Model output discussion - 1st December onwards

[coldcomfort]

Given the GFS propensity to underdo maxima, 17c cannot be considered out of the question somewhere across the midweek period, which in December is borderline insane imo. By way of context, Newcastle failed to exceed 17c on 15 days in June, 15 in July and 5 in Aug this year, roughly 1 in 3 summer days!

 

 

 

 

 

Edited December 15, 2015 by coldcomfort

[Gavin Hannah]

For the sake of the ski slopes.. I hope the mild temps are being over cooked. 10 degrees at 8am in december is just bonkers nevermind whats being forecast.

[karyo]

2 hours ago, Ali1977 said:

Perfect, re-run of 1947 then..

1947 didn't have an exceptionally warm December and wasn't a record breaking warm year globally though...

[Nouska]

It took the GFS a while to get on the page as to MJO direction: now that it has - text book phase 4 composite charts being modelled. I assume this ridging is what is raising interest; certainly a powerful shot of warmth if it comes off like that.

      

Where it goes next and how amplified will be interesting as it is not really expected in background strong Nino - see archived charts in link.

http://ds.data.jma.go.jp/gmd/tcc/tcc/products/clisys/mjo/monitor.html

 

 

[MP-R]

GFS continuing to show a more anticyclonic outlook come Christmas onwards - not necessarily cold, at first at least, but most importantly a lot drier which would benefit areas further north and west too! Let's hope these signals continue. With time, an anticyclonic dry spell can quickly become colder at this time of year.

[johnholmes]

4 minutes ago, Nouska said:

It took the GFS a while to get on the page as to MJO direction: now that it has - text book phase 4 composite charts being modelled. I assume this ridging is what is raising interest; certainly a powerful shot of warmth if it comes off like that.

      

Where it goes next and how amplified will be interesting as it is not really expected in background strong Nino - see archived charts in link.

http://ds.data.jma.go.jp/gmd/tcc/tcc/products/clisys/mjo/monitor.html

 

 

As you say N, it will be interesting to see what evolves. Looking at the GFS one I use it shows 4 and suggests either into 5 in low orbit or disappearing into the zero area. link below Neither of which is of any comfort to cold lovers, or so it seems to me.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/foroper.shtml

[Ravelin]

I suppose there's a theme to an extent i.e heights to our East, but the GFS seems to be throwing out different scenarios in FI, and the route to them is different. Short of any real interest in the shorter term (other than potential record warmth), kind of worth keeping an eye on.

[Summer Sun]

Some exceptionally mild nights coming up this week I've know nights in summer to be cooler, the one exception looks to be parts of Scotland where the nights will be closer to average

[knocker]

18 minutes ago, johnholmes said:

As you say N, it will be interesting to see what evolves. Looking at the GFS one I use it shows 4 and suggests either into 5 in low orbit or disappearing into the zero area. link below Neither of which is of any comfort to cold lovers, or so it seems to me.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/foroper.shtml

If it's of any interest you can get a quick look ar assorted MJO forecasts

http://www.frontierweather.com/MJOGraphics/mjoanalogs.html

[Glacier Point]

36 minutes ago, johnholmes said:

As you say N, it will be interesting to see what evolves. Looking at the GFS one I use it shows 4 and suggests either into 5 in low orbit or disappearing into the zero area. link below Neither of which is of any comfort to cold lovers, or so it seems to me.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/foroper.shtml

We appear to have a major model divergence here John.

UKMO (MOGREPS) very different to the GEFS / GFS:

EC somewhere in between:

But interestingly more developed than a few days ago and keener on a phase 6-7 propagation:

The key here is not the relative magnitude but the phase space, and perhaps the final destination of the MJO signal (although the strength of the signal evolving through phase 4-5 is of importance in determining degree of amplification).

The EC demonstrates reasonable skill when MJO waves are in progress (although all show issues with tropical wave formation over the Maritime Continent). What we are seeing with this morning's EC EPS and now GFS 06z op confirms the idea that the atmosphere is about to get substantively more amplified as westerly wind tendency is introduced and fluxed poleward associated with a phase 4 evolution. In the short to medium term, that may mean we get even warmer as the Atlantic trough signal interacts with the amplification, but ultimately this is about both the tropospheric AO and stratospheric vortex.

Edited December 15, 2015 by Glacier Point

[carinthian]

2 hours ago, carinthian said:

Amazingly mild charts for this side of Christmas. Though I am more encouraged to see post Christmas Charts ( Boxing Day onwards) both shown on the latest ECM and GFS models of a significant rise of pressure over the British Isles. A developing slow moving trough in Mid Atlantic outwards the Azores should slow things down. So turning Less Mild possible rather cold and significantly much drier post Christmas. Lets hope this trend continues during todays later runs .

