Weak El Niño conditions

Pacific Meteorology Climate Services Help Desk
1

Hi all,

Over the last month, we saw NOAA go out and acknowledge the arrival of El Niño conditions, citing warmer than average sea surface temperatures, warm sub-surface waters, and a westerly wind burst.

These patterns have culminated in increased rainfall and convection in the vicinity of the International Dateline. The Niño 4 Index has exhibited the warmest sea surface temperatures (and anomalies) over the past several months, priming the surrounding regions for enhanced rains and pushing the odds for the MJO to stand in the region. This, overall, signals some ocean-atmosphere coupling.

The “flavour” of the El Niño is much closer to the Modoki (central-based) style than the canonical one.

Over the next few weeks to months, this is forecast to continue. Some dynamical models suggest that the event may transition to a classical event as we head through 2019.

This may contribute to a longer-lasting tropical cyclone season in the Southwest Pacific.

rcc
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Precipitation anomalies over the last month; note enhanced rainfall around the International Dateline

2

Hi Ben,

I agree with you on your current climate summary and how the SOI behave in the last few weeks also makes me think. My only question is what are the models forecasting skills at this time of the year. If this weak El Nino is to establish in the Pacific then we are looking into similar pattern to 2014/15 -16.

3

Hi Philip,

The models do have a tougher time forecasting ENSO this time of the year due to the so called “Spring Predictability Barrier.”

However, I do think that with persistent weaker than normal trade winds in the western and central Pacific, the barrier might play less of a role this year.

My current analog package includes 2015, 2004, 2003, 2002, 1997, 1993, and 1991. It will require some fine tuning as the strength of the El Niño event becomes clearer.

Have a good day.

Ben