Although 2013 is not showing signs of the weather patten El Niño’s mischief, in past years El Niño, or the Child, has been a major brat when he played with winter weather. During some El Niño years, he toys with the weather more than others, but it was hard to know when he was going to be a problem child. However, a sign that preceded those El Niño temper tantrums recently was observed by National Oceanic and Atmospheric Administration meteorologists.
When clouds in the eastern equatorial Pacific Ocean are higher and colder, they reflect less infrared radiation, or heat, back into space. Satellites have been monitoring those changes in heat reflection, or outgoing longwave radiation, for decades. NOAA scientists observed that during El Niño when there was a drop in infrared radiation reflection, there also was a higher probability of weather anomalies in the United States.
“By sorting El Niño events into two categories, one with outgoing longwave radiation changes and one without, forecasters may be able to produce winter seasonal outlooks with more confidence than previously thought possible,” study co-leader NOAA’s Ed Harrison said in a press release.
El Niño winters are warmer and drier for much of the northern U.S., while bringing cooler and wetter weather to the southern U.S. When El Niño is playing rough, those weather extremes can mean intense storms or droughts.
The NOAA-led study was published in the Journal of Climate.
IMAGE: El Niño, warmer than average waters in the Eastern equatorial Pacific, shown in orange on the map, affects weather around the world. (NOAA Visualization Lab)