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07/12/2018, 7:16 am EDT

Australia Season 1-3 Ahead Climate Outlook

Will the Australian Drought Become the Worst in History by late year? Executive Summary: The Climate Impact Company season 1-3 ahead forecast for Australia is adjusted for impacts on global climate by El Nino Modoki. There is no question that harsh drought already in-place across much of Australia is likely to worsen brought about by a drier-than-normal climate engineered by an evolving El Nino with a warm bias in the ocean tilted toward the central Pacific. Climate discussion:  A somewhat recent discovery of an infrequent version of an El Nino episode known as El Nino Modoki is becoming a more likely scenario for the next 1-3 to as many as 9 months ahead according to the Japan Agency for Marine-Earth Science and Technology (Fig. 1) and various global SSTA forecast models governing the most likely climate patterns around the globe. Fig. 1: El Nino-Modoki Index forecast by the Japan Agency for Marine-Earth Science and Technology indicates a weak Modoki ahead for 2018-19. To estimate a historical precedent of El Nino Modoki regimes on global climate analog years are chosen. El Nino Modoki occurred in 2002-03, 2004-05 and 2009-10 (Fig. 2). There are other El Nino Modoki episodes prior to the 3 listed however they occurred when another important mode of climate variability, the Atlantic multi-decadal oscillation (AMO) was in the cool phase (Fig. 3). Fig. 2: Analog years comparing cool Nino12 SSTA and warm Nino34 characteristic of El Nino Modoki and the last 3 months of 2018. Fig. 3: Analog years are chosen from the past 20 years when the Atlantic multi-decadal oscillation has been in the warm phase. Outlooks: A simple El Nino Modoki analog forecast of temperature and precipitation anomalies is indicated for JUL/AUG, SEP/OCT/NOV and DEC/JAN/FEB 2018-19. The outlooks are a confident first estimate of what to expect in each sector of the globe as to general climate conditions inspired by this unique El Nino scenario. Regional influences such as soil moisture plus regional SSTA regimes outside of the tropics can modify the El Nino Modoki climate. In Australia the concern is lack of precipitation for the remainder of 2018 intensifies already widespread drought (Fig. 4). Fig. 4: End of June 2018 soil moisture anomalies across Australia identify wide areas of drought. July/August 2018: Warm SSTA in the subtropics and tropics east and northeast of Australia correlate to a warmer-than-normal mid-to-late winter across Australia (except for the west coast). The precipitation outlook favor continued dry climate across Eastern Australia causing drought conditions to worsen. To the north, Indonesia is also dry. There are no anomalous wet regions forecast across Australia through late winter. Fig. 5-6: An El Nino Modoki climate pattern featuring temperature and precipitation anomalies for Australia for JUL/AUG 2018. SEP/OCT/NOV 2018: The spring 2018 outlook is dry! Much of the Australian drought condition departing the winter 2018 season will worsen during spring. The driest part of the outlook is across the eastern half of Australia where subtropical ridging is strongest. Precipitation can be near normal across Western Australia but not enough to reverse drought. The temperature outlook for spring is warmer-than-normal with strongest anomalies in the southeast Australia crop sector. Fig. 7-8: An El Nino Modoki climate pattern featuring temperature and precipitation anomalies for Australia for SEP/OCT/NOV 2018. DEC/JAN/FEB 2018-19: The summer 2018-19 forecast is made with below average forecast confidence due to the uncertainty of ENSO at this long-lead. Probabilistic forecasts are much drier and indicate potential for the worst drought in history across Australia for next summer. The constructed analog forecast is less harsh identifying a wet zone across northeast Australia. However, drought areas across much of the remainder of the continent remain harsh especially in the Southeast and parts of the western continent. Fig. 9-10: An El Nino Modoki climate pattern featuring temperature and precipitation anomalies for Australia for DEC/JAN/FEB 2018-19.