NOAA National Weather Service (NWS) Climate Prediction Center (CPC)
Climate outlooks describe the chances that conditions will be below-normal, near-normal, or above-normal for the outlook period indicated. The U.S. Seasonal Drought Outlook depicts large-scale trends based on subjectively derived probabilities guided by short- and long-range statistical and dynamical forecasts.
Where do these data come from?
Climate scientists base future climate outlooks on current patterns in the ocean and atmosphere. They examine projections from climate and weather models and consider recent trends. They also check historical records to see how much precipitation fell when patterns were similar in the past.