OCTOBER PATTERN INDEX (OPI) MONITORING WINTER SEASON 2014-2015

[Ali1977]

-2.20 this morning, still very low but falling back a touch.

The PV in the 0330 is definitely looking more organised over Greenland, not sure if that effected the slight drop.

[chionomaniac]

-2.20 this morning, still very low but falling back a touch.

The PV in the 0330 is definitely looking more organised over Greenland, not sure if that effected the slight drop.

Do not be surprised to see the PV becoming far more organised during November. I think that a trough to the south of Greenland would be expected this year through the next month. Those expecting severe disruption of the PV during the next month may be quite disappointed.

[Penrith Snow]

Despite the new research I still can not imagine the UK getting a strong zonal winter following the very low OPI in October.

Yes, other factors will come into play but with an OPI below -1.5 the correlation is so strong.

We will never know until the time whether the weak Vortex brings a good Scandy Block or watch as cold heads into France but I really can not see the zonal washout of last year reappearing.

The Vortex will ramp up during November which will be very zonal but I would bet a 1000 pounds that the Vortex will be flopping about like a drunken sailor before Christmas.

I am keeping the faith and for those going back into the MetO LRF camp all I can say is Good Luck.

Andy

[The Post-modern Winter]

Splendid idea, you go do that quietly, while the rest of us do that boring science thing.

We promise to come and get you if anything "good" happens or if there is any "colouring in".

 

I'm entirely with NorthernRab here. Netweather, as a forum, but particularly with this thread, has an intellectual integrity that I think should be kept intact. I've been tempted to post at a number of points, but didn't want to interrupt the organic flow of the discussion. I think the work on the OPI is quite spectacular, but just as notable is the discussion within the thread form passionate and incredibly knowledgable people which I'm sure has impressed the research team working on this project.  

 

What this thread doesn't need is Terrier coming out from under his bridge, trolling the forum and ruining the intellectual and academic tone of the forum as mentioned above. All well and good doing so in the model thread where emotions run high, but this is different. Surprised the mods have let him get away with it really - A blot on what is a wonderful read. He really is the 'WORST POSTER EVER' . .

[Polar Maritime]

All well and good doing so in the model thread 

 

Trolling is not excepted anywhere are the Forum.

 

Can we please keep personal jibes "personal".

 

Thanks PM.

Edited October 28, 2014 by Polar Maritime

[johnholmes]

Having read through the last few pages including the Google translation of the post from the team investigating the possible links then maybe some should pay attention to this towards the end of their comments?

 

 It does not matter, because one thing must be clear: we're not ready to make predictions themselves, which is intended to predict something that has established a trust, otherwise it comes to guessing neither more nor less than to the alleged snowfall in Rome feared by some predictions agostani. What we will do is start a job verification and careful effort to correct any errors since the beginning of Decembe

 

They themselves are NOT making predictions, many on here are, and that is the problem. They need to do a lot more work as they suggest before they will feel confident in their theory. Okay it looks that the OPI has a link with cold and quite snowy winters in my area but there are exceptions. Until they finish their research, even if what some have shown possible for this upcoming winter, turn out correct, the theory has yet to be scientifically proven and peer tested.

It looks great but it needs time, something a number on here seem short of but to say 'back to square one' is unkind to say the least.

[sebastiaan1973]

Do not be surprised to see the PV becoming far more organised during November. I think that a trough to the south of Greenland would be expected this year through the next month. Those expecting severe disruption of the PV during the next month may be quite disappointed.

 

Well that's in line with Cohen's theory.

http://web.mit.edu/jlcohen/www/papers/Cohenetal_JC14.pdf

[chionomaniac]

Well that's in line with Cohen's theory.

http://web.mit.edu/jlcohen/www/papers/Cohenetal_JC14.pdf

Big time expecting exactly this Sebastiaan. Archangel centered high with Atlantic/ mid Pacific trough through November. If that doesn't occur then may go back to the drawing board for winter!

[Gael_Force]

Big time expecting exactly this Sebastiaan. Archangel centered high with Atlantic/ mid Pacific trough through November. If that doesn't occur then may go back to the drawing board for winter!

 

Would something along the lines of this late November forecast fit the bill?

 

[feb1991blizzard]

Would something along the lines of this late November forecast fit the bill?

 

 

 

Cracking blocking over the pole, I urge everyone on here to not be despondent, Nov will turn out zonal, as said earlier, its the bigger picture that counts, this is whats expected.

[SMU]

Nice post Croc........

[Crocodile23]

Without meaning to stir anything up, I find it surprising how astoundingly rude and dismissive people can be just because some one's work isn't giving them a cast-iron guarantee of a record breaking cold winter.

 

I don't think this is the main reason. Actually i'm not speaking specifically about any post here, but only speaking generally, but the main reason for mocking words about any such try like OPI for example, is that people don't understand how science works.

 OPI may be a complete bust(hopefully it isn't). But it opens new roads of research. And anyway it's a scientific try based on the scientific method that may or may not work after all, so it's a respectful one.

 

The problem is and always was that, ignorant about science people, ONLY SEE THE END RESULT. They could care less about the scientific in-between theory and research and the method and the probabilities and the margins of error etc of the method and they don't be amazed even for a second about the science any method has, they only see the white-black of the final result.

Edited October 28, 2014 by Crocodile23

[jonboy]

 

I don't think this is the main reason. Actually i'm not speaking specifically about any post here, but only speaking generally, but the main reason for mocking words about any such try like OPI for example, is that people don't understand how science works.

 OPI may be a complete bust(hopefully it isn't). But it opens new roads of research. And anyway it's a scientific try based on the scientific method that may or may not work after all, so it's a respectful one.

