Snow began falling on Kiefer OK this afternoon (29 DEC 09) a little before 5 PM, and it is still coming down. This is on top of what remains from the Christmas Eve Blizzard. Both the current system and the blizzard moved SW to NE. Doesn't that sound familiar?
The systems that create the strongest severe springtime thunderstorms usually travel the same direction. What causes this is a trough will set up to the west of the Great Plains, and this makes the jet stream dip to the south around the trough, creating a "valley" or "long wave" in the jet stream pattern. As the jet stream flows from SW to NE, it sets up smaller low pressure centers that move along the jet stream. These "short waves" become the nuclei of severe weather systems.
Reports came out earlier that an El Nino was forming. El Ninos change weather patterns. If an El Nino is responsible for the current pattern, it might persist into and throughout the spring. We could be in for an active severe weather season in 2010.