Abrupt change in climate regime from summer to fall 1985 and stability in the fall

Summary This paper treats a dramatic transition between the summer and fall of 1985 when temperature and precipitation anomaly patterns and the associated midtropospheric flow over the coterminous United States and adjacent oceans underwent a strong reversal. After this break in regime, the fall patterns locked into a remarkably stable state. It is interesting that this case confirms a more general statistical result from previous completely independent episodes. The hypothesis suggested to explain this strong change and its subsequent persistence draws upon air-sea interactions over the North Pacific and resulting downstream influences.With 11 FiguresPresented at Eleventh Diagnostic Workshop in Urbana, Illinois, U.S.A. on October 14–17, 1986.