Winter Weather Winter Weather  Winter, Are You Out There?  By
Nick Wiltgen  Recipe for Extreme Cold  If you want snow, you
need cold air. And if you want the coldest air possible, you'd
like to get some super-frigid air from the Arctic to come
screaming south into the U.S.  We took a composite of three
major historic Arctic outbreaks -- late December 1983, late
December 1989, and early February 1996 -- to come up with a map
that shows the optimal atmospheric setup for extreme cold across
the United States.  The common thread is that there is always a
strong northward bulge in the jet stream over the West Coast or
the eastern Pacific Ocean.  On the eastern side of this bulge,
the jet stream dives south, helping to drag bitterly cold air
from Alaska and the Yukon south and southeast into the Lower 48.
In these patterns, temperatures in the 20s below zero can drop
into the Central Plains, and readings can flirt with zero even
at the Gulf Coast.  (WATCH: What happens to boiling water at -22
degrees?)  Oftentimes