Teleconnections Governing the Interannual Variability of Great Plains Low-Level Jets in May

Abstract A spectral analysis of Great Plains 850-hPa meridional winds (V850) from ECMWF’s coupled climate reanalysis 1901–2010 (CERA-20C) reveals that their warm season (April–September) interannual variability peaks in May with 2–6-yr periodicity, suggestive an underlying teleconnection influence on low-level jets (LLJs). Using objective, dynamical jet classification framework based 500-hPa wave activity, we pursue a large-scale hypothesis separately for LLJs are uncoupled (LLJUC) and (LLJC) to the upper-level stream. Differentiating between types enables isolation respective sources variability. In U.S. south-central plains (SCP), LLJCs account nearly 1.6 times more precipitation 1.5 greater V850 compared LLJUCs. Composite analyses 250-hPa geopotential height (Z250) conditioned LLJC LLJUC frequencies highlight distinct planetary-scale Rossby pattern wavenumber 5, indicative circumglobal (CGT). An index CGT is found be significantly correlated both ( r = 0.62) −0.48) frequencies. Additionally, significant correlation frequency NAO 0.33). Further expose decadal-scale variations CGT–LLJC CGT–LLJUC teleconnections linked PDO. Dynamically, these impact LLJ class intensity via anomalies over western United States modulate near-surface temperature gradients across SCP.