Odds Increasing for Predominantly Positive NAO

[donsutherland1]

After examining Atlantic Ocean SSTAs, summer snowcover, and 500 mb height anomalies, it appears that while there will be episodes of blocking this coming winter, the NAO will be predominantly positive. In other words, episodes of reduced blocking will be more commonplace than those with significant blocking. I do expect a few episodes of blocking, though more frequent periods where blocking is reduced if the trends hold up.

Although it may be controversial to tie summer snowcover to the NAO, research by Dr. Mark Saunders, Budong Qian, and Benjamin Lloyd-Huges of the Benfield Hazard Reserach Centre, Department of Space and Climate Physics, at University College London has supported such a proposition. Indeed, they conclude, "We find that summer snow cover over northern North America and northern Eurasia is linked significantly to the coming winter NAO state."

Needless to say, I place greater emphasis on the SSTAs.

In addition, it appears that the tendency for blocking can begin showing up by September and usually no later than November in the 500 mb height anomalies. Typically, one finds an above normal height anomaly (approximately around the Eastern Canada-Greenland-Iceland region) surrounded by below normal anomalies ahead of winters in which there is significant blocking. Conversely, one finds a below normal height anomaly surrounded by above normal ones prior to winters with reduced blocking.

At this time, September 2003 seems to be shifting toward the signal that favors reduced blocking.

<img src="http://www5.wright-weather.com/bb/attachment.php?s=&postid=115559">

Following the end of September, the first few days of October also seemed to suggest a trend toward reduced blocking.

<img src="http://www5.wright-weather.com/bb/attachment.php?s=&postid=116087">

Nevertheless, these are early indications. Usually by mid-November, it is far more apparent as to whether the winter will see a primarily negative or positive NAO.

[Guest]

And just to remind a few as well this in no way means that winter is done with.................For instance the winter of 1993/94 had this same set up (+NAO) and well most know what came of that winter especially those from the Midwest to the Mid-Atlantic and NE! More or less it was a extremely cold and icy winter! My town i live at now for example had the coldest temp ever recorded for the state of Ohio which was a bone chilling -31!!!!!!!

Anyways thanks again Don for the great and informative post!

[JCT777]

Thanks for the info, Don. As long as this winter is not a repeat of 2001-2002, the NAO can do whatever it wants.

[GAStorm]

Don and KOW,

Do you think the Pacific storms will be a factor this winter? Unfortunately, the cold air usually is held up in Canada when those storms come ashore. Not sure if that would hold back arctic air this year since it seems the patterns could rapidly change.

[donsutherland1]

GAStorm,

I'm finalizing my analogs at this time. Briefly, I believe that there will be a fair share of Pacific storms with California (especially southern California) seeing above normal precipitation during the winter. I'll have more on the winter in the next day or two.

[donsutherland1]

John,

I do not expect the coming winter to be as warm or relatively snowless as Winter 2001-02. My initial ideas concerning snowfall still look good after taking into consideration developments since I posted those earlier amounts.

[wx247]

Doesn't a lot of southern California storms in the winter favor and El Nino pattern?

[GAStorm]

Thanks Don! Looks like it could be real interesting for southern storms this winter. Hopefully the cold air will be there!

[roarusdogus]

FWIW, some very nice blocking is going to be developing in the coming days. The classic look of blocking is occuring if you look at the Candian Ensemble forecast. Above average temps in the Canadian Arctic, with the cold stuff forecasted pointed toward the eastern U.S. So, a strongly Neg NAO is definitely the short term and medium range problem, as this blocking will cause havoc among models and forecasters until they get a handle on it. This strong blocking may act to keep troughiness in the east into next week. Could this mean a prolonged period of below average temps? It's possible, especially in Maine IMO. Maine may really be in for a cold lovers treat. I'll be watching the Euro tonight to see if it still has the "heat" in parts of the midwest. With 850 temps rising to the high teens later this week(according to the Euro)in the plains, this would spell some genuine October style heat.

[roarusdogus]

Doesn't a lot of southern California storms in the winter favor and El Nino pattern?

They are more numerous during an El Nino but can definitely still happen without one. The ol pineapple express always make me shudder. It can bring lots of mild pacific air into the country. One of the reasons why El Nino winters are always so darn mild.

[roarusdogus]

John,

I do not expect the coming winter to be as warm or relatively snowless as Winter 2001-02. My initial ideas concerning snowfall still look good after taking into consideration developments since I posted those earlier amounts.

I'd be worried if we had another season like that of 01-02. It ended brutally cold around here and stayed very cold through the beginning of June but the winter itself was incredible. It was colder on a couple of days here in early June than what it was one day in January. How about that?

[donsutherland1]

Wx247,

Here are two illustrations of El Nino's impact on precipitation:

<img src="http://www.cpc.ncep.noaa.gov/products/predictions/threats2/enso/elnino/USprank/djfm.gif">

<img src="http://www.cpc.ncep.noaa.gov/products/predictions/threats2/enso/elnino/jfmpstat/ca0.gif">

At this time, there are growing indications (modeling) which are supported to some extent by analogs that the Neutral ENSO could give way to a weak El Nino at some point this winter, particularly as the winter progresses.

