Model Output Discussion - Into Autumn 2019.

[Methuselah]

Two trends seem apparent, from the GEFS 06Z ensembles: a general rise in SLP from the 26th, and an overall decline in temperature...Autumn's coming!

   

   

I wonder how many of those aforementioned 'trends' will survive the next run?

[MP-R]

1 hour ago, Steve Murr said:

Define unusual-

Based on that - from 1999 - 2019 covering 20 years find how many high pressures you have in that general locale of Greenland East to The west coast of Norway you will find a very small sample size especially late sept - there for it is unusual - even more unusual if you compare back to 1948.

There is a caveat that if you shorten the timeline & sample size say back to 2009 where late Autumn blocking has been more apparent then it would appear to be less so....

As highlighted though the model contradicts what you are saying by its clarity in the anomaly chart being so distinct - if it wasnt so unusual the chart would be diluted.

The updated 06z anomaly chart showing further still how inverse things are V the norm

I think you’ve answered your own question.  This also wasn’t my original rebuttals. Granted I can think of more examples of highs in that area in October and November than September but that’s for another thread.

So I’ll repeat for one final time - weather off the Atlantic in mid/late September is hardly against the norm. 

[Polar Maritime]

A few posts have had to go as off topic, Please continue with Model Discussion.

Thank you all.

[MATTWOLVES 3]

Absolutely gorgeous here today, and more of the same till Saturday. Next week looking much more autumnal, especially further NW. Temps probably back around average at this stage.... Tentative signs of high pressure building from the SW into the following week... Perhaps one more decent settled spell before the fall takes over!! On a parting note I can't believe their is serious discussion regarding the upcoming winter at this stage!! Even one post claiming winter could be scuppered already!!! Really!!! Give me a break... Its nearly 3 months away.... Let's not get the valium out just yet guys.... Enjoy the next couple of days. 

[ItNeverSnowsInWindsor]

We need to see blocking towards Iceland and Greenland in October as early signs of a cold winter as in 2009 during the time the Icelandic volcano ashes caused flights to be cancelled. Current signs of blocking look favourable so far.

[SMU]

Updated 12z models point to continued focus for pressure rises to the North in the vicinity of Greenland & Scandi -

Highlighting the point of 'unusualness' in 2 other ways -

NAO at this time of year should be escalating upwards from the neutral to +0.5 zone over summer ( historic mean as an estimate ) to the some sort oscillation between +0.5 > + 1.5 ..

Todays NAO ensembles driven by the 00z GFS sees the metric tanking with time heading towards a region of -1 to -2, that is a standout deviation from the norm -

Also captured from the other snow thread - the northerly locale of High pressure has been so 'unusual' in its placement North & West that Sweden are recording their earliest snow in X2 decades...

https://electroverse.net/september-snow-in-sweden-earliest-in-at-least-20-years/

The correlation to the UK & winter at this early juncture is not precise - not even 0.5

All it is however is highlighting the possibility of whats to come over Autumn- 

& * maybe * winter- Discussion of which can be made in more depth in the other threads.

[feb1991blizzard]

She is on her way!

[Zak M]

Hello all. This is my first ever post on this thread

Just had a look at the Sypnotic Fax charts, and over next week it looks quite interesting. An area of high pressure is currently in charge, and will remain so for the next couple of days. On late Saturday onwards an area of low pressure bringing bands of heavy and persistent rain will start to edge in from the SW. Early next week, another low pressure which is said to be Ex-Humberto will once again bring heavy and persistent rain to most parts of the UK.

Sorry if this post looked a bit dodgy, I'm still trying to expand my knowledge of all these weather charts, so please bare with me 

[feb1991blizzard]

Screaming North / North Easterly in-bound.

Could we have an early one of these flashing??

 

 

Edited September 19, 2019 by feb1991blizzard

[Daniel Finch]

*cough* *cough* It's September *cough* *cough* 

[feb1991blizzard]

Either way the models are suggesting some lovely early snow cover build up over Scandi, cannot see it realistically lasting through Autumn but wonder if it will have any effect  on the SAI, OPI and the siberian high as we go through Autumn.

Edited September 19, 2019 by feb1991blizzard

[Methuselah]

Aye, aye! The October Fog Index might get off to a flyer...?

