But it also has the least significance when correlated with the tornado count in Regions 1 and 2, and tornado days in Region 2. Region 1 shows some correlation with SST1 and SST2 when activity is measured with the number of tornadoes, but no correlation when activity is gauged with the number of tornado days. However, tornado days in this Region are somewhat correlated with SST3. The ocean area that typically has the most significant correlations when either strong and violent tornadoes or strong and violent tornado days are considered is SST3. With few exceptions, tau - values are negative.
Exceptions have z-values too small for statistical significance.
Even the strongest of the correlations are so weak that they have little prognostic value. Variations in USA tornado occurrences during El Nino and La Nina. Preprints, 19th Conference on Severe Local Storms , Minneapolis, MN., Amer. Impacts of ENSO on United States tornado activity . ENSO related severe thunderstorm climatology of Northwest Missouri.