How The -PDO Dominated The Pattern In A Rare Way Through Mid-January

[bluewave]

http://www.climatecentral.org/news/disappearing-el-nino-throws-a-wrench-in-noaas-winter-outlook-15134

 

 

“This year’s winter outlook has proven to be quite challenging largely due to an indecisive El Niño,” Halpert said. The demise of El Niño stands out when looking at the historical record that stretches back 60 years. During that time there has never been a similar case in which water temperatures warmed so much during August, and yet El Niño conditions failed to take hold, Halpert said.

“When we reach a certain threshold by August, in September we have always proceeded right into El Niño,” he said.

 

 

 

 

The interesting thing about the El Nino peaking early was that it occurred with a -PDO profile 

that we have more commonly seen proceed a La Nina winter rather than an El Nino one.

The last time we saw this low a late summer PDO index was 1955.

 

 

 

The impact of the brief warming in the Tropical Pacific was to give us a more El Nino looking

pattern in October. The fading Nino Pattern kept the EPO from going really positive like

we normally see in a -PDO October. October looked more like one that would lead into

an El Nino winter.

 

-PDO October Composite

 

 

October 2012  -EPO dominated

 

 

 

By December we were experiencing the typical -PDO pattern with a -PNA in place.

 

DJF -PDO composite

 

 

December 2012

 

 

 

The amount of warmth that the Eastern US experienced with the AO index in December 

averaging below -1.500 was also very rare. Typically we see a colder temperature

profile associated with such a low -AO in December.

 

-1.500 December AO Composite

 

 

December 2012

 

 

We can also see the influence of the pattern resembling something more like a -PDO

this month with the relatively short rise of the PNA into positive territory before declining

again.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[bkviking]

Bluewave, excellent post. Other than the incipient El Niño collapsing to neutral over the past autumn, was not 2010-11 a -PDO year, with a La Niña? I don't remember the -PNA figures but is it safe to assume it was unfavorable? We all know the -AO/-NAO regime was dominant that year, and it seemed to dominate the pattern. And looking at the composite years you showed just based on the AO alone, it looked like a reasonable call from most people for a cold, snowy winter this year--though not ideal with an imperfect Pacific unlike 2009-10. And based on the composite index you showed would lead a betting man to just await Eurasian Snowcover results per Judah Cohen in October and make your bets then because you'll win far more often than you lose. We certqinly have had our -AO this year, more often than not with a -NAO. Either way, a long stretch of winter awaits.

[bluewave]

Bluewave, excellent post. Other than the incipient El Niño collapsing to neutral over the past autumn, was not 2010-11 a -PDO year, with a La Niña? I don't remember the -PNA figures but is it safe to assume it was unfavorable? We all know the -AO/-NAO regime was dominant that year, and it seemed to dominate the pattern. And looking at the composite years you showed just based on the AO alone, it looked like a reasonable call from most people for a cold, snowy winter this year--though not ideal with an imperfect Pacific unlike 2009-10. And based on the composite index you showed would lead a betting man to just await Eurasian Snowcover results per Judah Cohen in October and make your bets then because you'll win far more often than you lose. We certqinly have had our -AO this year, more often than not with a -NAO. Either way, a long stretch of winter awaits.

 

Thanks. Even though we had a weak La Nina last winter, it wasn't so much the PNA that was the problem.

We got stuck with the +EPO +AO +NAO pattern with the warmth dominating North America.

 

We probably would have had a snowier and colder December if the El Nino was able to develop

in concert with the strong -AO. My guess is that the PNA would have been more positive suppressing

the SE Ridge like 2002 and 2009.