   

[Mair Snaw]

Didnt we get caught out by the OPI a few winters ago? everybody was on tender hooks for the entire month and we ended with a big minus figure only for the following winter to be a massive bust? and can somebody tell me what the SAI is? not sure ive heard of that. will help with following this thread as we tick down into winter. cheers

[SMU]

2 minutes ago, bigsnow said:

Didnt we get caught out by the OPI a few winters ago? everybody was on tender hooks for the entire month and we ended with a big minus figure only for the following winter to be a massive bust? and can somebody tell me what the SAI is? not sure ive heard of that. will help with following this thread as we tick down into winter. cheers

Snow advancement index

[Mair Snaw]

1 minute ago, Steve Murr said:

Snow advancement index

Can that be followed in the snow and ice in the northern hemisphere thread?

[Kirkcaldy Weather]

4 minutes ago, bigsnow said:

Didnt we get caught out by the OPI a few winters ago? everybody was on tender hooks for the entire month and we ended with a big minus figure only for the following winter to be a massive bust? and can somebody tell me what the SAI is? not sure ive heard of that. will help with following this thread as we tick down into winter. cheers

"Snow Advance Index: A New Tool for Predicting Winter’s Severity" https://www.aer.com/news-events/blog/snow-advance-index-new-tool-predicting-winters-severity/

[Mapantz]

We've got various threads for discussing the the SAI, Siberian high and a defunct OPI and this isn't one of them. Please use the PM function if it's necessary. Thanks.

[SMU]

1 minute ago, bigsnow said:

Can that be followed in the snow and ice in the northern hemisphere thread?

Yes - If you follow Judah cohen on Twitter he usually formulates a graph ---

[Frosty.]

The earlier GEFS showed some wintry interest in very early october and the 12z does too!!.. you probably think I'm crackers but I'm just limbering up for winter!!❄

 

[Methuselah]

Well, the GEFS 12Zs have further amplified the early October pressure-rise, though the 850s continue their steady decline into Autumn proper...

   

The location/orientation of the resulting anticyclone would obviously dictate temperatures, and the likelihood (or not) of a possible fog-fest.

   

In the meantime, there are some tasty, much-needed rain-spikes forecast for next week!

 

[Catacol]

Evening all - the next winter rollercoaster is not a million miles away now. From mid October the excitement builds.

Nothing too much to comment on at the moment at this very very early stage, but as I posted a couple of times over the summer we have had a recurring -NAO pattern for a few months now, we are approaching the crunch years for those who believe in solar cycle influence, and to my eye the jet remains unusually "wavy". ENSO looks neutral and the QBO may be descending easterly by mid winter though maybe not quite early enough to influence the pattern until Spring. In addition we have long range models tilting towards a +NAO profile for DJA, though at this range that is hardly a reason to be gloomy.

As ever we have signals that are a mix of the uncertain and the inconclusive - but maybe come November a pattern may develop to whet the appetite. We also know that our 21st century world is predisposed to extreme events as climate change develops (Spain the latest victim) and this adds elements of variability that means we cannot ever be sure what is around the corner, even in a warming world. We will have extreme winter moments in the coming years for sure....and 2019/20 might contain one or more such examples.

All good fun - even when passions run high. 

[damianslaw]

Quite a change forecast next week, from this week's anticylonic nature, to a cyclonic one - with heights building strong to our north and north west, locking the trough and slow moving low pressure over the UK. Quite an interesting pattern, not your usual atlantic steamrolling in on a westerly trajectory - indeed this has been the theme of the year as a whole since February..

Tomorrow and Saturday and Sunday quite likely to bring the last of this years true warmth, yes we can still see mid 20s temps well into October, but chances become much slimmer and by then they won't feel the same as they do in September with lower light levels, and a weaker sun. Best make the make of it - will be a good six months before chances of similiar feeling weather will be back.. though we did see conditions on a par in late Feb this year.. the number of southerly outbreaks this year with low pressure to the SW and heights to our east has been very notable..

[Allseasons-Si]

There has been some good post's in here this evening,i wonder why

everyone would be mistaken that it's November with charts churning out like they have been this evening but they are good to look at at this early juncture,i am on board because as soon as we can cool Europe down the better and what is showing in the models,that could happen

lets have a look at some charts-

the latest from cpc 6-10 and 8-14 day outlooks shows a trough/low over the BI heading SE later with pressure building NW into Greenland and into the arctic with PV(polar vortex) mostly over the Siberian/Russian area

ecm/gfs at day ten have there differences but....

the means at day ten look similar to the cpc anomaly charts posted above with PV mostly over the Siberian sector 

i am looking forward to a fine old day on Saturday and then some storms potentially on Sunday before things go downhill through the week,typical that i am on mornings.

@Catacol and @Steve Murr,nice to see you posting again,cheers.

 

Edited September 19, 2019 by Allseasons-si

[feb1991blizzard]

Here we go winter fans - up and running properly?   Yes Sir!

 

[Spikecollie]

Storms on Sunday?