[rob22]

And just to remind a few as well this in no way means that winter is done with.................For instance the winter of 1993/94 had this same set up (+NAO) and well most know what came of that winter especially those from the Midwest to the Mid-Atlantic and NE! More or less it was a extremely cold and icy winter! My town i live at now for example had the coldest temp ever recorded for the state of Ohio which was a bone chilling -31!!!!!!!

Anyways thanks again Don for the great and informative post!

actually for people to the east, 93-94 only had 1 good month. dec and feb were not very cold at all. you cant have a good winter with a dominating pos nao.(check out 94-95) You need the neg nao to drive down cold temps. once they are in place, you can have events with a pos nao but they arent usually that strong. even pres day wasnt strong with the storm itself. for more examples of pos nao dominated winters, just check out 2001-2002 and 99-2000 with the exception of the 2nd half of jan.

[Guest]

Well guys i may have a little suprise for all..................BTW i did take this into account as well when i did my winter outlook!
Graphics spell it out loud and clear!!!!! This is something very few can argue IMO...................Oh and as well trust me when i say that this is NOT about global warming!!!!!!!!

http://www.intellicast.com/DrDewpoint/L ... rticle.pdf[/url]

And after you read that this little link below shows the trend as well!!!!!!!!!
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/JFM_season_nao_index.html

Only thing that can possibly screw up the winter for areas east of the rockies especially maybe would be a strong ENSO like we had in 97/98! Which i nor most any others dont see happening!!!
I have this slight feeling that someone by the name of HM has probably seen that top link??????

Anyways i would like some feedback from Don on this as well as others who are familure with all this!!!!!!!This may as well argue your POS NAO as well Don besides what may be taking place in the short term.........

[JCT777]

actually for people to the east, 93-94 only had 1 good month. dec and feb were not very cold at all.

You may be right about December, but I specifically recall February being quite chilly - and having several ice/snow storms in my area. I do not know what the Feb temp was in 1994 in relation to average, but I would guess it was at least slightly below normal where I live. And January had some extremely cold temps. I recall one morning with a low temp of -14 F and a high temp of 2 F. Coldest day I can recall in the past 25 years.

[roarusdogus]

Well guys i may have a little suprise for all..................BTW i did take this into account as well when i did my winter outlook!
Graphics spell it out loud and clear!!!!! This is something very few can argue IMO...................Oh and as well trust me when i say that this is NOT about global warming!!!!!!!!

http://www.intellicast.com/DrDewpoint/L ... rticle.pdf[/url]

And after you read that this little link below shows the trend as well!!!!!!!!!
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/JFM_season_nao_index.html

Only thing that can possibly screw up the winter for areas east of the rockies especially maybe would be a strong ENSO like we had in 97/98! Which i nor most any others dont see happening!!!
I have this slight feeling that someone by the name of HM has probably seen that top link??????

Anyways i would like some feedback from Don on this as well as others who are familure with all this!!!!!!!This may as well argue your POS NAO as well Don besides what may be taking place in the short term.........

There's no doubt the trend is toward more episodes of Neg Nao. This correlates very well with studies of the PDO. We are currently in the cold phase of the PDO, which started in the late '90s. During these cold phases, we see much more in the way of Neg NAO values. The last cold Phase ended in the '70 and volia!! The NAO started trending upward from there, just as it started trending downward since the cold phase started again in the late '90s. To me, this says a lot as to why the '80s and especially '90s were warmer than that of the previous couple of decades. Also, the '30s were very much similiar to that of the '90s as far as warmth goes. As a matter of fact, a lot of the summer records come form the '30s, a very warm decade for sure. During cold phases of the PDO, you generally see warmer waters in the Atlantic, right where you need them for a Neg NAO value. This can also be correlated with more hurricane activity as we saw in the '60s and we seem to be seeing again. Climate really is a big cycle, which is one of the reasons why I'm very skeptical of anyone trying to claim the '90s were warm due to human induced global warming. I can very clearly see by looking at history that there is a very clear ocean cycle to explain warmer and colder decades.
Now, this being said, this is NO WAY these links prove Don to be Wrong. You can have winters with a predominately pos NAO even when the average for a year or years is neg. So, these links that KOW showed by no means proves Don wrong. If you decided to forecast the NAO just by odds alone and no science involved, you bet you would forecast it to be mainly neg this winter. IMO, the water temps in the Atlantic, what we have seen the last year and odds are pointing toward more neg values than pos this winter. My guess is that when averaged out after winter, the average will come out neg. but this is just simply my opinion.

[roarusdogus]

actually for people to the east, 93-94 only had 1 good month. dec and feb were not very cold at all.

