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Published April 24, 2013
Temperature Outlook(May–October 2013)
Data Source(s): NOAA-Climate Prediction Center (CPC)
The seasonal temperature outlooks issued by the NOAA-Climate Prediction Center (CPC) in April call for increased chances that temperatures will be similar to the warmest 10 years in the 1981–2010 period for the three-month seasons spanning May through October (Figures 9a–d). However, the CPC notes that accuracy in the temperature outlooks is lowest in late spring and late fall for the lower 48 states; the highest accuracy is in late winter and summer. These forecasts were based primarily on dynamical models and are largely consistent with decadal trends. Substantial soil moisture deficits over much of the West also are consistent with an increased chance of above-average temperatures during the upcoming three-month seasons. If temperatures are above average for the May–July period, the magnitude of the anomaly is likely to be between 0.6 and 1.5 degrees F in the northern half of Arizona and New Mexico. Seasonal forecasts that span the monsoon also call for warmer-than-average conditions. There is likely less confidence in these forecasts because monsoon precipitation is difficult to project in April, and summers with high precipitation often have cooler temperatures than those with less rain.
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.
For more information on CPC forecasts, visit:
For seasonal temperature forecast downscaled to the local scale, visit:
For IRI forecasts, visit:
Southwest Climate Outlook Staff
- Michael Crimmins, UA Extension Specialist
- Stephanie Doster, Institute of the Environment Editor
- Gregg Garfin, Founding Editor, Institute of the Environment
- Zack Guido, Managing Editor, CLIMAS Associate Staff Scientist
- Nancy J. Selover, Arizona State Climatologist
- Jessica Dollin, CLIMAS Publications Assistant
- Dave Dubois, New Mexico State Climatologist
Please direct your Southwest Climate Outlook comments and suggestions to Zack Guido.
The CLIMAS Web site contains official and non-official forecasts, as well as other information. While we make every effort to verify this information, please understand that we do not warrant the accuracy of any of these materials.... Read full disclaimer