Will it be an El Niño winter or not? Just a month ago, conditions in the Pacific Ocean seemed favorable for the formation of the weather phenomenon later this year. But a new projection seems to cast doubts on that. According to data from the Climate Prediction Center, El Niño development has slowed over the past month. In the equatorial Pacific Ocean, where El Niño is born, conditions are said to be largely “neutral.”

The latest prediction is a change from the past few months, when computer forecasting models indicated that El Niño would strengthen to “moderate” by late 2012. But with the recent slowdown in development, the models are now indicating borderline “neutral” to “weak” conditions forming at year’s end. However, the Climate Prediction Center’s official forecast still leaves room for El Niño to strengthen in the next few months.

El Niño is formed when water across the equatorial Pacific Ocean is warmer than average. The resulting weather patterns often mean a rainy winter in Arizona.