 

The problem is and always was that, ignorant about science people, ONLY SEE THE END RESULT. They could care less about the scientific in-between theory and research and the method and the probabilities and the margins of error etc of the method and they don't be amazed even for a second about the science any method has, they only see the white-black of the final result.

So true Croc to many people expect instant results and when they don't materalise as they expect the default is to rubbish whats been tried. I am sure this will see a lot of refinement over the coming years but its great that someone is trying something new and trying to expand our knowledge that ultimately could drive forward our ability to better forecast in the longer timeperiod than at present

PS loved your earlier post but way over my head but got the jist of what they are trying to do

 

[ukpaul]

There is a 'winter hopes' thread where anyone who disagrees with the figures that the OPI is coming up with can go and chunter instead (and a cracking post earlier by the way, which clarifies a number of issues for me). What annoys people is stupidity when they are busy wrestling with complexity. 

[Alexis]

People like to lump months together to create a season and give it a label. The weather can obviously change fortnight to fortnight, and even CET figures can be subject to extremes when a hot/cold spell straddles two months.

 

What I'm saying is that even the coldest winters will have mild, zonal spells, and mild ones can have severe cold spells.

 

A mild and zonal December can suddenly lead onto a bitter Jan and Feb. Or a mild January can be sandwiched between two extreme months.

 

If one calculation points to a mild, zonal signal and another points to a strong -ve NAO signal, are the two mutually exclusive? 

 

Not when you are looking at s time span of 3 months IMO.

[johnholmes]

One wonders how the OPI would have been in autumn 1946 or 1962 to name just two. Anyone able to provide that data please?

[Mucka]

I think we can put the negatives behind us and concentrate on the positives, such as croc's excellent post, no?

 

There have been wise words also about not judging the OPI validity against November patterns but I have a slight doubt about the consensus that seems to be forming that November will be zonal. There will be a fair bit of wind and rain around at first I'm sure as the PV begins to organise but I haven't seen anything in the MO that suggest a fast and flat pattern dominating the month with some quite strong Atlantic ridging and even mid latitude blocking being suggested a little more than one would expect in FI if there were no signal.

 

So I'm not making a forecast for second half of November, but I wondered, Is there a reason people are calling a zonal November that relates to the OPI or Strat thread or is it based on something else?

[Summer Sun]

-2.07 on the 06z

[Vorticity0123]

Let me try to explain the way OPI is calculated, in a rough approximated way of course, not revealing anything of the exact calculations of course, as the authors obviously want to keep it out of public until the paper get's peer reviewed and i respect that.

 

Lots of thanks a lot for this very elaborate and clear post! I am very grateful for the time you took to explain a rather complex variable. This is a great help to understand the concept of the OPI! 

 

It is also nice to see out of which elements the OPI is built upon (regardless of the exact positions of all features). It would also be really cool to see what the physical background of the index is  .

 

Just some speculation: the fact that height anomalies over Eurasia are taken into account in the OPI, might give a link to the SAI (snow advance index). Positive height anomalies above Eurasia seem to develop due to a high rate of snow accumulation over Eurasia itself. (check the post of Chionomaniac in the Stratosphere-thread to see what I mean).

 

https://forum.netweather.tv/topic/81567-stratosphere-temperature-watch-20142015/

 

If the epsilon factor (from http://app.til.it/opi/) is indeed directly related to the anomalies over the same part of Eurasia as the SAI is, then there might be a significant link between them.

 

Once again, this possibilty is only speculation, and is in no way based on physical evidence. Therefore, this possibility is nothing near a certainty.

 

And finally, once again, thanks for your elaborate post Crocodile23!

 

Sources:

https://forum.netweather.tv/topic/81567-stratosphere-temperature-watch-20142015/

http://app.til.it/opi/

Edited October 28, 2014 by Vorticity0123

[cheshire snow]

Even though i am at a total loss on this subject, this thread has been a

Pleasure to read and get some understanding on the subject

Well done to all for all the time and effort you have put in

Rgds

C.s

[radiohead]

-2.07 on the 06z

I'm honestly surprised it has been changed this much with so many consolidated days and only a few forecast days ahead.

[Skyraker]

If I understand crocs post correctly, the final opi number on the 31st will NOT be the final opi figure for the month.

[mountain shadow]

I'm honestly surprised it has been changed this much with so many consolidated days and only a few forecast days ahead.

From what I'm reading the update after each run is irrelevant, they must be, as even the swing from yesterday is much more positive than it should be as we it should be very stable by now?

 

I mentioned away back at the beginning of the thread that it isn't how the OPI begins at the start of each month, but how it ends.

 

The OPI getting less and less negative is a clear sign the vortex is getting itself together. I have to say though, i'm bamboozled by this.

[shaky]

Just had a look at the cfs nao index and the bad news is it has completely flipped to a postive outlook compared to what it was showing last week!!!also the blocked runs it was showing for the past couple of months have practically vanished!!!on the other hand the ao looks like remaining neautral to negative!!knowing our luck though that will change for the worse as well!

[ukpaul]

From what I'm reading the update after each run is irrelevant, they must be, as even the swing from yesterday is much more positive than it should be as we it should be very stable by now?

 

I mentioned away back at the beginning of the thread that it isn't how the OPI begins at the start of each month, but how it ends.

 

The OPI getting less and less negative is a clear sign the vortex is getting itself together. I have to say though, i'm bamboozled by this.

 

From my reading of Croc's post that isn't the way it is seen, it is the average of the position and angle of the PV over the whole month, the later days unable to move the figure to any great degree.