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

[karyo]

-2.86 based on the 12z

 

The 12z was not as good in the polar field and considering a couple of days ago we had sub -3, this is a trend we don't want to continue.

Edited October 18, 2014 by karyo

[shaky]

-2.86 based on the 12z

 

The 12z was not as good in the polar field and considering a couple of days ago we had sub -3, this is a trend we don't want to continue.

still a pretty darn good negative opi and we are 3/4 of the way through ocotber nearly!!!

[karyo]

still a pretty darn good negative opi and we are 3/4 of the way through ocotber nearly!!!

Agreed but I guess this is largerly thanks to the pattern we had so far and if the low pressure takes hold in the Arctic like the GFS suggests then this can do a lot of damage to the final figure! Let's hope the GFS is overdoing it.

[Tom Quintavalle]

As Lt.Colonel Guidi has been kind enough to agree to join the forum to explain a little more regarding the Italian teams research into the OPI, here is a little clip of him on Italian TV.

Lt.Colonel Guidi is a member of the Aeronautica Militare (Italian Air Force) and members of the Italian Air Force often present weather forecasts on Italian TV.

 

I hope Guido doesn't mind me posting this on here and perhaps those of you who have a little knowledge of Italian can get the gist of what he's saying.

 

http://www.youtube.com/watch?v=dKJ6kclHvDU&feature=player_detailpage

 

Regards,

Tom.

[karyo]

As Lt.Colonel Guidi has been kind enough to agree to join the forum to explain a little more regarding the Italian teams research into the OPI, here is a little clip of him on Italian TV.

Lt.Colonel Guidi is a member of the Aeronautica Militare (Italian Air Force) and members of the Italian Air Force often present weather forecasts on Italian TV.

 

I hope Guido doesn't mind me posting this on here and perhaps those of you who have a little knowledge of Italian can get the gist of what he's saying.

 

http://www.youtube.com/watch?v=dKJ6kclHvDU&feature=player_detailpage

 

Regards,

Tom.

I was watching those Italian weather forecasts (Rai Uno) as a kid and I was fascinated with their detail and professionalism! The ones in Greece were always basic and brief!

 

[Mucka]

I hope Lt.Colonel Guidi's first name is Guido and that is not Italian a formal address for presenter or guide or moderator or something.    

Not heard anything more since  but if you have a question just post it and he can answer when he comes on.

Edited October 18, 2014 by Mucka

[KyleHenry]

Question for Lt Col Guidi

Q. Does the solar cycle- sun spot numbers/ planetary AP Index have any relationship to the OPI at the data input stage of the modelling?

[MarkTJ]

Can someone post the link to the OPI update please. Many thanks

[Mucka]

Can someone post the link to the OPI update please. Many thanks

 

It was in the OP

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

Edited October 18, 2014 by Mucka

[MarkTJ]

Cheers Mucka

[Blessed Weather]

Based on today's GFS 12z output, the run-in to the month end Index might be a nervous time. Comparing the GFS ensemble mean for tomorrow with the 31st Oct is like chalk and cheese and shows the heights have pretty much disappeared from the vicinity of the Pole by months end (although at least the most deterioration is between 27th and 31st Oct so possibly limiting impact on the Index). But as others have noted, compared to other models, today's GFS might be too progressive.

 

GFS ensemble mean 19th Oct:   31st Oct:

[karyo]

Based on today's GFS 12z output, the run-in to the month end Index might be a nervous time. Comparing the GFS ensemble mean for tomorrow with the 31st Oct is like chalk and cheese and shows the heights have pretty much disappeared from the vicinity of the Pole by months end (although at least the most deterioration is between 27th and 31st Oct so possibly limiting impact on the Index). But as others have noted, compared to other models, today's GFS might be too progressive.

 

GFS ensemble mean 19th Oct: GFS Rnz500m1 ENS Mean 19Oct2014.gif  31st Oct: GFS 12z Rnz500m13 for 31Oct2014.gif

If it proves correct, it will also wipe out a lot of the snowcover gains in Eurasia!

[bluearmy]

If it proves correct, it will also wipe out a lot of the snowcover gains in Eurasia!

Not sure about that karyo. Will take a big change to remove much of the cover accumulated thus far. Much further west and southwest, a strong possibility.

[karyo]

Not sure about that karyo. Will take a big change to remove much of the cover accumulated thus far. Much further west and southwest, a strong possibility.

I am not saying it will wipe it out completely but can do a lot of damage so we may lose the positive snow cover anomalies. Western Russia will lose it's snow cover first if the gfs got it right and as the westerly/southwesterly looks rather deep, the snow loses will extend further east.

[Gael_Force]

Based on today's GFS 12z output, the run-in to the month end Index might be a nervous time. Comparing the GFS ensemble mean for tomorrow with the 31st Oct is like chalk and cheese and shows the heights have pretty much disappeared from the vicinity of the Pole by months end (although at least the most deterioration is between 27th and 31st Oct so possibly limiting impact on the Index). But as others have noted, compared to other models, today's GFS might be too progressive.

