Model Output Discussions 06z 04/11/16

[northwestsnow]

6Z continues the general idea, and i like it, a lot !!

Hopefully the pro's will make the same noises in the coming days, you can see the building blocks towards a cooler/colder spell in the medium to long term .

I can certainly see the potnential for a Greeny high towards the back end of November, sounds better than the back end of June !

[daz_4]

Also nice to see some warming in strat starting as soon as 288h and not the usual 384h 

[bobbydog]

1 minute ago, daz_4 said:

Also nice to see some warming in strat starting as soon as 288h and not the usual 384h 

Oh wow, that's very promising 

[Ali1977]

So many different ensemble members that differ at 192 I don't think we can really look beyond and get an accurate forecast - in the long run it does seem to look good for some kind of blocking, as the METO have predicted. Nothing really cold showing up just yet but once we have some blocking in the NH this can quickly change.

Edited November 13, 2016 by Ali1977

[legritter]

Well going back to my comment on recent GFS run ,it gives some clues as apposed to any answers and all looking very interesting i must say .

Think we can expect some wild swings from the models from now on .Biggest puzzle to me is where does any block set up further down the line as hinted at in much further outlook which us morsels dont get to see at this range ,will it benefit [if you are in to coldcamp]  our friends in Greece , Balcans , scandinavia ,russia ,central Europe ,or even us SNOW COLD starved people here in the good old UK .Think its time to hide the Razors away , put the prozack out of reach , buy some straws and stock up on soup , great gang that we have some very interesting times ahead .

[Zakos]

 

ECM and GFS +192, still agreeing on an area of low heights over Greenland being displaced and moving southwards across the UK.

Both models at day 10 show a resurgence of blocking in the atlantic, and I believe both models are showing high pressure starting to build, centred just to the North/North West of the UK.

The GFS is certainly showing this in its later frames and has been for a while now. Its been showing a large positive anomaly over the most of the atlantic. The 00z Would be far better the UK, hugh anomaly over Greenland and the block is far west enough to bring some true arctic air to the UK. 

The GFS 00z ensemble mean show a clear trend towards a weakening jet stream. Cold is by no means guaranteed for the UK. but I'm seeing very little sign of atlantic weather taking hold towards the end of November.

The mean certainly indicates the core of the Polar vortex will stay within siberia, with a solid signal for blocking to our North West.

The AO and NAO are both set to dive negative, but just how negative will they go? Interesting model watching  period coming up I think.

 

[Zakos]

Much the same from the 06z ensembles.

going...going...Gone!

[Ali1977]

A snap shot of the Ensembles in FI point one way - blocked. Not much Purple and Blue on these!!

Edited November 13, 2016 by Ali1977

[Scandinavian High.]

Yep they are very interesting model watching coming up great to see you back Ali1977

[gottolovethisweather]

31 minutes ago, Ali1977 said:

So many different ensemble members that differ at 192 I don't think we can really look beyond and get an accurate forecast - in the long run it does seem to look good for some kind of blocking, as the METO have predicted. Nothing really cold showing up just yet but once we have some blocking in the NH this can quickly change.

 

 

 

That is a fair point, the 17th through to the 20th November looks highly likely to be a cooler spell of showery precipitation, often cold enough for snow on high ground, alongside some drier interludes, Temperatures well below normal up North and just below average further South. The specifics aren't worth worrying about right now, as the 850s could end up favourably for more of the UK population at large nearer the time. As the Captain states up thread, I think a drier spell with bright sunshine and hard frosts might be the new trending scenario beyond D10 into the end of the month.

Edited November 13, 2016 by gottolovethisweather

[Frosty.]

The Ecm 00z shows increasingly low thicknesses from thursday through sunday with 524-528 dam so a cold spell is on the way from the NW with precipitation becoming more wintry during this period, especially for the north and high ground where snow is likely..and we would all see a return of frosts following the milder mon / tues, all this is a nice little bonus before the meteorological winter begins!

[bluearmy]

Waiting to see the bias corrected gefs but note at the end of the run that the development of a distinct Newfoundland upper trough throws up WAA, sharpening the Atlantic ridge into Greenland and downstream troughing 

inpressive for a mean/anomoly at 16 days 

the bias corrected is not as sharp on either the ridge or downstream trough but broadly on the same page. The new month could well introduce proper winter !!

Edited November 13, 2016 by bluearmy

[Severe Siberian icy blast]

36 minutes ago, Zakos said:

Much the same from the 06z ensembles.

going...going...Gone!

I have to say. I'm absolutely gobsmacked by the state of the northern hemisphere this year. It's been a very very long time since iv saw a jet stream that doesn't actually exist. 2010 I think was the last time I saw that in winter. Just remarkable. 

Great for winter weather for us snow loving freaks lol but really quite worrying to see such an abnormal 3 wave pattern dominating the hemisphere at a time when the vortex and jet stream should be rampant. 

[Snowy L]

Think we need to get the expected wind reversal, due sometime in the 4th week of November before we can get any clarity from the models.

 

 

[bluearmy]

Just now, Snowy L said:

Think we need to get the expected wind reversal, due sometime in the 4th week of November before we can get any clarity from the models.

 

 

That assumes a strong connect between the upper strat and trop which isn't required. The strat profile n of 50/60 degrees is very slack at the moment. The trop will pretty well do as it wants without any contradiction from the strat. 

See matt's recent post in the strat thread 

[Frosty.]

