February PDO: +0.81

[donsutherland1]

In February, the PDO continued its strong rebound, rising to +0.81. In January, it was +0.44.

[Jrodd312]

What does that mean when the PDO goes positive?

[Stephanie]

I believe that a positive PDO with a negative NAO reflects a stormier period for the East, which it was.

[Guest]

So when is the PDO going to go negative... A negative PDO means lots of cold and snowy weather in the Pacific Northwest, especially if it comes with a negative PNA and AO... and even better, a La Nina.

[donsutherland1]

Brennan,

In my pattern discussion later today, I'll talk a little more about the PDO with respect both to hurricane season and also hints of what one might expect next winter with regard to the PDO or at least things to look for.

[donsutherland1]

You are correct, Stephanie. When the PDO is positive, the East tends to be colder and snowier. There is a fairly strong direct relationship between the PDO and PNA. In contrast, when the PDO is negative, the Pacific Northwest tends to be colder and snowier.

This winter, December was negative, January and February were positive. Snowfall for Philadelphia was as follows:

December 2004: 0.4"
January 2005: 15.6"
February 2005: 12.9"

[donsutherland1]

John,

I posted some specifics in my reply to Stephanie. A positive PDO, on average, favors the eastern United States with more cold and snow. A negative one favors the West.

The long-term PDO cycle is either transitioning to negative or is there. When that's the case, the PDO is more often negative than not. However, there's more to that than what might be implied. I'll cover that in a supplemental section to my weekly pattern discussion later today or tonight, as I don't have sufficient time to provide the detail right now.

[Stephanie]

Thanks Don! See that? I am learning a few thing!

[donsutherland1]

You're already very knowledgeable, Stephanie.

[Stephanie]

LOL! Thanks again Don!

[donsutherland1]

You're welcome, Stephanie. I'm just stating a fact.