Model Output Discussion - Autumn 2018

[ItNeverSnowsInWindsor]

Another major warm outlier from the GFS 0Z. Expect some changes in the coming days to show more dips.

[carinthian]

27 minutes ago, carinthian said:

Morning all. Regarding the above post, just this time last week most models were showing retrogression of the European high into October. This chart below from UKMO shows the reverse with  a strong build of pressure remaining in situ. Nice weather  where you get the sunshine but a bit of a October bore fest for those stuck under cloud and nothingness, if you know what I mean. However, despite all the numerical predictions of Leslies eventual track in 7 days time, wind data as highlighted in the above post remains sparse and the picture could well look completely different in the models this time next week.

Certainly no October Bore fest over in Calgary last night. 20 -30cm fresh snowfall. A different climate in the Prairies !

[tight isobar]

The mean takes away its clusters...'somewhat'!..

And an-elevation non-maxima applys...

Mjo signal starts its phasing ...

And has a defined, momentum.

And highlights the blocky signal...angular momentum and high/mid-lattitude format in a desirable place for the time in place...

Russian pen-/and pacific ridging will be of massive/paramount this season.

We'll take all other telecons-parameters as they evolve....

Likely an early notable cold snap into NW-europe should things keep the Balance!!..

Arctic anoms also of major note...

The (pv) is in a state of mass confuse at this point....'given'- its trying to evolve and counter.....however basin complexities and the already mentioned....

Certainly a-desirable juncture to view....as winter steps in....

 

 

Edited October 4, 2018 by tight isobar
Adding

[Coopsy]

1 hour ago, carinthian said:

Certainly no October Bore fest over in Calgary last night. 20 -30cm fresh snowfall. A different climate in the Prairies !

60cm's at my friends place in Kananaskis  - 45 mins from Calgary in the foothills of the Rockies. 45cm's at my place in Canmore. The highways were a mess.

Edited October 4, 2018 by c00ps

[carinthian]

11 minutes ago, c00ps said:

60cm's at my friends place in Kananaskis  - 45 mins from Calgary in the foothills of the Rockies. 45cm's at my place in Canmore. The highways were a mess.

Great photos. I live at a height higher than Canmore and have never seen snow like that in early October ! 

C

[Interitus]

35 minutes ago, tight isobar said:

 

Where does April's ice thickness come into it?

[Coopsy]

5 minutes ago, carinthian said:

Great photos. I live at a height higher than Canmore and have never seen snow like that in early October ! 

C

To be fair that's more like a spring snowstorm so was unusual for the time of year. Here's hoping the set up is right for Europe this year that we all get to share in this type of weather

[tight isobar]

59 minutes ago, Interitus said:

Where does April's ice thickness come into it?

Used aprils as 'a' scope on my analysis!..

Ie depletion of thickness values!!..

It sums the back end of northern hemispheric winter sorts!..

And with being in the incorrect 'thread'.. i'll bang the drum b4 moving on...

Melt/depletion imo..is an Axis phase...along with a solar/geo-mag min.

In a nutshell- cause and purpose for a sea/maritime cooling effect that magnifies, a mid/upper latt downward trend overall.

Thus climate change....not GW!??

AND yes the depletion continues...just a crying shame some dont/refuse to see the real climate impacts...without jumping on the blinkered TAX wagon!!!!

Regards.

Edit; a brief yet descript evaluation of your question.

Edited October 4, 2018 by tight isobar

[summer blizzard]

As mentioned last night. GFS hinting at building to the north and east in FI..

[sebastiaan1973]

7 minutes ago, summer blizzard said:

 

As mentioned last night. GFS hinting at building to the north and east in FI..

 

That's in good agreement with the EC-seasonal forecast for october. 

 

https://weather.us/monthly-charts/euro/europe/anomaly-msl/20181001-0000z.html

Edited October 4, 2018 by sebastiaan1973

[tight isobar]

Anyway..winding and morphing going forwards...could be talk of the town!

Atlantic starting 2 buzz..and a likely response to lower/equatorial weighing!!..

Watch this one...a create of its own!..

Landfall apply will be critical!!!..

[ItNeverSnowsInWindsor]

1 hour ago, c00ps said:

60cm's at my friends place in Kananaskis  - 45 mins from Calgary in the foothills of the Rockies. 45cm's at my place in Canmore. The highways were a mess.

We need some early snow here badly!

[mb018538]

ECM clusters....day 10. On a knife edge:



Split down the middle whether the low or the high has the greater influence. Going to be a few days to sort this one out i feel.

