Note DetailSome Climate Cycles
3/15/2008 5:12:00 PM

Steve asks: “Elwynn could you review where we stand
in the weather cycles that will impact weather
trends in the next few years?”

   We (from Iowa to Virginia) are just past the
peak of the 30-year wet cycle and must expect the
next 20 or so years to have more dry years than we
have been having in the past 15 or 20 years.
   We should heat the peak of the 89-year warm
period about 2025.  Then if nature still controls
the weather we will note a cooling after that.
   We have just entered what appears to be
the harsh 20-year period for winters related to
the North Atlantic Oscillation  (NAO) having
enjoyed rather mild winters since the mid-80s up to
about last winter.
   The Intermountain West appears to be at the end
of the decadal drought phase of the North Pacific
cycle.  They had rather dry conditions 6 years out
of the past 9 years.
   The saw tooth pattern of Arctic Outbreaks
appears to have peaked this winter opening the way
for a few years of few (as opposed to 7 so far this
winter) such cold air intrusions.  This assumes
that this (and not next year) is/was the peak of
the cycle.  This cycle seems to be expressed from
Utah to Wisconsin. 
    Remember that it is changes in the shorter
cycle events (7 to 42 days) that have the most
immediate impact on our season.  And I have not
talked about the possible 60-year hurricane cycle
that may be in the more active phase beginning back
in 2004.                  --  Elwynn  --

Iowa State University Extension