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San Diego, U.S.A. — EarthRisk Technologies, a San Diego-based weather analytics company, confirmed on August 20 that the Midwest and Eastern regions of the United States experienced the most extreme and persistent heat on record since 1948 in June and July of this year.
HeatRisk, the company’s web-based platform that utilizes historical data to analyze the risk for extreme warm weather events up to 40 days in advance, verified several key patterns conspired to drive the record-breaking temperatures.
“The cumulative HeatRisk index for the Midwest/East United States was higher than any other June-July period on record since 1948,” according to David Margolin, EarthRisk’s Director of Meteorology. “That’s nearly 10 percent warmer than the next highest HeatRisk value which was recorded in 1988.”
The geographic region in EarthRisk’s study stretches from Chicago to Boston then southward to Charlotte, North Carolina and westward to Little Rock, Arkansas. Residents may remember last summer’s blistering heat in early July, but 2011 pales in comparison to 2012.
“According to our HeatRisk index, 2012 was 36 percent more extreme than 2011,” added Margolin.
EarthRisk also quantifies a measure of extreme cold, called ColdRisk.
“As you might expect, the ColdRisk value for June/July was very low,” said Margolin. EarthRisk estimates that ColdRisk in 2012 was the fourth lowest on record since 1948. Only 1949, 2010 and 2011 featured a smaller measure of extreme cold temperatures during the first part of the summer.
EarthRisk also analyzes the overall atmospheric patterns that correspond to extreme heat and extreme cold throughout the year. EarthRisk cites a strongly northward shifted jet stream across the eastern Pacific and North America as one of the primary factors leading to heat, especially in June.
“We call this a ‘pattern dipole’ focused over the eastern Pacific and it was one of the strongest such jet stream patterns observed since 1948,” said Stephen Bennett, EarthRisk’s Chief Science and Products Officer. “This particular pattern was so strong, nearly three-and-a-half standard deviations, on June 16, 2012 – which is very rare.”
Strong low pressure in Alaska in late June and early July was also a culprit. “It’s also very rare to see this particular pattern so strong,” added Bennett. “On June 17, we observed a value stronger than 2.5 standard deviations.”
These synoptic scale atmospheric conditions are related to a broader pattern that has been stubbornly persistent throughout June and July known as the “Global Wind Oscillation” or GWO. EarthRisk scientists Dr. Klaus Weickmann and Ed Berry have been researching the GWO for the past decade and their research indicates that when the GWO is persistently low, as has been observed most of the summer so far, the weather pattern across the U.S. tends to be repetitive.
“These patterns tend to feature repetitive heat from the Rockies eastward across Canada and the Northern Tier of the U.S.,” Bennett said.
EarthRisk’s scientists believe a combination of these various patterns have conspired to drive the most extreme early summer period since 1948 across the most populous region of the United States.
About EarthRisk Technologies:
EarthRisk Technologies is a San Diego-based software company founded in 2010. The company’s product suite, TempRisk, is a web-based platform that crunches 60 years of weather data to formulate the odds of cold snaps and heat waves 40 days in advance, a lead-time that is twice as long as any in the industry.
Trading groups, power producers and energy traders on four continents use TempRisk for a climatological edge in their investments. For more information, visit www.earthrisktech.com