El Nio…Its Origins and Its Effects

In an average year, the trade wind blows from east to west across the equatorial Pacific, and that transports a lot of very warm water toward the western rim of the Pacific Ocean, which is where the vast majority of the rain and thunderstorm activity ends up occurring during an average year.

When we have an El Nio, the trade wind can weaken or reverse direction, and when it does that, the warmest water then pools in the central Pacific, which is what we have this year. When it does that, all the rain and thunderstorm activity over the central Pacific can then affect California.

This graphic shows the difference between an average temperature of the Pacific Ocean and what we have during this El Nio. the darkest red colors you see signify 5 to 7 degrees Fahrenheit above average temperatures. That’s a lot of heat for a large area, and that can create big changes in our weather.

This El Nio began in the spring of 2015, but many in California didn’t realize that because we don’t feel the effects of it until the following winter. It did bring a lot of drought and wildfire as well as a lot of heat to southeast Asia and Australia during the summer, and then when winter came around, those effects became more intensified for Asia, we had warmer weather for the Pacific Northwest, and that’s when the southern U.S. has the best chance for some wetter weather.

The latest outlooks for the month of February as well as the rest of winter were just released, and we have been monitoring the monthly and seasonal outlooks all year long. The latest outlook still gives California a better chance for above average rain for the month of February, but it does appear that the El Nio for this season has already reached its peak.

Then as we look at February, March and April, we still have that same signature… above average precipitation is where we have the best odds, but it is not a guarantee unfortunately. It’s very important that we receive all the rain and mountain snow that we can during this winter, because not only does this El Nio not appear to last into late next year, we actually appear to have a La Nia forming by next winter.

Here’s the outlook for February, March and April…we have a better chance for below average rain and snow. Keep in mind this is a broad-brush forecast, we cannot directly derive amounts of rain for individual cities or counties with a forecast like this. It just gives us a good broad-brush look at the regional and national effects.

You can rest assured that the First Alert Weather team will continue to monitor El Nio during this year as well as all of next year’s weather and beyond to see how our drought is going to progress and if we can finally get some rain where we need it the most here in the Golden State of California.