Forecasts
Published June 20, 2011

Temperature Outlook

 (July 2011-December 2011)
Data Source(s): NOAA-Climate Prediction Center (CPC)

The seasonal temperature outlooks issued by the NOAA–Climate Prediction Center (CPC) in June call for increased chances for temperatures to be similar to those of the warmest 10 years of the 1981–2010 period through the spring and summer. These outlooks use the 1981-2010 period to calculate the average, as opposed to the 1971-2000 period which was used until April. This has an impact on trends because the observed warming in the last 10 years is now rolled into the average. For July–September, August–October, and September-November, CPC outlooks call for greater than a 50 percent chance that temperatures will resemble the warmest years in the climatological record in most of Arizona and parts of New Mexico (Figures 9a–c). These forecasts are based in part on decadal trends and low soil moisture present in June. For the October–December period, temperatures have a 40 percent chance of being above average (Figure 9d).

Map of United states depicting the National Temperature forecast
Notes:

These outlooks predict the likelihood (chance) of above-average, average, and below-average temperature, but not the magnitude of such variation. The numbers on the maps do not refer to degrees of temperature.

The NOAA-CPC outlooks are a 3-category forecast. As a starting point, the 1981–2010 climate record is divided into 3 categories, each with a 33.3 percent chance of occurring (i.e., equal chances, EC). The forecast indicates the likelihood of one of the extremes—above-average (A) or below-average (B)—with a corresponding adjustment to the other extreme category; the “average” category is preserved at 33.3 likelihood, unless the forecast is very strong.

Thus, using the NOAA-CPC temperature outlook, areas with light brown shading display a 33.3–39.9 percent chance of above-average, a 33.3 percent chance of average, and a 26.7–33.3 percent chance of below-average temperature. A shade darker brown indicates a 40.0–50.0 percent chance of above-average, a 33.3 percent chance of average, and a 16.7–26.6 percent chance of below-average temperature, and so on.

Equal Chances (EC) indicates areas where no forecast skill has been demonstrated or there is no clear climate signal; areas labeled EC suggest an equal likelihood of above-average, average, and below-average conditions, as a “default option” when forecast skill is poor.

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