02/08/2024, 2:29 pm EST

Australia Season 1-4 Ahead Forecast: Australia climate pattern likely to flip later this year as La Nina and -IOD regenerate.

Executive Summary: The Australia season 1-4 ahead forecast is updated valid for meteorological autumn 2024 through meteorological summer 2024-25. The forecast is based primarily on a shift in ENSO from El Nino to La Nina and a flip in the IOD pattern toward negative phase. Marine heat waves continue either side of Australia. Forecast highlights include strengthening northwest continent drought through the remainder of the 2024 warm season, a wet pattern-change for winter ahead across Eastern Australia, and a wet summer 2024-25 season except drier/hotter than normal across southeast continent. Climate: Meteorological summer 2023-24 (so far) has featured expected anomalous heat for most of the continent (Fig. 1). Unexpected is the persistent weak upper trough on the central south coast of Australia responsible for igniting heavy rain across the eastern 40% of the continent (Fig. 2). The summer 2023-24 climate outlook issued last September projected the anomalous heat (Fig. 3) but due to El Nino, favored a drier regime in North and East Australia (Fig. 4). The unexpected rain across East Australia is due to large marine heat waves (MHW) southwest and east of the continent (Fig. 5) where subtropical high pressure ridge areas formed aloft. In-between the two high pressure areas, the rain producing trough formed on the Australia south coast. MHW’s either side of Australia have increased their strength and aerial coverage during recent years and are affecting established ENSO climate. Soil moisture conditions reveal drought a Western Australia (Fig. 6) drought caused by positive phase of the Indian Ocean dipole (+IOD). There is a recent tendency for developing dry soil in Northeast Queensland. The tropical SSTA forecast for later this year (JUL/AUG/SEP) reveals a potential COMPLETE change featuring both the evolution of La Nina and -IOD (Fig. 7). The Climate Impact Company constructed analog maintains La Nina through 2025 (Fig. 8). The season 1-4 ahead climate forecast for Australia is based on decelerating El Nino and +IOD through the next 3 months and evolution of La Nina and -IOD for mid-to-late year. Fig. 1-4: The Australia temperature and precipitation anomaly observations for meteorological summer 2023-24 so far (top) compared to the Climate Impact Company forecast issued last September (bottom). Fig. 5-6: The current global SSTA analysis revealing marine heat waves near Australia and the current continental soil moisture anomaly observations.     Fig. 7-8: The NMME global SSTA forecast for JUL/AUG/SEP 2024 and the Climate Impact Company Nino34 SSTA forecast identifying ENSO phase through 2025. MAR/APR/MAY 2024: Meteorological autumn 2024 features additional mostly dry and warmer than normal climate across northwestern continent which maintains a strong drought in that region. Anomalous warmth continues across Eastern Australia and the climate pattern is generally drier than normal near the coast to help accelerate dry soils in that region. The wildcard is March tropical cyclone activity which is favored across Northern Queensland. Fig. 9-10: The Climate Impact Company constructed analog temperature and precipitation anomaly climate forecasts for MAR/APR/MAY 2024. JUN/JUL/AUG 2024: Next meteorological winter features a flip toward and eventually into a La Nina climate. Consequently, Eastern Australia trend is wetter than normal. Parts of the West Coast also shift wetter likely due to a -IOD climate pattern. The northern continent enjoys a warmer than normal winter season while southern continent features periods of cold. Fig. 11-12: The Climate Impact Company constructed analog temperature and precipitation anomaly climate forecasts for JUN/JUL/AUG 2024. SEP/OCT/NOV 2024: Next meteorological spring season brings a cooler than normal climate for much of the continent. Wet climate risk is confined mostly to Queensland. Fig. 13-14: The Climate Impact Company constructed analog temperature and precipitation anomaly climate forecasts for SEP/OCT/NOV 2024. DEC/JAN/FEB 2024-25: The meteorological summer 2024-25 season anticipates a wet climate across Western Australia and most of northern continent where a wetter than normal monsoon develops. The wet climate leaves northwest continent less hot than normal while Southeast Australia is a drier and hotter than normal zone. Fig. 15-16: The Climate Impact Company constructed analog temperature and precipitation anomaly climate forecasts for DEC/JAN/FEB 2024-25.