Investigating the Effects of Increasing Sea Surface Temperature (SST) in the Northwest Atlantic Ocean on Tornado Activity in the Northeast United States 1990 - 2022

There are global effects caused by a warming climate that will continue to cause severe impacts to the planet. A warming climate has been causing some of the highest increases globally to Sea Surface Temperature (SST) in the Northwest Atlantic (Pershing et al., 2015). These rising ocean temperatures allow for more moisture from the ocean to evaporate into the atmosphere creating instability in the atmosphere and providing the energy that is favorable for storm development. In recent years, the Northeast United States has been impacted by hurricanes, significant rain and flooding events, and tornado activity. The Northeast U.S. is experiencing an upward trend in environments favorable for tornado development because of potential increases to instability parameters such as Convective Available Potential Energy (CAPE) (Brooks et al., 2014). In addition, a Global Climate Model using variables such as varying levels of geopotential heights and 850mb level temperatures suggest that the eastern Mid-Atlantic is again projected to be the region at greatest risk for an increase in the number of tornado days that have tornadoes with an intensity of (F2+) for years 2050 and 2090 (Lee 2011). There is sufficient evidence suggesting that the Northeast region is at risk of increased tornado threats and proves the importance of identifying areas in the Northeast United States that have been experiencing increasing trends in tornado activity, and why it is essential to identify variables that are most influential to annual tornado activity. These extreme weather events put a large population and infrastructure at risk of complete destruction, with severe consequences to the economic stability of the region. This study analyzed tornadic trends between two time periods (1990 to 2004) and (2005 to 2022) using spatio-temporal analysis with GIS for the Northeast U.S. by analyzing the NOAA point tornado dataset through aggregation of touchdown locations both spatially and temporally into 50km hexbins. Guo et al., (2016) suggested for future studies to grid tornado data at different resolutions to further evaluate spatially regionalized tornado variability in the U.S. This is why this study examined data over smaller spatial extents to define localized areas that are experiencing the greatest impacts due to a changing environment. This study also examined annual tornadic activity for the months April to November in the Northeast U.S. for the years (1990 to 2022) and the relationship of tornadic instability parameters, large scale atmospheric patterns, and SSTs in the Northwest Atlantic. A statistical approach was used to determine what predictor variables are most efficient at predicting annual tornado activity and for examining years that outbreaks occurred. Research was also conducted on whether there was an increase in the number of more intense tornadoes between the two time periods and if specific variables impact intensity. Major findings of this study are: statistically significant positive trends in tornado counts in the Northeast U.S. are occurring near coastal areas of the Northwest Atlantic, the SSTs for the Northwest Atlantic and Storm Relative Helicity (SRH) are statistically significant predictor variables and account for 13% explained deviance for annual tornado counts. SRH is the measure of the potential for cyclonic updraft rotation in right-moving supercells, and it was the only statistically significant predictor variable in predicting years with outbreaks/no outbreaks and contributed to the model having an explained deviance of 40%. SRH, NW SST’s and the North Atlantic Oscillation (NAO) were all found to be statistically significant explanatory variables for tornadoes rated as F2 or higher during outbreaks. These findings indicate that SSTs have statistical significance and suggests that warming waters do have certain influences on tornado frequency, intensity, and location of tornado activity within the Northeast United States. If SSTs continue to rise, populations closest to the coast could be most susceptible to future extreme weather events. Potential research with this topic could focus on some of the statistically significant predictor variables that were identified in relation to tornadoes rated (F2+) and topographic features within the Northeast to examine how the terrain influences the locations of the more severe storms.

Author

• Brant, Danielle

• Climate Change
• Northeast U.S.
• NW Atlantic SST
• Tornado

Identifier

hdl:1920/13884

OAI identifier oai:identifier

oai:MARS:1920/13884