Stratospheric Harbingers of Anomalous Weather Regimes
Mark P. Baldwin,*
Timothy J. Dunkerton
Observations show that large variations in the strength of the
stratospheric circulation, appearing first above ~50 kilometers, descend to the lowermost stratosphere and are followed by anomalous tropospheric weather regimes. During the 60 days after the onset of
these events, average surface pressure maps resemble closely the Arctic
Oscillation pattern. These stratospheric events also precede shifts in
the probability distributions of extreme values of the Arctic and North
Atlantic Oscillations, the location of storm tracks, and the local
likelihood of mid-latitude storms. Our observations suggest that these
stratospheric harbingers may be used as a predictor of tropospheric
weather regimes.
Northwest Research Associates, 14508 Northeast 20th Street,
Bellevue, WA 98007-3713, USA.
*
To whom correspondence should be addressed. E-mail:
mark{at}nwra.com