Jul 2022 Climate Forecast Discussion for Aug-Oct through Nov-Jan 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, GFDL-SPEAR and NASA-GEOSS2S models. The climatological base period for normal is 1991-2020.
In June 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 June 2022 was -0.68). In the early-July CPC/IRI ENSO forecast, La Niña is likely to persist during the rest of the boreal summer, fall and early winter with probabilities ranging from 60 to 66%. The sustained La Niña SST pattern forecasted in the tropical Pacific does impact the associated seasonal climate forecast. In addition, a negative Indian Ocean Dipole is forecasted for all four seasons, most strongly during the first three seasons (Aug-Oct, Sep-Nov, Oct-Dec, 2022). Near-average SST is forecasted for the north and south tropical Atlantic during Aug-Oct 2022, while a weak below-average SST (gradually increasing) is forecasted during the other three seasons (Sep-Nov, Oct-Dec 2022, and Nov-Jan 2023).
In Aug-Oct 2022, the forecasts indicate weak to moderate probabilities of below-normal precipitation in southern South America, East Africa, Türkiye, and Central Southwest Asia, which strengthen over the remainder of the forecast period. Below-normal precipitation probabilities are forecasted over and around southeast US and Mexico during Sep-Nov 2022, with gradually intensifying below-average probabilities in Oct-Dec 2022 and Nov-Jan 2023. Below-average precipitation is also forecast for Nov-Jan 2023 over western and northeastern China. During Aug-Oct and Sep-Nov 2022, high probabilities of above-normal precipitation are forecasted over most of Australia and much of the Maritime Continent, with gradually decreasing values during Oct-Dec 2022 and Nov-Jan 2023. Forecasts indicate a moderate probability of above-normal precipitation in Aug-Oct, and Sep-Nov 2022, especially in northern South America, the Sahel region of Africa, the southwest Arabian Peninsula, many regions of South Asian monsoon, and Southeast Asia. A moderate to weak probability of above-average precipitation is forecast for most of the Indian Peninsula, southeast Asia, and central Brazil during Oct-Dec of 2022, while, South Africa is expected to experience above-normal precipitation in Nov-Jan 2023.
High probabilities of above-normal temperatures are forecast over the majority of land areas during the forecast period. However, moderate probabilities of below-normal temperatures are forecast for the African Sahel, southern Indian Peninsula, and some parts of southwestern Africa and over much of Australia during Aug-Oct 2022, which weaken during rest of the forecast period except over Australia where enhanced probabilities of below-normal temperatures are forecast throughout the forecast period. Weak probabilities of below-normal temperatures are also forecasted over mainland southeast Asia during Oct-Dec, 2022.
