The Seasonality and Regionality of MJO Impacts on North American Temperature

Abstract

It is widely accepted that the Madden‐Julian Oscillation's (MJO) influence on North American temperature is strongest in winter. A growing body of literature demonstrates that the MJO also influences North American weather in other seasons. Here we use observations to investigate the seasonality and regionality of the MJO's impact on weather station daily maximum air temperature over North America (NA). Consistent with previous work, we find the strongest MJO signal in temperatures over eastern NA and Alaska during winter. However, the peak MJO signals over much of central NA, western NA, and south Texas occur outside of winter. We investigate how this translates to forecast skill and conduct leave‐one‐out cross‐validated empirical forecasts of maximum surface air temperature using the phase of the MJO and lead time as predictors. Our results suggest the potential for more skillful long‐range forecasts of weather over NA during spring, summer, and fall.

Projected Changes in the Seasonal Cycle of Madden‐Julian Oscillation Precipitation and Wind Amplitude

“…The results presented in this paper agreed well with earlier papers about the variations in MJO seasonality observed in the recent decades (Lu & Hsu, 2017;Zhang & Dong, 2004) with an extension to a future warmer climate. Since the MJO is the dominant mode of intraseasonal variability in the global atmosphere that contributes to extratropical teleconnections in summer, our results imply a potential delay in seasonality impacts of the MJO on North American temperature (Baggett et al, 2018;Jenney et al, 2019;L. Wang et al, 2013) as well as interactions between the MJO and other phenomena (Adames et al, 2016) in a future warmer climate.…”

Key regions in the modulation of seasonal GMST variability by analyzing the two hottest years: 2016 vs. 2020

“…Next, the mechanisms for skillful S2S prediction are not clear enough. For instance, the relationship between the stratospheric polar vortex and tropospheric circulation, the timing of final warming events, the teleconnections with MJO, the breakouts of extreme events, have constraints on the model's ability to capture the S2S surface temperature forecasts (Butler et al 2019, Jenney et al 2019, Miller and Wang 2019, Xiang et al 2019, Lang et al 2020. The initial errors and model errors (e.g.…”

Introduction to Special Collection: “Bridging Weather and Climate: Subseasonal‐to‐Seasonal (S2S) Prediction”

“…They apply this metric to daily observational circulation and sensible weather data to identify the locations where the MJO has the most impact in winter. Jenney, Nardi, et al () also apply the STRIPES metric in other seasons and demonstrate the potential to use MJO information for skillful S2S prediction throughout the year.…”