On the impact:
For the United States, El Niño can shift the winter track of storms that normally keeps the jungles of southern Mexico and Central America wet and moves them over California and the southern United States. The northern United States, like the Midwest and Northeast, typically see milder winters during El Niño.The South will probably be wetter than normal, and the north warmer. Typically growth picks up a little during an El Niño due to the milder winters in the midwest and northeast.
And on the data:
A key location of the Pacific Ocean is now hotter than recorded in at least 25 years, surpassing the temperatures during the record 1997 El Niño.
Some scientists say their measurements show that this year’s El Niño could be among the most powerful on record -- and even toppling the 1997 event from its pedestal.
“This thing is still growing and it’s definitely warmer than it was in 1997,” said Bill Patzert, climatologist with NASA’s Jet Propulsion Laboratory in La Cañada Flintridge. As far as the temperature readings go, "it’s now bypassed the previous champ of the modern satellite era -- the 1997 El Niño has just been toppled by 2015.”