Physics News Update: El NinoWeather in a warmer world will cause a decrease in the number of frost days in the southwestern states, an increase in precipitation intensity in southeastern states, and an increase in heat-wave intensity in the southern tier of states, according to a new study. The study looks at the weather impact of El Nino events on weather extremes in North American if, as is often predicted, global warming raises temperatures by a degree or two in coming decades.