NOAA Issues La Niña Watch For Winter 2017 - 2018

NOAA has just issued a La Niña Watch for the fall and winter of 2017 – 2018. The NOAA report puts the chances of a La Niña event in 2017 – 2018 at 55-60%.

La Niña events can drastically affect the seasonal snowfall for ski resorts across North America by shifting the jet stream northward, making for a colder and more precipitous winter for the majority of the northern Rockies and PNW.

“In short, forecasters think that the sea surface in the Niño3.4 region will continue to cool, and the atmosphere will respond with a strengthened Walker circulation—the characteristics of La Niña. While chances of La Niña do have the edge in the current forecast, the odds only top out at about 60% likelihood that La Niña conditions will prevail in the winter. Climate forecasters will take this into consideration when developing the forecast for this coming winter, which will be released in October.” – ENSO Blogger, Emily Becker

Climatologists began noticing a change in ENSO conditions this August when equatorial subsurface sea temperatures in the Pacific began to dip below their average, signaling a possible shift to La Niña conditions by the fall.

Average sea surface temperature (SST) during August 2017, shown as departure from the long-term (1981-2010) average. Red shading shows where SSTs were above average and blue shading shows where they were below average. Climate.gov figure from CPC data.

*A La Niña watch is issued when conditions are favorable for the development of La Niña conditions within the next six months.

Official La Niña Watch From NOAA:

The September ENSO forecast is out!! Forecasters think there is an approximately 55-60% chance of La Niña this fall and winter, so we’re hoisting a La Niña Watch. Read on to find out what’s behind this development!

The ensemble of models from the North American Multi-Model Ensemble (NMME) is predicting that La Niña will develop this fall, and last just through the winter.

The chances of having “Back-to-back” La Niña’s is also not impossible, having happened 5 different times between now and 1950.and have occurred at least five times since 1950. The most recent La Nina event (*2010-2011) resulted in one of the Western United State’s most epic ski seasons ever followed by a weaker event in 2011-2012.