You will be hearing quite a bit about El Niño in the coming weeks and months as it is on the verge of forming. So, what is El Niño?
The definition of the event and its naming below are from Wikipedia.
El Niño is the warm phase of the El Niño southern oscillation (commonly called ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (between approximately the international date line and 120°W), including off the Pacific coast of South America.
Here is how it was named.
Developing countries dependent upon agriculture and fishing, particularly those bordering the Pacific Ocean, are the most affected. In Spanish the capitalized term "El Niño" refers to the Christ child Jesus (literal translation "The (male) Child"). La Niña, chosen as the 'opposite' of El Niño, literally means "The (female) Child). El Niño was so named because periodic warming in the Pacific near South America is often noticed around Christmas.
NOAA splits the equatorial Pacific into four regions where they monitor sea surface temperatures (SST). They take the readings each week and calculate the departure from normal water temperature. They use one of the El Nino regions (3.4) to determine whether an El Nino is forming. If the departure average is +0.5 degrees Celsius for three consecutive months then it is considered an El Niño.
See a pair of animated maps from the Climate Prediction Center
Actually, it takes three consecutive three month running averages. So, June-July-August (JJA) the reading was 0.0 degrees, right at normal. Then July-August-September (JAS) the reading was 0.0. During the last month the SST anomalies have crept up to 0.2 degrees, 0.4 degrees and the latest weekly reading was 0.6 degrees. So, we are heading towards an El Nino and we will be talking about this all winter.
What does this mean?
Usually, El Niño winters are not cold with the warmest anomalies found in the northern USA. The southern USA is usually wetter than average and colder than average. California usually gets wet. Kansas City is in between and can have all sorts of possibilities, but the weather pattern leans wetter than average for KC.
However, this is not always the case as there are many other factors:
- How is the weather pattern setting up?
- Where do storm systems want to reach their peak strength for the season?
- Where do the storm systems want to avoid?
This is the LRC (Lezak's Recurring Cycle) that we use here at 41 Action News to make the winter forecast. We will be taking this into account, and the fact that El Niño is forming to formulate our winter forecast. It will be aired on December 4 when we have our winter weather special.
