El Nino for the Navy

How does an El Niño and La Niña compare to a normal scenario?

a. El Niño
El Nino 3-D schematic

b. Normal scenario
Normal schematic

c. La Niña
La Nina schematic

Comparison of mean jetstream paths
Note that the location of the jetstream is influenced by the location of the convection, e.g. the main mean jetstream for La Niña starts to the left of the normal scenario. These are the teleconnections to our mid-latitude weather.

The following graphics show the temperature distribution in the Pacific Ocean for a La Niña, a normal year, and an El Niño.
La Niña
Dec. 1988
La Nina sea surface temperature
Dec. 1990
normal sea surface temperature
El Niño
Dec. 1997
El Niño sea surface temperature

These graphics were taken from the El Niño theme page (NOAA)