Home » May 2011 Southwest Climate Outlook » Temperature Outlook
Published May 26, 2011

Temperature Outlook

 (June 2011–November 2011)
Data Source(s): NOAA-Climate Prediction Center (CPC)

The seasonal temperature outlooks issued by the NOAA–Climate Prediction Center (CPC) in May 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 are the first to use the 1981–2010 period to calculate the average, as opposed to the 1971–2000 period. This has an impact on trends because the observed warming in the last 10 years is now rolled into the average. For the June–August and July–September periods, 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 in western New Mexico (Figures 10a–b). These forecasts are based in part on the decadal trends. For forecasts issued for the three- and four-month lead times, temperatures in most of Arizona and the western and southern portions of New Mexico have greater than a 40 percent probability of being similar to those of the warmest 10 years in the climatological record, with some areas having probabilities of greater than 50 percent (Figures 10c–d).

Temperature Outlook
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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