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.
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.