High temperatures on Wednesday, December 25 2019 broke records across the state of Iowa and much of the Midwest.
Des Moines reached 60 degrees, breaking the 1936 record of 58 degrees. Cedar Rapids reached 58 degrees, breaking the previous record of 54, according to Weather Underground.
The Christmas day highs were preceded and followed by unseasonably warm weather as well.
Though a 60 degree December day is not unheard of (the Des Moines Registerreports that at least one December day in Iowa has reach 60 degrees 29% of years since 1878), average winter temperatures in the Midwest are undoubtedly rising.
A Union of Concerned Scientists report shares that average annual winter temperatures in the Midwest have risen about 4 degrees since 1980. Winter temperatures are forecast to continue rising, while snow and days below freezing will decrease.
This past September was the 15th wettest September on record for Iowa, according to the Iowa Department of Natural Resources. This has been able to remove drought locations that happened over the dry summer months.
Iowa’s average rainfall amounted to 6.17 inches — 2.79 inches above normal for September. The temperature average to 68.2 degrees, making it the ninth warmest September on record. While it has been able to offset drought damage, the DNR stated in a press release that saturated soils make the state vulnerable to flooding if rainfall continues.
The National Oceanic and Atmospheric Administration found that June 2018 to May 2019 were the wettest 12 months on record for Iowa since 1895. Iowa received extreme flooding in the spring from the Missouri River. Early snow melt from not only Iowa, but also South Dakota and Minnesota, contributed to the rising water levels in the river.
Iowa also received heavy rainfall, which some reports attributed to a changing climate and warm ocean temperatures. In the June to May time frame, Iowa received 50.73 inches of rain.
Effects of the changing climate in Iowa were seen into the summer months. The Iowa Climate Statement was released Sept. 18, which outlined trends in temperatures and how Iowa can expect more 90 degree days in a year. The report also serves as a warning to Iowans and Midwesterners to expect extreme heat, and provides guidelines on how one can properly prepare.
Early Wednesday morning, while many across Iowa were still asleep, records were broken by the so-called “Polar Vortex” over the Midwest. Before 4 a.m. Des Moines saw a minus 20 degree temperature, making it the coldest Jan. 30 the city has seen in recent history. Waterloo got an even colder minus 24 degrees, breaking the same record in that city. Farther north, temperatures reached minus 29 degrees, as reported by the Des Moines Register.
Windchill made the cold temperatures feel even more brutal. In Cedar Rapids, windchill Wednesday morning reached minus 55 degrees, a tie with the 1985 record for the coldest windchill ever recorded there. According to the Register, winds were steadily between 15 and 25 mph, but at times blew into the mid-30s.
Climate change and extreme cold
Some studies suggest that such extreme “Polar Vortex” events in the Midwest could become more common with climate change, though more research needs to be done to make a definitive call on the matter.
It appears that warmer arctic temperatures cause the jet stream, a westerly moving band of air circling the northern part of the globe, to dip farther south, bringing the North Pole’s extreme cold into the United States. Read this article from National Geographicfor a more in-depth look at the science.
The data from 2017 also reveals that last year, atmospheric greenhouse gas levels were the highest ever recorded. The average global carbon dioxide concentrations reached 405 parts per million. This far surpasses any carbon dioxide concentrations from previous climate data, as well as C02 concentrations found in ice cores from well over half a million years ago.
The report also contains information about continued sea level rise, ocean surface temperatures, coral bleaching, and declining polar ice cap coverage. To read the State of the Climate in 2017, or any of the past reports, click here.
May 2018 is the warmest month of May ever recorded in the United States according to the National Oceanic and Atmospheric Administration. It broke the long held record, which was set back in 1934, during the Dust Bowl. The average temperature recorded in May 2018 was 65.4 degrees, compared to the 64.7 degree average from May 1934.