May 2022 Climate Forecast Discussion
May 2022 Climate forecast Discussion for Jun-Aug through Sep-Nov 2022
**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 1991-2020.
In April 2022, the equatorial sea surface temperatures (SSTs) in the central-eastern tropical Pacific Ocean were below average, and tropical Pacific atmosphere remained consistent with La Niña conditions. The CPC/IRI ENSO forecast from early-May indicates that La Niña is likely to persist during summer and fall in the Northern Hemisphere with 69% chance in Jun-Aug 2022, weakening during Jul-Sep and Aug-Oct, while strengthening slightly thereafter. Four out of the five models used in IRI’s seasonal climate forecast, predict cooler than average SSTs over the eastern tropical Pacific and a continuation of the current La Niña episode. GFDL-SPEAR, one of the five models used here, indicates ENSO-neutral conditions for the next few months, before reverting back to La Niña later in the forecast. This has significant impacts on the seasonal forecasts of precipitation and temperature across the globe. The tropical Atlantic Ocean does not exhibit significant SST anomalies, while a gradually strengthening negative dipole in the Indian Ocean is evident during the forecast period.
The forecasts show moderate probabilities of below-normal precipitation in the Northwest United States, southern South America, and Turkey in Jun-Aug, weakening during rest of the forecast period. Increasing probabilities of below-average precipitation are forecast for the east African region during the Aug-Oct and Sep-Nov seasons, together with weak probabilities of below-normal precipitation over scattered parts of southern and central Africa during the forecast period. Enhanced probabilities of above-normal precipitation are forecasted for the African Sahel, many parts of the Asian and some parts of the central American regions during the forecast period. Very high probabilities are also forecasted over most of the Maritime continent, and Australia during the forecast period, with increasingly high probabilities toward the end of the forecast period.
High probabilities of above-normal temperatures are forecast over the majority of land areas, while moderate probabilities of below-normal temperatures are forecast for African, and Asian monsoon regions during the forecast period. Weak probabilities of below-normal to near-normal temperatures are also forecasted over parts of central and northwestern regions of South America, southern South Africa, and Australia during the forecast period.