Subseasonal midlatitude prediction skill following Quasi-Biennial Oscillation and Madden–Julian Oscillation activity

Abstract

Abstract. The Madden–Julian Oscillation (MJO) is known to force extratropical weather days to weeks following an MJO event through excitation of stationary Rossby waves, also referred to as tropical–extratropical teleconnections. Prior research has demonstrated that this tropically forced midlatitude response leads to increased prediction skill on subseasonal to seasonal (S2S) timescales. Furthermore, the Quasi-Biennial Oscillation (QBO) has been shown to possibly alter these teleconnections through modulation of the MJO itself and the atmospheric basic state upon which the Rossby waves propagate. This implies that the MJO–QBO relationship may affect midlatitude circulation prediction skill on S2S timescales. In this study, we quantify midlatitude circulation sensitivity and prediction skill following active MJOs and QBOs across the Northern Hemisphere on S2S timescales through an examination of the 500 hPa geopotential height field. First, a comparison of the spatial distribution of Northern Hemisphere sensitivity to the MJO during different QBO phases is performed for European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis and ECMWF and the National Centers for Environmental Prediction (NCEP) hindcasts. Secondly, differences in prediction skill in ECMWF and NCEP hindcasts are quantified following MJO–QBO activity. In both hindcast systems, we find that regions across the Pacific, North America, and the Atlantic demonstrate an enhanced MJO impact on prediction skill during strong QBO periods with lead times of 1–4 weeks compared to MJO events during neutral QBO periods.

Development of a Statistical Subseasonal Forecast Tool to Predict California Atmospheric Rivers and Precipitation Based on MJO and QBO Activity

“…Anomalously high AR landfall activity was detected for certain MJO/QBO phase configurations at lead times of 3–5 weeks, and these anomalies persisted with decreasing lead time and eastward MJO propagation. Mayer and Barnes (2020), Mundhenk et al. (2018), and Nardi et al.…”

“…Anomalously high AR landfall activity was detected for certain MJO/QBO phase configurations at lead times of 3-5 weeks, and these anomalies persisted with decreasing lead time and eastward MJO propagation. Mayer and Barnes (2020), Mundhenk et al (2018), andNardi et al (2020) demonstrated that the predictability and magnitude of western U.S. AR activity and precipitation anomalies is especially enhanced during certain phase configurations of the MJO and QBO. These studies also revealed that including information about the QBO can significantly modify the empirical relationships between the MJO and AR activity and precipitation.…”

Quasi‐biennial oscillation impacts on Madden–Julianoscillation‐associatedtropical–extratropical interactions and Kelvin waves

“…Feng and Lin (2019) also suggest that enhanced midlatitude westerlies during the westerly QBO might enhance upward propagation of Rossby waves that then influence the NAO. Mayer and Barnes (2020) showed that prediction skill in the midlatitude atmospheric circulation is significantly enhanced associated with MJO events in strong QBO states, with especially enhanced skill during the westerly QBO.…”

Subseasonal Predictability of the North Atlantic Oscillation

“…NAO variability during winter is driven by numerous physical mechanisms including remote tropical forcing by the Madden-Julian Oscillation (MJO) (Ferranti et al 2018, Tseng et al 2018, Mayer and Barnes 2020 and ENSO (Ayarzagüena et al 2018, King et al 2018, Nie et al 2020, sudden stratospheric warmings (SSW) (Sigmond et al 2013, Tripathi et al 2015, Domeisen et al 2020, and eddymean dynamics of the zonal index (Gerber andVallis 2007, Hitchcock andSimpson 2016). These mechanisms may yield similar NAO-like patterns, but each operates over different, overlapping timescale ranges.…”