Current and future U.S. weather extremes and El Niño

A global coupled climate model representative of the current generation of models is shown to simulate most first order aspects of El Niño events, their teleconnections over North America, and the associated observed patterns of extremes in present-day climate. Future El Niño teleconnection patterns over the U.S. are projected to shift eastward and northward due in part to the different midlatitude base state atmospheric circulation in a warmer climate. Consequently, projections for the changes in the patterns of extremes over the U.S. during future El Niño events include: decreases of frost days over the southwestern U.S expand northward and eastward; increases in intense precipitation in the SW U.S. expands eastward and areas in the SE U.S. become stronger; and decreases of heat wave intensity over much of the southern tier of states turn to increases.