You may be right about December, but I specifically recall February being quite chilly - and having several ice/snow storms in my area. I do not know what the Feb temp was in 1994 in relation to average, but I would guess it was at least slightly below normal where I live. And January had some extremely cold temps. I recall one morning with a low temp of -14 F and a high temp of 2 F. Coldest day I can recall in the past 25 years.

Jan of 1994 was the first time and last time in my memory that public schools around the state were closed because it was too cold outside. Too cold?? Yes and I'm in Michigan. Our coldest morning here was -22. This is warm compared to some of the temps away from the lakes. Last March, we came close to this one morning as we got down to -18. That was very impressive considering it was March. The difference though was in Jan of '94 that -22 came with a howling wind. The windchill on the old chart was in the -60s!! BRRR

[JCT777]

Roar - we had the same situation for several days in Jan 1994. Most schools in the area were closed because of the cold. We even had a day or two where they were having mandatory power outages for 1 to 2 hours at a time because of the demand on electricity. I still drive the same car that I had during that winter, and that -14 F day is the only morning I recall having trouble starting the car (other than the two times the battery died).

[donsutherland1]

King of Weather,

I've seen both the report and the long-run NAO graph. There is little doubt that the NAO goes through periods where its long-run average can be positive or negative. Currently it's trending toward negative.

Neverthless, just because the moving average becomes negative does not mean that seasonal fluctuations to positive cannot occur. Indeed, during the 1869-70 to 1898-99 period where the NAO averaged negative, there were a number of winters with pronounced positive NAO indices.

Again, I have to caution that I do not see a raging positive NAO. In fact, I believe it would likely average weakly positive. This is a preliminary idea--and could be incorrect--and by mid to late November, it should become pretty apparent which signal may be "locking in" for the winter.

In spite of my expectation for the NAO, I still believe cities such as Philadelphia, NYC, Boston, etc. will see decent snowfall (just not as abundant as last winter) and the Great Lakes region should get into the act this winter, as I feel that there will be several episodes of significant blocking that will occur (possibly most pronounced in March if some of the analogs I'm examing bear out).

[Guest]

Well guys i may have a little suprise for all..................BTW i did take this into account as well when i did my winter outlook!
Graphics spell it out loud and clear!!!!! This is something very few can argue IMO...................Oh and as well trust me when i say that this is NOT about global warming!!!!!!!!

http://www.intellicast.com/DrDewpoint/L ... rticle.pdf[/url]

And after you read that this little link below shows the trend as well!!!!!!!!!
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/JFM_season_nao_index.html

Only thing that can possibly screw up the winter for areas east of the rockies especially maybe would be a strong ENSO like we had in 97/98! Which i nor most any others dont see happening!!!
I have this slight feeling that someone by the name of HM has probably seen that top link??????

Anyways i would like some feedback from Don on this as well as others who are familure with all this!!!!!!!This may as well argue your POS NAO as well Don besides what may be taking place in the short term.........

There's no doubt the trend is toward more episodes of Neg Nao. This correlates very well with studies of the PDO. We are currently in the cold phase of the PDO, which started in the late '90s. During these cold phases, we see much more in the way of Neg NAO values. The last cold Phase ended in the '70 and volia!! The NAO started trending upward from there, just as it started trending downward since the cold phase started again in the late '90s. To me, this says a lot as to why the '80s and especially '90s were warmer than that of the previous couple of decades. Also, the '30s were very much similiar to that of the '90s as far as warmth goes. As a matter of fact, a lot of the summer records come form the '30s, a very warm decade for sure. During cold phases of the PDO, you generally see warmer waters in the Atlantic, right where you need them for a Neg NAO value. This can also be correlated with more hurricane activity as we saw in the '60s and we seem to be seeing again. Climate really is a big cycle, which is one of the reasons why I'm very skeptical of anyone trying to claim the '90s were warm due to human induced global warming. I can very clearly see by looking at history that there is a very clear ocean cycle to explain warmer and colder decades.
Now, this being said, this is NO WAY these links prove Don to be Wrong. You can have winters with a predominately pos NAO even when the average for a year or years is neg. So, these links that KOW showed by no means proves Don wrong. If you decided to forecast the NAO just by odds alone and no science involved, you bet you would forecast it to be mainly neg this winter. IMO, the water temps in the Atlantic, what we have seen the last year and odds are pointing toward more neg values than pos this winter. My guess is that when averaged out after winter, the average will come out neg. but this is just simply my opinion.

Hello Roardog!!!! First off let me say that i am not sure of your intentions on this however its looking more and more like you have some sort of problem with me! Anyways those graphs dont lie...............How can anyone argue them? No i know it doesnt guarentee anything but they do show a Trend which is for colder and snowier winters for the USA as a whole...................Along with the other statements made about the NAO and stuff.............

And as far as what i said to DON???? PLEASE dont put words in my mouth!!!

This MAY as well argue your POS NAO as well Don besides what MAY be taking place in the short term.........

You SEE the word may.....................I hope this helps..

(Edited by me) Sorry if i came across harsh.................Just wondering why you said what you did here and in the other thread about the week ahead???