the contiguous U.S. was 3.04 inches (0.42 of an inch above average), ranking in the wettest third of the climate record. Extreme rainfall events during the month of August contributed substantially to the record-wet August for Mississippi — as well as the third-wettest August for Nevada and Louisiana. However, a few states stayed quite dry last month, with Nebraska seeing its second-driest August on record and Kansas seeing its seventh driest.
Multiple historic flooding events struck: Several extreme 1,000-year flooding events occurred across the U.S. in August. On August 2, parts of southern Illinois were drenched by 8–12 inches of rain in a 12-hour period. An area south of Newton, Illinois, recorded 14 inches of rainfall over the same period. On August 5, Death Valley National Park received 1.70 inches of rain, an all-time 24-hour rainfall record for the area, resulting in substantial flooding and damage to roads and vehicles, temporarily stranding park visitors and staff overnight. On August 22, some parts of Dallas, Texas, saw more than 13 inches of rainfall within 12 hours. Texas Governor Greg Abbott declared a disaster for 23 Texas counties, including Dallas, after storms caused damage and devastating flash flooding.
Drought conditions improved overall: According to the August 30 U.S. Drought Monitor report,offsite link about 45.5% of the contiguous U.S. was in drought, down about 5.9% from the beginning of August. Drought conditions lessened or were eliminated across portions of the Southwest, southern Plains, central Mississippi Valley, Great Lakes, parts of the Northeast and Puerto Rico. Drought conditions expanded or intensified across portions of the Northeast, central and northern Plains, the Northwest and Hawaii.
Edited for WeatherNation by Mace Michaels