 

GFS ensemble mean 19th Oct: GFS Rnz500m1 ENS Mean 19Oct2014.gif  31st Oct: GFS 12z Rnz500m13 for 31Oct2014.gif

 

An ensemble mean is far too blended to be much value in thirteen days time - look at the postage stamps for the individual members - any manner of pattern but none like the mean blob which is third from right on the bottom row.

 

[DOdo]

we will just have to wait and see, 

[mountain shadow]

Based on today's GFS 12z output, the run-in to the month end Index might be a nervous time. Comparing the GFS ensemble mean for tomorrow with the 31st Oct is like chalk and cheese and shows the heights have pretty much disappeared from the vicinity of the Pole

Well, by my understanding of the OPI, this is nonsense, otherwise we might as well just measure the index on the 12z on the 31st October.

[Mucka]

An ensemble mean is far too blended to be much value in thirteen days time - look at the postage stamps for the individual members - any manner of pattern but none like the mean blob which is third from right on the bottom row.

 

 

Yeah I really think GFS FI output over the last couple of days should be taken with an even larger dose of salt than usual - it has little support from the other models even by day 5/6 and it breaks down the Scandi ridge and shunts the pattern East far too quickly. All that makes a big difference the pressure profile over the Arctic. The 18z looks a little more realistic so far but of course the OPI isn't calculated for the 18z.

I wonder what happened to our Italian friend?

Edited October 18, 2014 by Mucka

[Wilxy]

18z GFS shows much more heights heading towards the pole so far which is closer to the GEM solution as it stands.

Edited October 18, 2014 by tomjwlx

[Yarmy]

18z GFS shows much more heights heading towards the pole so far which is closer to the GEM solution as it stands.

Yes, you beat me to it. Very split vortex. 18z isn't used for the OPI as we know, but hopefully the future runs will follow this trend. (As ever, the usual caveats apply)

[bobbydog]

Well, by my understanding of the OPI, this is nonsense, otherwise we might as well just measure the index on the 12z on the 31st October.

 

 i dont think anyone here really understands the OPI.

the 10 day forecast part, seems to make less sense the more we try to understand.

 

take the SAI for (a very relevant) example.

it is calculated by taking the actual figures for snowfall in the relevant areas, for each day throughout october, then on the 31st, when we have the complete data, the index can then be fully calculated.

the OPI, by comparison, (if we even understand the basic principle) should be calculated by taking the actual daily figure over 31 days to complete the data required for the final value. the forecast, however accurate, is still only speculation. why bother using it at all when the final value cannot be calculated until the 31st by which time, all of the actual data is available anyway?

[Woollymummy]

Maybe to see if the final value becomes clear at some point during the month? Maybe it doesn't change much after the third week of October? Or the second?

[bobbydog]

Maybe to see if the final value becomes clear at some point during the month? Maybe it doesn't change much after the third week of October? Or the second?

 

possibly, it shouldn't change much after the third week anyway but it only becomes fully clear on the 31st, when all of the actual data is available. point is, why use a forecast for 10 days out which could be completely wrong by then, to create a daily figure, when each day there is a real outcome anyway. it would make a bit more sense if the use of forecast data was started on the 21st, to give an estimate of the final value but anything before that seems pointless.

[LomondSnowstorm]

Maybe to see if the final value becomes clear at some point during the month? Maybe it doesn't change much after the third week of October? Or the second?

Last October it stabilised around the 18th, although that was perhaps more due to the pattern being particularly stable.

I think that we might be starting to see the final value stabilising - the most progressive run of today produced an OPI that was only 0.5 greater than the most negative value of the last two days, which suggests that it's quite likely to end up sub -1.5 even if the month ends poorly with a vortex starting to get its act together. However, clearly the lower the value the more likely it is for us to get significant vortex disruption, and also the more likely we are to keep a hold of, and even expand, the massive Eurasian snow pack we have at the moment. On that, the jury is out, but the fact that runs where the vortex is close to 'normal' by the end of FI are in a minority suggests that we may yet manage to ride our luck with regard to snow cover and the OPI value right out to the 31st.

[LomondSnowstorm]

possibly, it shouldn't change much after the third week anyway but it only becomes fully clear on the 31st, when all of the actual data is available. point is, why use a forecast for 10 days out which could be completely wrong by then, to create a daily figure, when each day there is a real outcome anyway. it would make a bit more sense if the use of forecast data was started on the 21st, to give an estimate of the final value but anything before that seems pointless.

Agreed, would be useful to see the actual values. There might be good reasons, pertaining to the fact that this is still in its development stage without a paper on it published so far, why they aren't released, but if it is just a presentational choice I'd politely suggest that they change it to include actual daily values alongside forecast values.