August 2022 Climate Forecast Discussion

Aug 2022 Climate Forecast Discussion for Sep-Nov through Dec-Feb 2023

Note: The IRI seasonal forecasts of precipitation and temperature issued this month are based on an objective calibration procedure that combines the NCEP-CFSv2, CanSIPS-IC3, COLA-RSMAS-CCSM4, and GFDL-SPEAR, and NASA-GEOSS2S models. The climatological base period for normal is 1991-202020.

In July 2022, the equatorial sea surface temperatures (SSTs) in the central-eastern tropical Pacific Ocean remained consistent with weak La Niña conditions (NINO3.4 index value in July 2022 was -0.68). According to the early-August CPC ENSO forecast, La Niña is likely to persist until boreal winter 2022-23 with 60% probabilities, which would be the first triple-dip event of the 21st century. The prolonged La Niña SST pattern in the tropical Pacific does impact the associated seasonal climate forecast. In addition, a negative Indian Ocean Dipole Mode and weak below-average SST in the Atlantic Ocean are forecasted for all four overlapping 3-month forecast seasons (slightly weaker values during the last two seasons, i.e. Nov-Jan and Dec-Feb).

During Sep-Nov and Oct-Dec 2022, the forecasts indicate moderately increased probabilities of below-normal precipitation in southern South America, over and around southeast US and Mexico, East Africa, western Türkiye, Central Southwest Asia, parts of Madagascar. These values weaken slightly during Nov-Jan and Dec-Feb, 2023. Below-normal precipitation is also forecasted for Nov-Jan and Dec-Feb 2023 over western and northeastern China. High probabilities of above-normal precipitation are forecasted over most of Australia and much of the Maritime Continent, during first three overlapping seasons, with somewhat weakened values during Dec-Feb, 2023. Gradually increasing values of above-normal precipitation are forecasted over several northern south American and southern African regions with highest values in Dec-Feb 2023.

High probabilities of above-normal temperatures are forecast over the majority of land areas during the forecast period. During Sep-Nov 2022, moderate probabilities of below-normal temperatures are forecasted over African Sahel, southern Pakistan, and southern India, gradually weaking in Oct-Dec, Nov-Jan and Dec-Feb, except for the African Sahel which show above-normal values in Nov-Jan and Dec-Feb. Over Australia enhanced probabilities of below-normal temperatures are forecast throughout the forecast period. Weak probabilities of below-normal temperatures are also forecasted over Alaska during Dec-Feb, 2023.