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Seasonal Forecasts

Temperature and precipitation outlooks on seasonal (multi-month) timescales.

Forecast

Current seasonal temperature and precipitation outlook maps and discussion. Released on or about the 15th of each month.

Using the forecast maps

Use the controls above each map to choose what it shows. On the seasonal page you can pick the forecast Source, the Type (precipitation or temperature) and the date the forecast was issued. On the subseasonal page you pick the Type, then the year, month and day of issue. The map updates as soon as you change a setting. The box of buttons on the map switches between the forecast periods in that issuance: target seasons on the seasonal map, forecast periods on the subseasonal map. The title changes to match the period you pick. You can zoom with the scroll wheel or the +/– buttons and drag to move around the map. Download PNG saves the period currently shown as an image, with its title and legend.

CCSR/IRI NMME Multi-Model Probability Forecast for Precipitation for
October-November-December Issued September 2021
Probability (%) of Most Likely Category
Below Normal
40
45
50
60
70+
Normal
40+
Above Normal
40
45
50
60
70+
Dry Season (No Forecast) Equal Odds

September 2021 Climate Forecast Discussion

Sep 2021 Climate Forecast Discussion for Oct-Dec through Jan-Mar

Note: The IRI seasonal forecasts issued this month are based on the NCEP-CFSv2, CanSIPsv2, and COLA-RSMAS-CCSM4, and GFDL-SPEAR models. Current month forecast also consider the new normal period 1991-2020.

The sea surface temperature (SST) and most atmospheric indicators in the tropical Pacific are currently neutral. However the SST forecasts of the models used in this seasonal climate forecast predict a re-emergence of cool SST anomalies and enhanced likelihood of a second La Niña event (5 consecutive overlapping seasons, according to NOAA’s definition). The La Niña forecasted in the coming seasons does impact the associated seasonal climate forecast. The strongest Atlantic Niño event ever observed has weakened, as has the negative Indian Ocean Dipole, and these two potential drivers are predicted to return to the neutral state in the coming seasons.

For temperature, the Oct-Dec and Nov-Jan forecasts favor above-normal temperatures over most land areas, with particularly enhanced probabilities over Maritime Continent, South Asia, large parts of African continent, much of North America, eastern Canada, and southern South America. For the last two seasons (Dec-Feb and Jan-Mar), the temperature forecast over most of these regions show weakened likelihood for above-average conditions, as confidence typically decreases with forecast lead time. In Oct-Dec, enhanced probabilities of below-normal temperatures are forecasted for much of Australia except its northern coasts, and some parts of central Brazil, tending to diminish in the subsequent seasons.

Citation

Kirtman, B., D. Min, J. Infanti, J. Kinter, D. Paolino, Q. Zhang, H. van den Dool, S. Saha, M. Mendez, E. Becker, P. Peng, P. Tripp, J. Huang, D. DeWitt, M. Tippett, A. Barnston, S. Li, A. Rosati, S. Schubert, M. Rienecker, M. Suarez, Z. Li, J. Marshak, Y. Lim, J. Tribbia, K. Pegion, W. Merryfield, B. Denis, and E. Wood, 2014: The North American Multimodel Ensemble: Phase-1 Seasonal-to-Interannual Prediction; Phase-2 toward Developing Intraseasonal Prediction. Bull. Amer. Meteor. Soc., 95, 585–601, doi: 10.1175/BAMS-D-12-00050.1.