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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 2018
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 2018 Climate Forecast Discussion

April 2018 Climate Forecast Discussion for May-July through August-October

The SST forecast shows neutral ENSO conditions for the initial May-Jul season, transitioning to progressively warmer conditions with increasing lead time, reaching a borderline or weak El Nino level by Aug-Oct. Much of the subtropical and extratropical North Pacific and North Atlantic SST, and the SST in much of the mid-latitude Southern Hemisphere, is predicted to be above average during all four forecast seasons, with the exception of the very high latitude Pacific waters in the Southern Hemisphere, which are predicted to be below average, especially for May-Jul and Jun-Aug. A near-neutral Indian Ocean Dipole is predicted for May-Jul through Aug-Oct. Near-average SST is predicted for the tropical Atlantic for May-Jul through Aug-Oct.

Enhanced probabilities for below-normal precipitation are predicted for part of northern South America from Jun-Aug through Aug-Oct and for much of Central America for all four forecast seasons but most strongly for Jun-Aug and Jul-Sep. A tilt of the odds toward below-normal is also predicted for Indonesia for May-Jul through Aug-Oct, for central southeast Asia as well as central Chile mainly for May-Jul and Jun-Aug. Enhanced chances for above-normal precipitation are forecast for parts of the African Sahel for Jun-Aug through Aug-Oct, for parts of central India, Nepal and adjacent Tibetan China for May-Jul through Jul-Sep, northwestern Africa for Jul-Sep and Aug-Oct, and far northern North America for May-Jul through Jul-Sep.

Enhanced probabilities for above-normal temperature are predicted for Greenland, parts of Asia, Europe, northern Africa and central North America from May-Jul through Aug-Oct. A tilt toward above-normal is also forecast for mainly northern and southeastern South America for Jul-Sep and Aug-Oct, and for mainly northern Australia for May-Jul and again later in Aug-Oct. A tilt of the odds toward below-normal temperature is forecast in northeastern Asia and northwestern North America for May-Jul, and for central India for May-Jul and Jun-Aug. The tilt for below normal appears again in northern and/or northeastern Asia for Jul-Sep and Aug-Oct, and in northern North America for Jul-Sep. An enhanced likelihood for near-normal temperature is predicted for small parts of northeastern South America for May-Jul through Aug-Oct, and for central Africa mainly for Jun-Aug.

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.