As promised yesterday, a robust convection phase of the Madden Julian oscillation (MJO) shifts into the tropical West Pacific just-after mid-month causing a warming influence to develop on the U.S. climate. Snow cover slows the warm-up in the medium range but note the mega-cluster ensemble “most likely” upper air forecast dissipates the polar vortex and creates high pressure across much of the U.S. in 15 days.

Emergence of a marine heat wave (MHW) east of Australia extending to the east of New Zealand coupled with another elongated MHW across the central and southeast Indian Ocean are well-correlated to high pressure ridge areas. In-between the ridge areas, a low-pressure area has spawned over the central coast of South Australia. The upper trough combined with the warmer SSTA off the East Coast is causing excessive rainfall in Eastern Australia so far during meteorological summer 2023-24.

AI-driven weather forecast models show strong achievement in reducing the amount of time required to create a weather forecast, as the models are not driven by the computationally demanding fundamental equations of the atmosphere like NWP. However, like NWP, weather forecasts generated by AI-driven models struggle with forecast accuracy at longer lead times, due to the iterative approach of weather forecasting to atmospheric variables that are chaotic and stochastic. 

A comparison between the regional SSTA-based Climate Impact Company constructed analog 500 MB forecast for the northern hemisphere for January 2024 with the ECMWF outlook reveals generally similar characteristics for mid-winter.