Mass tornado out break

In the contrys mid section we have seen an out break of tornados.

http://www.weather.com/blog/weather/8_15717.html?from=hp_news

http://www.weather.com/newscenter/stormwatch/?from=secondarynav

On May 25th thare were over 160 preliminary tornado's reported.

((Note, this is by me))
Why:One reason is the jet stream is moveing north over the contrys mid section, this is allowing more cold dry air from the north to interact with moist warm air from the south.

Another reason:An increase in mosture from the picific has made what would normaly be only water from the gulf of Mexico, but now even with the GOM (Gulf of Mexico) being calm, the Picific mosture is being drawlin into this.