Blame Those Troublemaking MJOs

January 29, 2016
Hurricane Isaac 2012

Are you already tired of the Atlantic hurricane season?

Now that we have some El Niño conditions in the Tropical Pacific, aren’t things supposed to quiet down?

Sorry, thanks to the troublemaker of the oceans, the Madden Julian Oscillation or MJOs, we still are going to see more storms.

The oceans are full of climate patterns. Usually the giant El Niño shapes the weathers in the tropics.

However, when the El Niños are very new and weak, like now, other patterns can dominate.

That’s all the MJOs need to cause trouble.

Expand below picture.

MJOs flow through the tropics, causing storms and droughts. Source: Browning Newsletter

MJOs are small ocean/wind patterns that drift around the equator. Each pulse lasts for a few weeks at a time. First you have quiet trade winds for a few weeks. The ocean below becomes still and sun warmed. (This warm water is called a Kelvin wave.) Then it is followed by strong winds that toss the seas, cool the ocean and cause storms. Warm, then cool, dry, then stormy – that’s the pattern of the MJOs as they flow around the tropics.

If MJOs are strong, this can cause some real problems. For example, India was supposed to be in its wet monsoon season last July. A drying MJO drifted over India and the monsoon failed. Desperate Indian farmers lost 22% of their rainfall. When they tried to use electricity to irrigate the fields, it caused a massive blackout that left 700 million people without power.

Expand below picture.

See the MJO pulses around the tropics. The MJOs are kicking up a storm in the middle of the Atlantic. Source: NOAA

Now the stormy phase of a MJO is in the middle of the Atlantic. El Niños may be suppressing hurricanes, but the MJO is literally kicking up a storm. It has helped start Isaac, Joyce, Kirk, Leslie and Michael. It is expected to linger and cause more storms and more mischief.

The El Niño conditions are trying to quiet our storm season down. But if we have any more storms, you know who to blame. It’s those troublemaking MJOs.

About This Blog

The column, “Weather Whispers,” is authored by James Garriss and Evelyn Browning Garriss, historical climatologists and weather addicts!  Whether you enjoy the science of weather or the fascinating folklore or just fun weather phenomena, it’s probably covered by these weather watchers!