Friday, June 28, 2013

Negative PDO Looking More Likely This Winter

The Negative phase of the Pacific Decadal Oscillation (PDO) appears likely as we head into this winter.

Shown above is an average of multiple globally-produced forecast models, showing sea surface temperature anomalies for November-December-January of 2013-2014. The circled area shows the trademark presence of the negative PDO- we see a body of above normal sea surface temperatures in the northeast Pacific, surrounded by below normal sea surface temperatures in the waters immediately offshore the coasts of western Canada and southern Alaska. While this covers two of the three big winter months, the PDO is called the Pacific Decadal Oscillation for a reason. We have been in the negative phase of the PDO for a while, and even without looking at this model suite, there is a decent probability that we will be in a negative PDO this winter.

In the temperature department, the negative PDO results in above normal temperatures for much of the nation. The core of the heat tends to be centered in the Southern Plains, but the Eastern Seaboard, Northeast, Midwest and Plains get in on above normal temperatures when the negative PDO arrives. It is important to note that the Pacific Decadal Oscillation is not the sole driver of weather; many other variables go into the equation of a seasonal temperature and precipitation pattern.

For precipitation, the negative PDO brings about a decidedly below normal trend in the Gulf Coast region and into the Southeast. While the severe drought observed just a year or two ago in the southern Plains has been alleviated to some point, it would only take one more winter of below normal precipitation to bring back some effects of that drought. Again, I cannot emphasize enough the fact that the PDO does not decide the entire seasonal trend- many other large and smaller-scale variables go into a seasonal weather pattern.



Anonymous said...

I do not agree with this forecast at all. How can you say negative PDO with all of the different models indicating a positive PDO.

Andrew said...

All six of the NMME models show a negative PDO. If you believe a positive PDO is represented by a body of warm water in the northeast Pacific, you are mistaken for the negative PDO.

GuruOfReason said...

I love how 1977-1978 is one of the analog years in the study. I would love to experience such a winter.

I.want.snow. . . . said...

I. Want. Snow. . . .

Anonymous said...

Hai Andrew I'm new to your blog and I really like it! There is an issue though with it because when I try to comment nothing appears afterwards. Why is this happening? Thanks and keep up the good work :)

Andrew said...

Anonymous: The comments get through, but needed to be moderated by me before they are published due to previous issues with spamming.

Eric (weather advance) said...

Andrew I posted this on another forum & on weather advance I thought you would like to read it "Remembering the East Coast Nightmare of 1893″
The 1893 hurricane season, although I know 1954 & 1955 are bad with Carol, Edna, Hazel, Connie, & Diane, 1893 absolutely blows away those years, and it’s the US East Coast’s worst nightmare. With the 1893 NY hurricane “the midnight storm” directly hitting NYC in August (one of only 2 hurricanes, the other one being the Norfolk Hurricane of 1821, to pass directly over New York City.) & it is this hurricane that destroyed the resort island off Long Island called Hog Island, ( in fact we’re still finding debris from this storm). As the New York Times puts it this storm was “a mighty war of winds and a great tumbling of chimneys”. The storm was truly devastating, brought a 30-foot storm surge, in fact it was so bad that bird’s nests that were destroyed by the storm, came raining down in the thousands in central Park following this storm.

Eric (weather advance) said...

"1893 is one of only 2 seasons, the other being 1998, to have 4 hurricanes in the Atlantic Ocean at once!! (could only imagine AGWers hysteria, lol). We were actually lucky that season that they didn’t see a 4th hurricane hit the US eastern seaboard, luckily a last minute trough stopped the San Roque hurricane from hitting the coast. In fact, speaking of storm tracks, I noticed something quite disturbing between this year & 1893, in looking at the tracks of the season’s first two named storms, I was astonished to see that they seemed to closely resemble that of Tropical Storm Andrea & Barry.
Hurricane One (1893)
Andrea (2013)
Hurricane Two (1893)
Barry (2013)
Now, when I see the track Hurricane Three (1893)
a few things stick out at me, first of all, if you look at the Berthas of 1996 & 2008 (the MJO analogs, where the behavior of the MJO in those years seems very reminiscent of this year in that there is very constant bombardment into the Indian Ocean phases 2 & 3, very little movement elsewhere, especially in the western Pacific.) this storm system seems to go right up the middle of their tracks, interesting.
1996 Bertha (link)
2008 Bertha (link)
Actually, what is kind of scary is just how close Hurricane Three (1893) looks to 1996′s Hortense
1996 Hortense-
Hurricane Three-(1893)

Eric (weather advance) said...

Also, I like how this storm system (Hurricane Three (1893)) follows down the general ideas I currently have in terms of track for this upcoming Cape Verde Storm, I think somewhere in between Claudette of 1979 & Anna in 1969 will give us a good idea on where this system may go (also remember both of those years are also hurricane analogs that I had out in my hurricane forecast back in March that included years like 1960, 1969, 1979, 2004, 2010 (1996 was recently added). Thus, let’s seriously hope these similarities to 1893 end in a hurry, because if they don’t, wow this could be an unimaginable year for the US east coast, but 1893 also I like for how it forced 2 hurricane strikes into the central Gulf, which goes along with the ideas that East Coast & the Gulf need to watch out this year.
Also, 1893 was a sunspot extremity year falling at the peak of solar cycle 13, and if you recall back to some of my previous comments, I have mentioned how low & high sunspot years are particularly dangerous for the US coastline. (link) . Now, also remember the worst of the 1893 hurricane season came roaring in around mid August when a parade of storms smashed the US eastern seaboard until October, if this any indication what this year is like & knowing climatology, I would definitely say that what we are going to observe in July with a cyclone potentially getting unusually close to the US coast (at least that’s my thoughts for now) this will only be a “taste” of what the hurricane season has to offer come Aug & Sep.

Andrew said...

Very intriguing data, Eric, splendid as always. While the next chance for tropical development does not appear to be in the offing in the short term, I fear for late July, August and much of September.

Eric (weather advance) said...

@ Andrew
Thanks & I thought you would get a little entertainment out of this, I have a new weather site that was created thank mainly to Mark from US weather plus (that kid really has a lot of potential I'm telling you, for as young as he is, I remember when I was that age I was completely glued on the Weather Channel, lol) where I make local forecasts for the Carolinas (my posts are thankfully shorter & less boring or at least, I'll try to keep them that way :) ).