Wondering how the record-setting El Niño of 1997-1998 compares to this year? NASA released a week-by-week animation of the two events, showing how the extent and intensity of the abnormally warm ocean water changed over time.

Today NOAA updated their outlook for El Niño, calling for at least a strong event and possibly a record strong event by wintertime. At the very least, it looks like this year’s El Niño will be the strongest since 1997-1998. That could have dramatic impacts on our winter weather across the U.S., including more rain for California, and possibly a warm winter for the Mid-Atlantic.

The video shows satellite measurements of sea surface height, which scientists can use as a proxy for temperature. This year’s El Niño exploded across the equatorial Pacific Ocean in March and April, while the 1997 version was still getting its legs. Interestingly, sea surface temperature in the far eastern Pacific is running closer to average so far this year, with the warmest water focused in the central Pacific. But in 1997, the warmest water sloshed very far east through the end of the year, right up against coastal South America.

It will be interesting to see how El Niño continues to morph this year, since some studies have shown that it only takes slight variations in strength and extent to change the way it affects our weather.