El Nino Developing in Tropical Pacific; Likely For Next Winter

July 2, 2012

I mentioned this back in April or May, but now the signs are definitely here…The warm phase of the El Nino/Southern Oscillation (ENSO) appears to be setting up for the upcoming seasons.  NOAA officially has had an “El Nino Watch”  up for over a month, but since that time the tropical Pacific has continued to warm.   This is an animation of sea surface ANOMALY (temperature deviation from normal), showing the spreading “tongue” of warmer than normal water over the past two months.  It’s now stretched halfway across the Pacific Ocean.  You can only see the animation if you click on it:

Remember that we’ve seen two years of La Nina (cool phase) conditions too.

As I mentioned in an earlier post, I’ve seen research and heard talks mentioning that forecasting the emergence/continuation of ENSO patterns is worst from March-May, then forecast confidence increases rapidly as we move into midsummer.  In the case of this year, the long-range climate models have been pointing to either neutral (La Nada) or El Nino conditions developing across the Pacific this summer.  The latest run of the CFS (Climate Forecast System) model shows a strong El Nino developing by this upcoming Fall.  El Nino conditions are +0.5 or higher on the chart.  La Nina -0.5 or lower:

Here is a “plume” of many different models:

The message appears to be the same: La Nina isn’t coming back, we MIGHT have a La Nada winter, but far more likely is an El Nino Winter 2012-2013.  The last two events were winters 2006-2007 & 2009-2010.  The 2nd was a classic one here with long periods of slow weather after a big start in November.  Snow didn’t even fall below 3,000′ during all of January and February!  BUT, it started out with lots of stormy weather in November, a big freeze in early December, and all of 2.5″ of snow in one night in late December.  The winter of 2006-2007 (the El Nino before that) was almost exactly the same in November…crazy busy with lots of storms.  We even had our best windstorm in 10 years in December that year.  But, like most El Ninos, the 2nd half of winter was just dead; although we had a mini-cold spell in January and a surprise snow while I was in San Antonio at a weather conference.  February was mild and drier than normal, typical for El Nino winters.

By the way, these graphs, chart, and info come out every Monday at this address:  http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

Chief Meteorologist Mark Nelsen