Model Output Discussion - Deeper into Autumn

[BLAST FROM THE PAST]

5 minutes ago, feb1991blizzard said:

still saying mid winter our best chance this year - xmas & jan.

Why are you saying that Feb?  I’m quite interested as I agree

 

BFTP

[Eagle Eye]

You can see the large scale WAA near Iceland in the mid term on the latest run of the GFS.

You can see that on the height anomalies, keeping the Atlantic at bay and in a decent position for a quick flip from the previous few days NAO+/blocking to a -NAO.

That's shown well by the cold air sliding in,this is a very good run if we want a pattern change and that sort of Rossby waving is bound to weaken the zonal winds. Its even a good position for the thermal gradient to be high enough for its strength to be good enough to significantly affect the Stratosphere.

If this were right into Winter, this could deliver proper snow if there was a bit more precipitation associated. Most of how cold it gets will be to do with how cold the cold pool gets and how far it can advance of course.

The eventual cold pool actually starts getting quite strong early on in the run (purples) but it weakens of course as it slides across Europe to us.

The 850s really do look decent though. A proper easterly.

And we have the Meteociel charts showing the high blocking the westerly jet mid run with the MJO phase 6-7 lag, Nino state AAM, weakened zonal winds below the Stratosphere. Its a very good setup if it can be pulled off.

It is only 1 run though but it's a step in the right direction. One small step fot the high. One giant leap for the early Winter prospects.

 

[feb1991blizzard]

Just now, BLAST FROM THE PAST said:

Why are you saying that Feb?  I’m quite interested as I agree

 

BFTP

If you look at the charts, with these blocks blocking off these quasi-stationary Atlantic troughs, its sending warm air into the Arctic, but at the moment theres no severe cold to the East, you usually need a few attempts anyway, these patterns could well trigger a mid-late December Ssw, we may not need a full on one - a minor one might do - a trop led one like a drip drop one, another wave attack just as the westerlies look to downwell.

[bluearmy]

the ext ens drift to some lowish euro heights and slp continues.  As others have noted, the modelling is keeping the Canadian vortex strong as it counts down, despite many extended ops showing it weakening. 

if we do get the euro heights playing ball later week two and we do get the scrussian ridge set and extended west, then we can see a cold pattern establish for most of europe (away from n scandi  ). The jet can happily fire away to the north - a form of ‘murr sausage’ extended from the ural high. 

even a mid lat high will bring cold surface conditions to our part of the world. 

also indications that the strat vortex is not going to go Asian for more than a day or two - this isn’t unexpected given experience - another reason to want the upper ridge to set before the jet restrengthens/ tpv moves back closer to e Canada/Davis strait 

EDIT: looking through the postage stamps T360 eps members is much more encouraging for coldies than the mean output. 

Edited November 22, 2022 by bluearmy

[SLEETY]

The Ecm is all over the place at the moment  first it showed a big Scandi block developing, then next run flat as a pancake, with no high pressure developing then yesterday evening some sort of token high pressure developing over Greenland, then this morning a messy looking Scandi High.,no faith in it currently. 

Prefer gfs and other at the moment. 

[northwestsnow]

Smart money suggests blocking in our vicinity as we head through the first week of Dec.

Very impressed with the guys who promoted the idea of a pattern change into December, a very unusual time of year to see anything but a raging +NAO.

I'm sure the most of us would prefer cool/cold and dry to this mild windy and wet gunk that has dominated for weeks ,and weeks...

 

 

[Anthony Burden]

Morning all.nothing changes in regards to  the alteration of high pressure positioning and orientation with ECM as I mentioned in my last blog  need patient’s,when we get to 96 hrs/120hrs then more reliability of where we stand.Overall looking very exciting for cold / very cold fans.

