I think looking at this, it looks like the cold airmass that has been responsible for much of the snow conditions in traditional Tornado Alley areas (my sister lives in this area, and they got snow just yesterday), maybe a real cause for the drop in tornado numbers in the start of this year. El Nino normally doesn't produce strong snow flows at this time of the year, so it is possible that once things warm up, the storms may also fire up - April (Easter) may well be a big month for severe weather there. My sister reckons that the normal March storms that usually frighten the daylights out the locals where she is in northern Texas, have been lacking, as the snow is preventing them. But once the warmer weather finally arrives, the threat will be much greater in her neck of the woods...
Big Pete
BTW the pic below is from snowstorm in northern Texas as of 21/03/2010....