[Frosty.]

The Ecm 00z ensemble mean indicates a NW / SE split with some fine and warm spells further s / se and a generally cooler changeable / unsettled picture further n / nw.

Edited October 4, 2018 by Frosty.

[feb1991blizzard]

Truly awful charts if your looking for a good winter - very early to be having such an organised vortex right over the pole - OPI in excess of 2 I should think by this timeframe.

[Methuselah]

10 minutes ago, feb1991blizzard said:

Truly awful charts if your looking for a good winter - very early to be having such an organised vortex right over the pole - OPI in excess of 2 I should think by this timeframe.

Utterly irrelevant IMO - it's still only early October, for God's sake!

[feb1991blizzard]

Just now, Ed Stone said:

Utterly irrelevant IMO - it's still only early October, for God's sake!

OPI is very relavent = a significantly positive value for the whole month gives a 100% correlation with a non-cold snowy winter.

[Methuselah]

2 minutes ago, feb1991blizzard said:

OPI is very relavent = a significantly positive value for the whole month gives a 100% correlation with a non-cold snowy winter.

100%? Yeah, right.

[Yarmy]

13 minutes ago, feb1991blizzard said:

Truly awful charts if your looking for a good winter - very early to be having such an organised vortex right over the pole - OPI in excess of 2 I should think by this timeframe.

Ugly indeed, yet if you look at the height anomaly over the Taymyr peninsula for the same time:

 

...it's not so bad, and - as referenced on the Analogues thread - the TCA appears to be the best performing of the precursor methods for predicting the winter AO. Seems like there's a new index for this every year though, SCE (snow cover extent), SAI (snow advance index), OPI, POL,...

[Interitus]

22 minutes ago, feb1991blizzard said:

OPI is very relavent = a significantly positive value for the whole month gives a 100% correlation with a non-cold snowy winter.

How are you calculating the OPI? The workings weren't made clear and it promptly failed at the first forecast hurdle.

Anyway the Taymyr index, POL or whatever aren't foolproof for the UK as they link to AO. October 62 had a low geopotential anomaly -

Edited October 4, 2018 by Interitus

[feb1991blizzard]

1 minute ago, Interitus said:

How are you calculating the OPI? The workings weren't made clear and it promptly failed at the first forecast hurdle.

Anyway, the Taymyr index, POL or whatever aren't foolproof for the UK either as they link to the AO - October 62 had a low geopotential anomaly -

Its easy to tell by height charts when the OPI is strongly positive or negaitive - its less clear when its borderline (ie - neutral), yes it failed but it wasn't foolproof when it was negative, but I do remember when it was quite positive, it was near nailed on - I don't think the OPI was available for data in years prior to the late 70s, I will have to go through it again when I get chance.

[Methuselah]

2 minutes ago, feb1991blizzard said:

Its easy to tell by height charts when the OPI is strongly positive or negaitive - its less clear when its borderline (ie - neutral), yes it failed but it wasn't foolproof when it was negative, but I do remember when it was quite positive, it was near nailed on - I don't think the OPI was available for data in years prior to the late 70s, I will have to go through it again when I get chance.

What's the actual number of winters for which the correlation holds, feb? 

[Interitus]

2 minutes ago, feb1991blizzard said:

Its easy to tell by height charts when the OPI is strongly positive or negaitive - its less clear when its borderline (ie - neutral), yes it failed but it wasn't foolproof when it was negative, but I do remember when it was quite positive, it was near nailed on - I don't think the OPI was available for data in years prior to the late 70s, I will have to go through it again when I get chance.

Yes, people were seeing the figures and matching them to the charts - and it failed. Nobody looked back at the years where it seemed to work to see if it was genuine. It would be easy to do from reanalysis data but the exact method wasn't made clear.

[No Balls Like Snow Balls]

I thought the OPI had fallen out of fashion, after that disastrous winter where, well the Thames should have frozen over, but ended up complete opposite.  

[feb1991blizzard]

6 minutes ago, Interitus said:

Yes, people were seeing the figures and matching them to the charts - and it failed. Nobody looked back at the years where it seemed to work to see if it was genuine. It would be easy to do from reanalysis data but the exact method wasn't made clear.

You do have a point there.

 

8 minutes ago, Ed Stone said:

What's the actual number of winters for which the correlation holds, feb? 

Don't know, I will have to look back, perhaps the thread should be re-opened so we can debate it. Anyway Pete its unlike you to dispel anything that points to mild weather, if your forecasts in the climate science section are correct, then Northern Greenland get your BBQ's out by the year 2100.