Reading between the lines, there are indications that more energy will be pumped into the southern arm of the jet through the mid / longer range with Atlantic depressions on a more southerly track with a higher chance of leading edge snow for central and southern uk as systems bump into colder air. The northern arm of the jet would weaken considerably with high pressure developing to the north of the uk..that's how I read it, it could also mean height rises to the northwest, around Greenland / Iceland with northerly (arctic) incursions at times too which I understand the EC32 / GloSea5 are hinting at..IMO the smoke / fog is clearing a little and the longer term trend is becoming clearer..and it looks much better regarding December's prospects than last year's horror!

Edited November 13, 2016 by Frosty.

[northwestsnow]

1 minute ago, Frosty. said:

Reading between the lines, there are indications that more energy will be pumped into the southern arm of jet through the mid / longer range with Atlantic depressions on a more southerly track with a higher chance of leading edge snow for central and southern uk  as systems bump into colder air. The northern arm of the jet would weaken with high pressure developing to the north of the uk..that's how I read it, it could mean height rises to the northwest, around Greenland / Iceland with northerly (arctic) incursions at times too.

Absolutely Frosty- the meto update now mentioning snow on the hills later this week and the magic snow word again towards the end of November for the north.

Exciting times!!

[nick sussex]

It seems as if the models are determined to deliver a sloth like movement to any more deeper  colder conditions.

Still some uncertainty with where that low goes that drops down from southern Greenland, both the ECM and GFS fill that slowly. And then its a case of seeing what develops. Theres no suggestion of the PV firing up which is good news.

Looking at the ECM ensemble spreads the main uncertainty is to the west and nw of the UK and that would be in relation to that low.

Earlier some colder conditions showing up with some snow possible to higher ground in the far north and Scotland. But in terms of anything more substantial that's still not likely before the end of November.

[ArHu3]

1 hour ago, Zakos said:

 

ECM and GFS +192, still agreeing on an area of low heights over Greenland being displaced and moving southwards across the UK.

Both models at day 10 show a resurgence of blocking in the atlantic, and I believe both models are showing high pressure starting to build, centred just to the North/North West of the UK.

The GFS is certainly showing this in its later frames and has been for a while now. Its been showing a large positive anomaly over the most of the atlantic. The 00z Would be far better the UK, hugh anomaly over Greenland and the block is far west enough to bring some true arctic air to the UK. 

The GFS 00z ensemble mean show a clear trend towards a weakening jet stream. Cold is by no means guaranteed for the UK. but I'm seeing very little sign of atlantic weather taking hold towards the end of November.

The mean certainly indicates the core of the Polar vortex will stay within siberia, with a solid signal for blocking to our North West.

The AO and NAO are both set to dive negative, but just how negative will they go? Interesting model watching  period coming up I think.

 

This is average of ensemble, you can't do that with pressure or vectors, since they start cancelling each other more and more. In any run after 15 days there is almost no weather just a gradient from pole to equator if you look at ensemble mean

[Zakos]

3 minutes ago, ArHu3 said:

This is average of ensemble, you can't do that with pressure or vectors, since they start cancelling each other more and more. In any run after 15 days there is almost no weather just a gradient from pole to equator if you look at ensemble mean

Technically you are right, but the amplified pattern over the atlantic indicates a ridging in the atlantic is likely, with low heights more likely over europe.

 The deep blue/purple colours are centred over eastern siberia, indicating this is where most of the ensembles show the Core of the PV to be placed.

Yes, they do not show actual weather conditions, but I believe they indicate a definitive signal for blocking to our North West and a very slack jet stream.

[Geordiesnow]

Must admit, it's rather interesting and surprising the GFS has made the strong westerly flow just that bit stronger whichmay help bring the snow level down a big further. ECM is slightly less cold but with such low thicknesses and chilly air, then if the GFS is right I would not bet against wintry weather getting to quite low levels.

Either way it's an interesting week coming up with the moist tropical maritime air to start off with being replaced by clean chilly showery colder air, some areas will drop by 10C in 1 or 2 days. 

Edited November 13, 2016 by Geordiesnow

[ArHu3]

7 minutes ago, Zakos said:

Technically you are right, but the amplified pattern over the atlantic indicates a ridging in the atlantic is likely, with low heights more likely over europe.

 The deep blue/purple colours are centred over eastern siberia, indicating this is where most of the ensembles show the Core of the PV to be placed.

Yes, they do not show actual weather conditions, but I believe they indicate a definitive signal for blocking to our North West and a very slack jet stream.

If you do see something it could be a hint (like jet stream over Pacific) but if you don't see it (like the jet stream over the atlantic ) doesn't mean anything 

Edited November 13, 2016 by ArHu3

[legritter]

Yes reading between the lines using Met office update to me is another tool in our armoury ,things looking good for colder wintry synoptics ,model watching as just become very interesting ,tonights runs eagerly awaited i,m sure, catch you up later .

[bluearmy]

16 minutes ago, ArHu3 said:

If you do see something it could be a hint (like jet stream over Pacific) but if you don't see it (like the jet stream over the atlantic ) doesn't mean anything 

As far as mean jet stream is concerned on the meteociel charts, I agree. the rest of what you have said -  I don't agree with all of it. 

The mean 500 hpa charts and anomolys in conjunction with spreads is a very useful tool. 

Edited November 13, 2016 by bluearmy

[Zakos]

12 minutes ago, ArHu3 said:

If you do see something it could be a hint (like jet stream over Pacific) but if you don't see it (like the jet stream over the atlantic ) doesn't mean anything 

I think in regards to the jet stream you may well be right. However, there is still a trend for the jet stream to wane in strength throughout the duration of the runs. The height anomaly mean certainly indicates northern blocking may well begin to take hold again.