El Niño could shake up weather patterns later this year
Thursday, March 6, 2014, 4:23 PM -
On Thursday, the National Oceanic and Atmospheric Administration (NOAA) issued an official El Niño watch, predicting that ENSO (El Niño Southern Oscillation) neutral conditions -- affectionately nicknamed La Nada -- will continue through the spring season.
El Niño is a large-scale global pattern event. It is defined as a band of anomalously warm ocean water that is accompanied by high air surface pressure in the western Pacific.
When the average sea surface temperatures in the eastern Pacific are 0.5°C or above for three consecutive months, El Niño conditions are declared. This has an impact on the positioning of the jet stream in the Northern Hemisphere which in turn impacts weather patterns.
"This often times means wetter than normal conditions for the west coast of North America, specifically State-side," says Weather Network meteorologist Dayna Vettese.
"El Niño has an inclination to hinder tropical activity during the summer months in the Atlantic Ocean. The effects of El Niño for the east coast are much more variable and are strongly dependent on the strength of the episode."
Forecast models are indicating that El Niño will develop later this year, but there is significant uncertainty as to whether that develops through the summer or fall months.
Currently, NOAA’s Climate Prediction Center says there is a 50% chance of El Niño developing during the summer or fall.
"El Niño is notoriously difficult to forecast during the spring months," Vettese says.
"There have not yet been any studies that have successfully concluded why spring forecasts for El Niño don’t verify well but it is noted in the data that spring forecasts for El Niño are especially challenging."
Meanwhile, Weather Network forecasters are predicting a slow start to spring with consistently warm weather still a few weeks away for some communities.
Find out what spring will look like in your region with our 2014 Spring Outlook.