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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
September-October-November Issued August 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

August 2017 Climate Forecast Discussion

Aug 2017 Climate Forecast Discussion for Sep-Nov through Dec-Feb

The SST forecast shows neutral to very slightly coolish ENSO conditions for Sep-Nov, remaining approximately steady through the fourth forecast season of Dec-Feb. The subtropical North Pacific SST and the SST in some other extratropical regions are predicted to be above average during all four forecast seasons. A slightly positive Indian Ocean Dipole is predicted to continue throughout the four forecast seasons. The tropical Atlantic maintains near-average equatorial SST to slightly above average off-equator SST during all four seasons.

Slightly enhanced probabilities for below-normal precipitation are predicted in part of northern South America during Sep-Nov and Oct-Dec, while below-normal is predicted for Nov-Jan and Dec-Feb in parts of southern North America. An enhanced likelihood for below-normal is also predicted for tropical southern Africa for Sep-Nov. A tilt of the odds toward above normal precipitation is forecast for parts of Indonesia for Sep-Nov and Oct-Dec, for northern South America for Dec-Feb, for parts of Europe from Oct-Dec to Dec-Feb, and for parts of northern or northeastern Asia for all four periods.

A tendency toward above-normal temperature is predicted in varying portions of North America, Asia, Australia, and Greenland during most of the four forecast seasons, with weaker warm tendencies in South America, eastern Europe and Africa. Probabilities for above-normal are strongest from Sep-Nov through Nov-Jan in northeastern Asia, northern North America and Greenland. A tendency toward below-normal temperature is forecast in portions of north-central Asia for Dec-Feb.

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.