[carinthian]

On 20/11/2022 at 08:09, carinthian said:

Good morning. A lot of excitement over here with the snow prediction for this Tuesday. The North Italian Low generating plenty of moisture into the Alps. Our own fine mesh model showing 48cm of fresh snowfall by the end of Tuesday at 2000m level and 28cm in village at 1340m. Will be interesting to see how successful the predictive rates fair.  Certainly an interesting week in model watching  as we approach the first week of winter. Some of the higher resorts start the new ski-ing season next weekend . Our local experts are confident that it will be cold enough to operate the snow cannons , especially next weekend as night temps fall to quite low levels.  Looking across to Western Europe, after a rather cold start to the week , it looks like getting milder with WAA pushing north across The British Isles. This should help renew the cold block and retain snow cover across Eastern Europe. Of course ,a forecast build of pressure by the end of next week should help blighty to dry out.

C

Morning all, just an update regarding the above post. A major cyclonic storm now developing over Northern Italy. Plenty of warm moisture being transported from The Adriatic into the Austrian Alps and a lot of snowfall expected to be generated as the air meets the colder mass on the lee side as of the massive. Snow set in about an hour ago and expected to last 24 hours.  The fine mesh model latest prediction is showing 70cm at 2200m in the region. High winds could cause some instability in the snow mass later today.  Looking at the first week of December, the team over here keep the cold locked in Central Europe with some low night time temps forecast from next weekend.  At the same time strong WAA into NE Atlantic will develop a robust build of pressure across Central Britain.

C

Edited November 22, 2022 by carinthian

[Kirkcaldy Weather]

Always best to analyze any blocking setups in steps. Currently the main date looks to be November 30th (give or take a day either side) 

So looking closer at that date from the 0z GEFS mean

 

Main points are 

• Large High (strengthening) somewhere in the vicinity of our good neighbour  Scandinavia seems a good bet, theres also another mega strength block setting its sights on Siberia / parts of Asia, 1070hpa  yep there ain't nothing shifting that 
• Lowering pressure in the Mediterranean 

Whilst no weather patterns are ever identical I find it helpful to look for potential similarities in previous setups, I've seen comments that it's ridiculous to have a high in our vicinity that links all the way to our north east however that is familiar to how the 2018 beast got underway  and there's the low pressure in the med too 

I'm not quite convinced just yet that the ECM has things figured its slowly getting the idea 

The means pretty much always have a flatter setup than when the pattern actually arrives however the 0z was better than the 18z in regards to the colder flow being angled more favourably and moving in our direction 

Here's how the 0Z GEM Mean progressed things 

 Again that signal for the high to be retrogressing over toward Greenland 

The blocking charts from cpc look really awesome too just look at those spikes 

I'd say the 0z P8 GEFS is quite a fair example of how we'd be expecting things to play out 

On 18/11/2022 at 15:40, Kirkcaldy Weather said:

Once it progresses into phase 6 I'll do my outlook for that but for now I'm focusing on the most recent travels 

Any lull in our current pattern is likely to be shortlived I'd say and likely fits with the MJO moving from the western hemisphere / Africa phases into the Maritime ones

Firstly the section I've marked is phase 4 which although was brief I think still worth mentioning 

For phase 4 November the composites show ridging developing up through the UK potentially getting near to Greenland   

Dates To look for that I'd go with November 25th / 26th and the ECM overnight has a similar ridge pattern 

Phase 5 .... a few differing signals though the overlying agreement still favours blocking 

 This is not too far from our current setup with the Atlantic troughing (similar negative tilt look to it there) and high focused through Scandinavia and also more blocking throughout the Arctic 

These would see the ridging / block steadily head for Greenland  

Start looking for these patterns developing by 27th / 28th November.

As the MJO has now travelled into phase 6 Here's my outlook based on that

 Fits in with all of this Post really good,

here's another which is pretty similar also if you pair the two there's the movement nearer to Greenland  

which agrees with these  

Dates I'd look for those patterns... 3rd / 4th of December 

[TSNWK]

Gfs looks OK to me at 7 and 8.. huge high fron Azores to way into northern Russia   just a sign its building into Greenland. 

