Saturday, May 02, 2009

Developing El Nino?

Signs are pointing to the development of an El Nino for later this year. Don't get excited in thinking that all Ninos = snow as they don't. El Nino events impact our region in many different ways -- from the snowy winter of 2002-2003 to the sleety winter of 2006-2007 to the "tropical" like "winter" of 1997-1998 (the Super Nino, if you will). Regardless of the overall snow impact, Nino winters tend to be stormier than not. Needless to say, talking about the specific weather that will happen in 7-10 months from now is quite speculative in nature but the events that are happening now can be harbingers of what is to come.

Click on the graphic below to see the animation of subsurface oceanic temperatures in the tropical Pacific. The oranges and reds that develop and grow in coverage on the graphic signify warming that is taking place below the ocean surface. These warmer waters could eventually work their way to the surface and develop the El Nino event, assuming that past performance and forecasts are correct.

The model forecasts for ENSO (which is the acronym that El Nino is a part of) for the coming ten months show the consensus that a Nino will develop. While not every model agrees, the majority do and that's a telling sign that can be backed up the oceanic temperature analysis provided above.

How strong of a Nino? It's far too early to say. There are a few models that are very aggressive and want to take the Nino to a strong level (stronger than our last nino event in 2007) while a good chunk of the models take the Nino to a less aggressive state, somewhere comparable to 1992-1993 or perhaps more along the lines of 2003.

Yes, there are other factors that will go into making the upcoming winter rock...or blow chunks. North Pacific ocean temperatures, the NAO, solar activity, and the Atlantic oceanic temperature profile all matter as well. Those things can be sorted out over time. With that said, the development of a Nino for this winter may be a sign of a stormier ride compared to the past few.