Thursday, April 26, 2012

Sure-Fire El Nino Next Winter? Not So Fast.

Many climate models are predicting an El Nino following the double dip La Nina this year and last year. While a neutral to weak El Nino (possibly moderate) is likely, the forecasts for a super El Nino will most likely not verify, and here's why.

Here is the past analysis for the Pacific Decadal Oscillation, or PDO. It is recognized by either a warm or cold temperature anomaly in the northern Pacific. Likewise, there are warm and cold phases, respectively. Right now, based on the above image, we are, and have been, in a cold phase. This means an increased likelihood for La Ninas. However, as observed in 2009, that is not always the case, hence the 'increased likelihood' part.

This is the PDO forecast out to 12 months off the ESRL's LIM long range model. As you can see above, we are projected to remain in a deep negative phase from now until at least March 2013. But let's not get ahead of ourselves. Long range forecasts can be ticking time bombs of failure, or fairly spot on. There is barely, if any, room for forecast success 12 months out.
I ran over some verification scores for 3, 6, 9, and 12 month forecasts off this LIM model. I got 81%, 67%, 55%, and 41% verification for those respective forecasting periods. Now, don't get me wrong here- 44% is a very high verification rate for a full year out. However, it does not ensure confidence.

All I am saying here is that those going for a super El Nino for the upcoming winter (I haven't heard any of those forecasts, but I'm bound to run across a couple sooner or later) should take a look at how strong the negative PDO will be and how it could very well tamper the possible El Nino down to a neutral or weak Nino year.



mike paulocsak said...

Hey Andrew.How's it going.I myself would like to see an la-nina winter.It's better for snow in the Ohio area.

ERN WX said...

A Nina doesn't look too likely, but there is still a SMALL chance of one happening. Me, I want a weak Nino. My area averages 6 inches above normal during weak Ninos, and just about every time we get an 8+ incher. But don't worry Mike, you will probably see at least one big one. For me, I think a weak Nino is favored. One thing that could help your area with snowfall would be Apps runners. Also the clippers will help. Noreasters are the best in my mind, but if I lived in your area, I would think differently. Take care. Gotta go. I'll try to be back.

ERN WX said...

Some things thta favor your area with above average snow. Low sunspot cycle= -NAO. Also active southern jet= more moisture & more storms. Volcanoes have been fairly active so they will cool temps a bit. Also last year, wasn't exactly great for anyone, so higher totals are likely. Mike, I think your area has a decent chance for an above average snowfall. Just remember, cold fall+ wet fall= cold winterand snowy winter. Just a few thoughts on winter. I really enjoy discussing weather with you, Mike. Have a great day!!!!!!!!!!