Associations of Jet Streams with Tornado Outbreaks in the North America

Abstract

Jet streams, a current of fast winds located about seven miles up near the tropopause, are major weather driving factors in the mid-latitudes. Using the Modern-Era Retrospective Analysis for Research and Applications (MERRA) reanalysis data resources for the period 1979 to 1988, we defined the latitudinal distribution of daily wind maxima by month, and analyzed latitudinal distribution of the highest daily wind speed at the selected longitude in the 19 th week of the year. We showed the typical diving pattern of jet stream over Central America in spring. We found that latitudinal distribution of daily wind maxima was concurrently oscillated with latitudinal distribution of tornado outbreaks in April, May and June. KZ filter smoothed latitudinal distribution of highest daily wind speed on tornado days showed a substantial increase in number of daily wind maxima over tornado alley region, compared to that on non-tornado-days.