Interannual Ural Atmospheric Variability Under Slow‐Varying Soil Moisture and Snow Cover: Three Quasi‐Equilibrium States

Abstract In Inner Eurasia, the monthly mean 850‐hPa geopotential height anomaly around the Ural Mountains exhibits a large and irregular interannual variability. Its intrinsic mechanism remains unclear. Based on a nonlinear theoretical model and reanalysis data sets during 1979–2023, we find similar qualitative and quantitative relationships, termed pitchfork‐like (PL) relationships, between the 850‐hPa Ural geopotential height anomaly in June, July, and January, and local soil moisture, snow depth water equivalent, and snow cover in the preceding months, respectively. These months are near the crest and trough of the annual cycle when surface forcing factors vary slowly. These nonlinear PL relationships reveal that the interannual Ural atmospheric variability in June and July (January) is intrinsically a transition between three (two) quasi‐equilibrium states. Moreover, when each forcing factor exceeds its critical threshold, the positive and negative anomaly quasi‐equilibrium states may occur with equal probability, implying a low predictability.