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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 2020
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 2020 Climate Forecast Discussion

September 2020 Climate Forecast Discussion for Oct-Dec through Jan-Mar

The SST forecast is for weak-to-moderate La Niña conditions to continue in the central and eastern tropical Pacific through JFM, accompanied by warm SSTs in the North Pacific and North Atlantic. SSTs are already cool in the eastern and central Pacific, and are forecast to remain cool through the forecast period, but SSTs in the tropical Indian and Atlantic Oceans are forecast to relax towards neutral. Warmth in the North Atlantic and Pacific oceans is forecast to persist through JFM.

Precipitation forecasts reflect the SST forecast with many canonical La Niña teleconnections. In OND enhanced probabilities of below normal precipitation are forecast for Mexico and the Southern US, Southeast South America, the Horn of Africa, Southeast Asia, and Southeast China. Enhanced probabilities of below normal precipitation persist in the Southern US through JFM, but only persist in Southeast South America through NDJ.

Enhanced probabilities of above normal precipitation are forecast for Central America, the Maritime Continent, and, to a lesser extent, Australia and Southern Africa. Probabilities of above normal precipitation increase in Northern Central America through DJF and persist into JFM.

A strongly enhanced probability of above normal temperatures accompanies the probability of below normal precipitation in the Southwest United States in OND through JFM. Temperatures are likewise forecast to be above normal in Greenland, Canada, and Northeast Russia. A slightly enhanced probability of below normal temperatures is forecast for southeast Australia in OND, and in the US Midwest in DJF and JFM.

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.