Scientists use cold and warm fronts to forecast the movement of tornadoes, but now they are looking to the seas as well because they have found that warmer Pacific Ocean temperatures are apparently causing tornadoes in America’s heartland.
Newer weather investigations have shown by looking at the Pacific Ocean’s temperature, that it might be a new way to determine the location and type of cyclone activity in the United States, a University of Missouri-Columbia press release states.
Laurel McCoy, who is a science graduate student at the MU School of Natural Resources, and Tony Lupo, who is the chair of atmospheric science in the College of Agriculture, Food and Natural Resources and also a professor at the school investigated parts of data from tornadic events that date as far back as the year 1950. They and a team of graduate students ran several tests to see how the warmer Pacific Ocean temperatures were causing possible tornadoes from all those different years and they found a direct connection.
The team discovered that when the Pacific Ocean surface heat was warmer, there was a 20 percent higher incidence of the development of a tornado that was listed on the Enhanched Fuijta or EF scale. This rating system scale usually ranks tornadoes from EF-2 to EF-5 and is how researchers measure the force of twisters from zero to five by the total amount of destruction they cause.
The researchers also noticed that warmer surface temperatures raised the possibility of tornadoes forming either north or west of what is considered “Tornado alley”. This is a large land area in America’s midwest that is well known for getting a very high amount of tornadoes and cyclone-like weather. McCoy also observed when surface temperatures remained warmer; Illinois, Indiana and Tennessee had a higher number of tornadoes that came in from the southern states.
The differences in sea temperatures impacted the course of the jet stream as it went over the Pacific Ocean and then eventually, onshore to the United States. Storms that can produce tornadoes usually are generated by, and then follow, the jet stream. This helps give explanation to why the researchers discovered the rise in the amount of tornadoes and a variation in where the location of higher temperatures fluctuated, and ultimately why warmer Pacific Ocean temperatures are believed to help cause tornadoes.
Lupo and McCoy investigated the association between tornadoes and a thing known as the Pacific Decadal Oscillation. A PDO is considered a record of various long-term temperature developments that usually last over 25 years. NASA stated that the United States may have recently entered a cooler phase but no one knows for sure if tornadoes will lessen come the next season.
PDO cool periods are categorized by sea surface ocean temperatures which are lower than normal. These are located on the eastern side of the Pacific Ocean and a warmer hook shape of higher than normal sea surface temperatures that spread to the west, north and southern Pacific. During a warm period that lasted from 1977 to 1999, the west side of the Pacific Ocean cooled down and the curved wedge in the east was warm.
During 2011, the United States had over 550 tornado connected deaths. With this new technique of checking the warmer Pacific Ocean temperatures to see if they cause tornadoes, the knowledge just might help save lives in the years ahead.
Written by: Kimberly Ruble