(August 2013-January 2014)
Data Source(s): NOAA-Climate Prediction Center (CPC)
The seasonal temperature outlooks issued by the NOAA-Climate Prediction Center (CPC) in July 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 August through January (Figures 10a–d). Temperatures are most likely to be 0.6–1.5 degrees F above average in most of Arizona, with slightly lower anomalies expected in New Mexico. The expected temperature anomalies increase from east to west, with the largest in northwest Arizona. The seasonal forecasts presented here are based on statistical and dynamical models and are largely consistent with decadal warming trends.
The monsoon also plays a role in the seasonal forecasts. The highest probabilities for above-average temperatures are found in the southwest corner of Arizona, where monsoon precipitation is low. Monsoon rainfall, where it occurs, often decreases daily temperatures because increased cloud cover accompanies rain. The rains also moisten soils, increasing evaporation that cools the near-surface atmosphere. Increased moisture, however, can also elevate nighttime temperatures.
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.