Models and experts lean toward strong El Niño forecast for the fall

Jason Samenow, THE WASHINGTON POST

El Nino is here, strengthening, and the buzz is growing that it could become a “big one” by the fall or winter. The global consequences of a powerhouse El Nino would be enormous. But just how likely is that? Both computer model and human forecasters suggest it’s a very real possibility, at least a 50-50 one. Computer models are particularly aggressive in their forecasts.

Five ways a strong El Nino could affect our weather

Average of dynamic computer models (yellow curve) forecast a strong El Nino event by the fall. (International Research Institute for Climate and Society, adapted by CWG)
Average of dynamic computer models (yellow curve) forecast a strong El Nino event by the fall. (International Research Institute for Climate and Society, adapted by CWG)

The models forecasts compiled by the International Research Institute (IRI) for Climate and Society, based at Columbia University, on average predict a strong event by the fall.

The Australia Bureau of Meteorology (BOM) notes its computer model forecasts, on average, call for a very strong event.

Very strong or “super El Nino” events fall at the most intense end of the El Nino spectrum, which starts at weak and then steps up through moderate and strong levels.  Only two events in modern records have ever achieved “very strong” intensity were the events in 1982-1983 and 1997-1998, which was the strongest on record. The 1997-1998 event is well-known for contributing to torrents of rain in California, leading to $550 million in damages.

(Note that El Nino events earn their strength designations according to how much warmer than normal ocean temperatures are in a section of the east central tropical Pacific, known as Nino region 3.4. A weak event has ocean temperatures 0.5-0.9 C warmer than average, a moderate event 1.0-1.4 C warmer than average, a strong event 1.5-1.9 C warmer than average and very strong more than 2 C above average.)

Some forecasters view the models with skepticism. Last year at this time, many models were predicting a weak to moderate El Nino event for the fall which failed to materialize.

But others feel the models are onto something, pointing out that this year, unlike last year, El Nino is already firmly established and on the cusp of moderate strength.

Read more at: Models and experts lean toward strong El Nino forecast for the fall – The Washington Post