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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
June-July-August Issued May 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

May 2017 Climate Forecast Discussion

May 2017 Climate Forecast Discussion for Jun-Aug through Sep-Nov

The SST forecast shows development of weak El Niño conditions by Jun-Aug, growing slightly to reach weak/moderate strength by the fourth forecast season of Sep-Nov. A positive Indian Ocean Dipole exists throughout the four forecast seasons, becoming slightly 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 parts of northern and central South America during Jun-Aug and Jul-Sep, settling to mainly northern South America during Aug-Oct and Sep-Nov. An enhanced likelihood for below-normal is predicted for Indonesia and eastern Australia during Jun-Aug, becoming stronger during the last three forecast periods. A tilt of the odds toward below normal is also forecast for central Africa for the final season of Sep-Nov.

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 northern North America during the last two seasons. Probabilities for above-normal are strongest in Greenland during all four forecast seasons, expanding to northern North America during the third and especially fourth season. The tendency toward above-normal temperature becomes progressively stronger between the first and fourth forecast season, covering much of Asia, northern Africa, Australia and central and northern South America by Sep-Nov.

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.