Australian Bureau of Meteorology ENSO/IOD Update

Tropical Troposheric Upper Trough Slows Down Tropical Season
08/16/2019, 10:24 am EDT
North Atlantic Tropics Showing Signs of Life
08/23/2019, 10:37 am EDT
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Neutral ENSO ahead BUT with a Modoki-like character for northern hemisphere autumn. Indian Ocean Dipole forecasts indicate an immensely intense positive phase.

ENSO & IOD Outlook/Update

Discussion: El Nino southern oscillation is neutral and forecast to remain so into early 2020 (Fig. 1). However, the distinct lingering warm pattern near the Dateline compared to cooler SSTA in the eastern equatorial Pacific represents an El Nino Modoki character to the current ENSO condition likely to last another few months. Other global SSTA forecast models maintain this signature into early next year (Fig. 2). The Modoki-like signature is important to the North America climate forecast due to its (winter) bias of a prevailing (mild/dry) upper ridge over western North America and downstream (cold/snowy) trough in eastern North America.

Fig. 1: The Australian Bureau of Meteorology Nino34 SSTA forecast through next February indicates neutral ENSO. However, the Bureau Nino4/Nino3 outlooks indicate a weak El Nino Modoki character through November.

Fig. 2: The NCEP CFS V2 global SSTA outlook indicates an El Nino Modoki-like SSTA signature lingering in the central/east equatorial Pacific for Quarter 1 of 2020.

The positive phase of the Indian Ocean Dipole remains intense and is forecast to gain strength over the next month or 2 and last through 2019 before weakening early next year (Fig. 3). +IOD is a drought-producer (or enhancer) for southern and central Australia. The +IOD favors a drier pattern in Indonesia and wet climate for the western half of India.

Fig. 3: The Australian Bureau of Meteorology Indian Ocean Dipole forecast through next February indicates an intense positive phase the next few months weakening early next year.