Updated Monday, May 20,2012 @ 15:48
Heat records for the month of May were crushed in the Northern Plains and upper Midwest last week while Tornadoes as big as a mile wide and fist-sized hail battered states from Texas to the upper Midwest. (Temperature map right) Last week, triple-digit readings smashed long-standing May 14 daily records, with a margin as much as 7° at Norfolk, Nebraska.
At Sioux City, Iowa, the 106° high also broke the all-time May maximum temperature record.
Sioux City climate records date back to 1889. At both Omaha and Lincoln, Nebraska, it was the earliest 100° temperature on record, surpassing the previous records of 5/29/1934 and 5/24/1967, respectively.
The temperature extremes were a reflection of a strongly anomalous circulation pattern along a very strong ridge of high pressure that extend from the eastern Pacific to the Great Lakes near the middle of the atmosphere, while a deep low pressure area was located off the Mid Atlantic coast.
Last week, thunderstorms tore through northeastern Texas as the result of the anomalous circulation pattern. Warm and humid winds blowing from the Gulf of Mexico collided with hot and dry winds from West Texas, resulting in a twisting motion of the lower atmosphere. The National Weather Service in Ft. Worth, Texas issued a report saying 16 tornadoes hit Texas on Wednesday. The tornado that struck Granbury was given the rating of EF-4, with winds estimated between 166 to 200 mph.
A massive storm front swept north through the central United States on Sunday. Nineteen tornadoes touched down hitting parts of Iowa, Oklahoma, Kansas and Illinois, according to the National Oceanic and Atmospheric Administration (NOAA) and local news reports. Hail stones, some as large as baseballs, were reported from Georgia to Minnesota, the NOAA said.
Again Monday afternoon, a mile-wide tornado described by the National Weather Service as “large and deadly” touched down south of Oklahoma City, in the suburb of Moore, causing widespread destruction and fatalities. Two elementary schools were completely destroyed. Those schools are Briarwood Elementary in Oklahoma City and Plaza Towers Elementary in Moore, Okla.
Scientists have long warned us that climate change would bring more extreme weather patterns, with more frequent and intense weather events. The huge tornado that tore through the Oklahoma City suburb of Moore on Monday had winds of up to 200 miles per hour, or more. Early data suggests this tornado may be the strongest tornado ever recorded - ever. Is CO2-based atmospheric warming a factor in the latest Oklahoma City tornado? Scientists can't say yes or no, with certainty.
Global warming is making the earth a more dynamic and violent place. The fossil fuels that human civilization burns worldwide dumps more than 35 billion tons of the CO2 green house gas into the atmosphere every year.
As the amount of that green house gas builds in the atmosphere year after year, it traps more and more of the sun’s energy in our narrow envelope of atmosphere. That increasing energy potential is increasingly expressing itself in many ways. We don’t know for sure that any particular tornado comes from climate change; There have always been tornadoes. But we do know that we’re seeing epic levels of thunderstorm activity, of flooding, of drought, of more wide spread EF-4 to EF-5 super tornadoes, of the things that climatologists have been warning us about.
Yet, Republicans continue to avidly reject the scientific evidence for climate change.
The type, frequency and intensity of extreme weather events are predicted to change as Earth’s climate changes. Changes in some types of extreme events have already been observed, for example, increases in the frequency and intensity of heat waves, droughts and perhaps even tornado swarm events. Texas, Oklahoma and Kansas are call tornado alley for good reason. But day after day of swarms of a dozen, two dozen or more tornadoes, some as much as a mile wide super tornadoes, seem anomalous, even for tornado alley.
In closing, we may never know whether larger global warming factors were at play in Monday's Oklahoma City storms. All we can do at this moment is react to them and give the people of Oklahoma all the help they need.
