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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 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

September 2017 Climate Forecast Discussion

September 2017 Climate Forecast Discussion for Oct-Dec through Jan-Mar

The SST forecast shows weak La Nina conditions for Oct-Dec through Jan-Mar, weakening slightly for Jan-Mar. The subtropical North Pacific SST and the SST in many of the other extratropical regions are predicted to be above average during all four forecast seasons. A slightly positive Indian Ocean Dipole is predicted for Oct-Dec through Dec-Feb, weakening for the later seasons. Slightly above-average tropical Atlantic SST is predicted for mainly Oct-Dec and Nov-Jan.

Enhanced probabilities for below-normal precipitation are predicted for Mexico and the southeastern U.S. from Oct-Dec through Jan-Mar, and in part of southeastern South America from Oct-Dec to Dec-Feb. A tilt of the odds toward below-normal is also forecast for part of southwestern Asia for Oct-Dec, for part of east coastal Asia from Nov-Jan to Jan-Mar, and much of Greenland for Nov-Jan and Jan-Mar. Enhanced chances for above-normal precipitation are forecast for northern South America and for most of Indonesia and parts of eastern Australia from Oct-Dec through Jan-Mar. A tilt toward above-normal is also predicted for northern and northeastern Asia for Oct-Dec and Nov-Jan.

An enhanced probability for above-normal temperature is predicted for Mexico and the southern U.S., as well as much of Asia and northeastern Europe, from Oct-Dec through Jan-Mar. Enhanced probabilities for above-normal are strongest and most widespread in Oct-Dec, when they appear also in much of northern North America, Greenland, central South America and parts of Australia and Africa. A tendency toward below-normal temperature is forecast in portions of mid-latitude North America Dec-Feb and Jan-Mar.

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.