The end of a two year period of El Niño was in sight after the mild winter of 15/16. La Niña was on its way. El Niño and La Niña are important weather phenomena that express a decisive influence on the weather in some parts of the world and in such a way that it can be the difference between an epic winter and a bad winter. The temperature is around 0.1 to 0.3 degrees lower during a La Niña year. That doesn’t seem much, but it can be the difference between rain or snow on the lower parts of the mountain.
During El Niño, a deep pool of warm water usually restricted to the western tropical Pacific is replaced by a much larger, more shallow pool of warm water that covers most or all of the tropical Pacific. The expanded zone of warm sea surface temperatures allows more heat to be conveyed from the ocean into the atmosphere for months at a time. As a result, globally averaged temperatures often rise by a few tenths of a degree Fahrenheit during the latter stages of a strong El Niño event. Conversely, global temperatures can drop by a similar amount during a La Niña event. (source)
TIP: Read more about La Niña and El Niño and the consequences for our daily weather here
When a La Niña period was announced this spring, lots of resorts were pretty happy. But NOAA wasn’t too optimistic about a La Niña anymore in September. The Japanese JMA however kept believing in a La Niña and early October both weather services agree. There’s a reasonable chance that we’ll deal with a La Niña this falll and winter. NOAA estimates the probability around 70%, while JMA is a bit more pessimistic with 60%. This means that El Niño is definitely history. This means that the chances for lots of snowfall in North America just got bigger.
TIP: Why will La Niña bring plenty of snow to North America?
La Niña will bring plenty of snow to North America and is also held responsible for the hurricane season on the Atlantic Ocean. Already 15 storms have been counted and the season runs until November 30th. But there are more areas in the world where La Niña will influence the weather.
And for Europe?
There’s no proven correlation between the temperature and precipitation for Europe. In a previous article, I looked to data more closely and I checked what the influence was of La Niña on the snowfall in the Alps. The conclusion was: there’s no influence. The North Atlantic Oscillation (NOA) is a more important parameter for the Alps. At the moment it’s negative. If this trend continues then chances on a nice winter are realistic.
TIP: Read more about the NAO as winter forecaster.
I’ll check some more parameters the next couple of weeks. I’m getting more and more positive about this winter!