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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
May-June-July Issued April 2017
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

April 2017 Climate Forecast Discussion

April 2017 Climate Forecast Discussion for May-Jul through Aug-Oct

The SST forecast shows El Niño development by Jul-Sep, reaching moderate strength by the fourth and final running forecast season of Aug-Oct. A positive Indian Ocean Dipole exists throughout the four forecast seasons, and becomes somewhat stronger by the fourth season. The tropical Atlantic maintains near to slightly above average SST during all four seasons.

Slightly enhanced probabilities for below-normal precipitation are predicted in far northern South America during May-Jul, progressively strengthening and expanding to include more of northern South America by Jul-Sep, and persisting into Aug-Oct. A similar scenario of strengthening chances for below-normal is predicted for Indonesia beginning in Jun-Aug, and for eastern Australia over the course of all four forecast periods. By Aug-Oct season, the region leaning toward below-normal in eastern Australia expands northward to join Indonesia.

A tendency toward above-normal temperature is predicted in a general manner over much of the globe for all four forecast seasons, with a few exceptions such as a small region in west-central interior North America, straddling the U.S./Canadian border, during the first two seasons. Probabilities for above-normal are strongest in Greenland and northeastern Canada during the second, third and fourth seasons, and in varying parts of Eurasia and South America during the course of the four 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.