December 2022 Climate Forecast Discussion

Dec 2022 Climate Forecast Discussion for Jan-Mar through Apr-Jun 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 1991-2020

In November 2022, the equatorial sea surface temperatures (SSTs) in the central-eastern tropical Pacific Ocean remained cooler than normal, exhibiting persistent La Niña conditions (NINO3.4 index value in November 2022 was -0.93C). According to the early-December CPC ENSO forecast, La Niña and ENSO-neutral conditions are equally likely (50/50) during Jan-Mar 2023, with ENSO-neutral becoming the most likely category in subsequent three seasons (more than 70% chance in Feb-Apr, Mar-May, and Apr-Jun, 2023). The prolonged La Niña SST pattern in the tropical Pacific does impact the associated seasonal climate forecast, described below. No strong SST anomalies are present in the tropical Indian and Atlantic Oceans in both observations and the forecast.

In Jan-Mar 2023, enhanced probabilities of below-normal precipitation are forecast for northwest Mexico and the southwestern US; these persist through the rest of the forecast period with gradual northward movement and declining values. Weakly enhanced probabilities of below-normal precipitation are forecast over parts of southeast Brazil/Uruguay and southern Australia during Feb-Apr onwards. Moderately enhanced probabilities of above-normal precipitation are forecast for northern South America, the Philippines, and southern Africa during Jan-Mar, Feb-Apr, and Mar-May 2023. In Feb-Mar 2023 and onwards, weakly enhanced probabilities of above-normal precipitation are forecast over parts of Southeast Asia and central China.

For temperature, increased probabilities of above-normal temperatures are forecast over many land areas, becoming particularly widespread from March-May onwards; these areas include the Maritime Continent, Asia, the Middle East, large parts of the African continent (northern parts), much of southern and southeastern US, eastern Canada, and southern South America during Jan-Mar and Feb-Apr 2023. Moderate probabilities of below-normal temperatures are forecasted over western Canada, northern South America, South Africa, and most of Madagascar, during Jan-Mar 2023 and onwards, although weakening gradually toward the end of the forecast period (except for Madagascar).