[sundog]

16 minutes ago, TSNWK said:

Gfs looks OK to me at 7 and 8.. huge high fron Azores to way into northern Russia   just a sign its building into Greenland. 

A bit off topic but wasn't it the movement  of Azores high that kicked off the cold spell mid Dec 09? Usually an enemy for coldies but that was one of the rare occasions it was a friend. 

[TSNWK]

Both GFS runs are similar out to say 10.. pressure ridges in over us towards scandi from azores.

850s generally in negative figures and I would think rather chilly with decent frost across the nation where clear sky's allow. 

[TSNWK]

3 minutes ago, sundog said:

A bit off topic but wasn't it the movement  of Azores high that kicked off the cold spell mid Dec 09? Usually an enemy for coldies but that was one of the rare occasions it was a friend. 

Not sure personally on that. However you see that present are not getting fireworks for coldies as still to much energy up top...

[ICE COLD]

Another ok ish gfs 6z run . Blocking galore

[TSNWK]

3 minutes ago, ICE COLD said:

Another ok ish gfs 6z run . Blocking galore

Be pretty darn cold I reckon with the Atlantic duvet removed and pretty much minimal solar input.  Some tasty frosts 

[IDO]

33 minutes ago, TSNWK said:

Gfs looks OK to me at 7 and 8.. huge high fron Azores to way into northern Russia   just a sign its building into Greenland. 

Yes, post D8 is still up for grabs. There is no clear obvious outcome as further waves of high pressure push into our sector. Just look at the busted jet and the cold leaking south on the NH profiles:

T300 JFF GFS op 06Z: 

Even with no classic HLB'ing, there is scope for a cold flow if the pieces fall right.

[Yarmy]

24 minutes ago, sundog said:

A bit off topic but wasn't it the movement  of Azores high that kicked off the cold spell mid Dec 09? Usually an enemy for coldies but that was one of the rare occasions it was a friend. 

Sort of, but the whole Northern Hemisphere profile was more or less split in two.

[sheikhy]

That scandi high is HUUUUGE on the gfs mean at 192 hours!!and where does the battle take place?!yep you have guessed it...........

 

[TSNWK]

20 minutes ago, Yarmy said:

Sort of, but the whole Northern Hemisphere profile was more or less split in two.

Yes that's why no fireworks with this heights forecast.. there is too much happening to our north that prevents the moneyshot charts..

[minus10]

31 minutes ago, IDO said:

Yes, post D8 is still up for grabs. There is no clear obvious outcome as further waves of high pressure push into our sector. Just look at the busted jet and the cold leaking south on the NH profiles:

T300 JFF GFS op 06Z: 

Even with no classic HLB'ing, there is scope for a cold flow if the pieces fall right.

Yes the jet is in tatters over our side of the hemisphere..that has to be a good sign going forward doesnt it? ...

[Frigid]

22 minutes ago, sheikhy said:

That scandi high is HUUUUGE on the gfs mean at 192 hours!!and where does the battle take place?!yep you have guessed it...........

 

1060mb high nearby 

 

 

 

 

Edited November 22, 2022 by Frigid

[IDO]

4 minutes ago, minus10 said:

Yes the jet is in tatters over our side of the hemisphere..that has to be a good sign going forward doesnt it? ...

A split/broken jet will mean better probability of no Euro heights, with any highs at mid-lat, which is demonstrably easier and faster to develop better northern blocking, if at all possible.

The Control beings in an easterly from D8:

D11 GFS control 06z: 

[Methuselah]

Well, my personal thought is that the GFS 06Z Op is a bit of a mess, with (apart from the obvious blocking) no concrete indication of what lies ahead... At T+384, those pesky warm uppers are starting to gather toward the Med?

    

    

    

Although, I'm sure we all realise just how infallible T+384 charts aren't!

[Allseasons-Si]

Look at this stonker P17,...total -AO carnage 2010 style

[Mike Poole]

GEFS mean T336.

 

This looks improved over the 0z in terms of Atlantic ridge and position of the main vortex - away from Canada.