Odds Increasing for Predominantly Positive NAO

[Guest]

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).

Great reply as always....................Which i pretty much agree with those statements you have just made..................(See my snowfall forecast thread for what i think some of the NE cities and others will get this winter)

Either way i know as well that the NAO doesnt just stay fixed at one position or another.......................Btw seeing what you have just read.................You think maybe this has a bigger effect on the use of Analogs per say?????? Would love to hear your thoughts on that.......

[rob22]

feb 1994 averaged -1 degree below normal in pitt but that mostly came from the early part of the month and i was talking about e of the apps. middle-end feb 1994 was warmer and winter pretty much ended then too. but my point was, if there is a dominating pos nao, you will not like the results cold or snow wise.

[donsutherland1]

King of Weather,

I believe Dr. D'Aleo's paper provides a good climatology primer. Not only is it rich with charts and data, it discusses some of the most important factors shaping the climate.

I fully agree with Dr. Gray's hypothesis concerning the thermohaline cycle as explaining a relationship between the cooling of the Pacific and warming of the Atlantic that coincide. The changes occur over such a vast area and of such a magnitude that air temperature patterns cannot explain the changes. Hence, in my view, it is actually quite intuitive that ocean currents mainly explain the changes and that these changes are related.

With regard to the information in D'Aleo's paper, I use it as a larger backdrop against which analogs are reviewed (SSTAs, ENSO, QBO are very important factors for me). However, because the changes that occur are so gradual, I don't believe it materially affects analogs on a season-to-season basis.

Where I believe the paper is most valuable is explaining longer-term climate cycles of a decadal-type nature. Hence, for example, if one is looking to discuss the nature of winters for this decade, one can reasonably expect that they will be colder and snowier than those of the last decade given the factors D'Aleo cites. Not surprisingly, the 2000s have already seen NYC receive two seasonal 30" snowfalls, which matches that of all of the 1990s. The 1980s saw none.

[donsutherland1]

Rob,

The fierce cold in Winter 1993-94 made its mark on Pittsburgh, too.

Some records that were established:

All time lowest temperature: -22 on January 19

All time lowest mean temperature: -13 on January 19

Longest period with sub-zero readings: 52 hours (January 18 6 am. to January 20 10 am)

2 0f the coldest 19 days ever occurred in January 1994 (18th, 19th, and 21st)

In terms of monthly mean temperatures, the entire December-March period averaged below normal:

December 1993: -0.8
January 1994: -6.4
February 1994: -1.0
March 1994: -2.0

[roarusdogus]

Mr. King, calm down sir. I was merely stating some info on ocean cycles as well as pointing out that the graph you provided doesn't neccesarily prove Don wrong. I guarantee you would get somebody not real familiar with this stuff to look at that graph and think you were trying to prove Don wrong. So, I was merely explaining the situation, not anything against you personally, just trying to better explain the situtation in case anybody cares. I'm going to start calling you DT if you keep getting excited everytime someone makes a post contradicting yours.

[Guest]

Mr. King, calm down sir. I was merely stating some info on ocean cycles as well as pointing out that the graph you provided doesn't neccesarily prove Don wrong. I guarantee you would get somebody not real familiar with this stuff to look at that graph and think you were trying to prove Don wrong. So, I was merely explaining the situation, not anything against you personally, just trying to better explain the situtation in case anybody cares. I'm going to start calling you DT if you keep getting excited everytime someone makes a post contradicting yours.

LOL @ the DT comparison .............(Could take that as part compliment as well;) ).........................Anyways good point!
Something i really didnt think of when i posted that link..................I guess there is those who could easily end up doing what you said if they dont completly understand what that all means! Either way like Don said and that article it looks like we are in for a fun ride this decade unlike the last one!!!!!!!!!!!

[Stormsfury]

Nice convo here.

I'm not really sure what to expect this winter. So far this year, we've seen ...

Tropical Storm Ana in April - a record
512 tornadoes in the month of May - a record
Tropical Depression #2 in the far Eastern Atlantic in late June - another record for the furthest east depression for so early in the season.
Hurricane Isabel - hits Eastern NC and VA the hardest at least since 1933
Tropical Depression #19 - Possible furthest east TC this late in the season - (Still needs a lot of research through the records).

Not one thing really wants to fit any analog as of yet.

Anyways, I really like reading everyone's views on the upcoming winter. Some great reads. I haven't really formulated my own outlook for the winter, but it's highly unlikely that I'll do one since, well, LR isn't a strong point (unless it's a tropical weather outlook for the season).

SF

[JCT777]

feb 1994 averaged -1 degree below normal in pitt but that mostly came from the early part of the month and i was talking about e of the apps. middle-end feb 1994 was warmer and winter pretty much ended then too. but my point was, if there is a dominating pos nao, you will not like the results cold or snow wise.

In all likelihood, yes a dominating positive NAO would not be good for cold and snow. 1993-94 was an exception rather than the rule. I guess we shall see if a +NAO dominates this winter.