 C

The 06z GFS follows on from earlier indications of a general pressure rise, post Christmas. So perhaps a cooling off, I was never told to use that word in the winter season, but seems more descriptive after this weeks abnormal temps to come across much of Western Europe. But more importantly some drier weather on the cards for you lot post Boxing Day and a hint of some lower pressure values heading for the Alps, but not much in the way of much needed snowfall. Anyways, perhaps the first indications of a change to more seasonal conditions.

 C

[coldcomfort]

We are some distance from deep and crisp and even on the big day based on the 06GFS. The big fella will be sweating in his suit for sure. 

 

 

 

 

 

Edited December 15, 2015 by coldcomfort

[feb1991blizzard]

6z GEFS trending towards GP's Sceuro ridge solution.

 

Edited December 15, 2015 by feb1991blizzard

[carinthian]

Just now, feb1991blizzard said:

6z GEFS trending towards GP's Sceuro ridge solution.

Yep, I read that earlier. He has latched onto something very different. . I hope it verifies and the last 2 outputs from GFS  starting to show that development post Boxing Day.

 C

[feb1991blizzard]

3 minutes ago, carinthian said:

Yep, I read that earlier. He has latched onto something very different. . I hope it verifies and the last 2 outputs from GFS  starting to show that development post Boxing Day.

 C

In fact one member shows a full on Scandi high with a cold Easterly, that's too fast I would suggest, the strat would have to be telepathic to respond that quick!!, the ones I'm interested in are the really sharp ridges slicing through up into the polar regions like a knife through butter, these could slaughter the vortex completely.

[nick sussex]

Further to GP's post on those big MJO disagreements the latest from the BOM update which includes data from the 14th December:

Satellite imagery shows an area of enhanced cloudiness extending from the eastern Indian Ocean to the Indonesian archipelago, coincident with the passage of the Madden—Julian Oscillation (MJO) in the region.

So at least we know its definitely on the move.

Ironically things could turn even more mild initially as GP alluded to because as any troughing amplifies in the Atlantic it will push a long draw southerly into the Arctic, however this will help weaken the PV eventually. Where the energy goes from that troughing is the next issue, theres a big difference in temps for Europe if the high to the east can get further north and nw as this might help disrupt some energy from that troughing.

If we do reach phase 7 the composite anomaly with a positive ENSO:

Phase 7 would likely bring some colder drier conditions to the UK as the flow will likely move round to the se and mainland Europe temps would fall at the same time.

At this point I think the only realistic route to any cold is from high pressure to the east/ne.

 

Edited December 15, 2015 by nick sussex

[IDO]

4 minutes ago, nick sussex said:

Further to GP's post on those big MJO disagreements the latest from the BOM update which includes data from the 14th December:

Satellite imagery shows an area of enhanced cloudiness extending from the eastern Indian Ocean to the Indonesian archipelago, coincident with the passage of the Madden—Julian Oscillation (MJO) in the region.

So at least we know its definitely on the move.

Ironically things could turn even more mild as GP alluded to because as any troughing amplifies in the Atlantic it will push a long draw southerly into the Arctic, however this will help weaken the PV eventually. Where the energy goes from that troughing is the next issue, theres a big difference in temps for Europe if the high to the east can get further north and nw as this might help disrupt some energy from that troughing.

If we do reach phase 7 the composite anomaly with a positive ENSO:

Phase 7 would likely bring some colder drier conditions to the UK as the flow will likely move round to the se and mainland Europe temps would fall at the same time.

 

Hi

I always follow Dr Ventrice on these matters as he is the expert in this field:

 

[Glacier Point]

We can see this convective activity now:

NWP now seems to be dropping big hints of a high amplitude phase 4 MJO wave in the next 5-10 days, moving into the Western Pacific. Westerly winds will be introduced on the back of this and tendency in angular momentum will spike upwards.

The key issue is where we go from there ? Weakening MJO signal, +AO re-establishes itself - or - Sceuro ridge takes root and begins to inflate further north and north-west serving it up to the tropospheric AO, in turn reducing the polar westerlies and promoting momentum transport southward of 30N, further feeding westerly wind additions and further weakening of the +AO ?

[nick sussex]

2 minutes ago, IDO said:

Hi

I always follow Dr Ventrice on these matters as he is the expert in this field:

 

I read the twitter banter going on and this MJO is certainly cause for much debate. At this point not to overplay the importance but we need something to change the pattern and also weaken the PV. We're all aboard the Good Ship MJO, lets hope it doesn't hit rocks and sink!

[Newberryone]

While I pretty much agree it's all about looking for signs in Fi, I'd be very hesitant right now in giving much credence to anything outside the reliable time frame with regards to sustained pressure rises as indicated especially by the GFS. As IDO pointed out earlier, the GFS op has this tendency to  overdo  height rises when it spots another slower Atlantic period, but the mean keeps it real. Besides, any Euro ridge that may take hold post St Stephens Day/Boxing Day, looks as has been the case so far to be more beneficial to southern/southeastern UK than anything on a widespread scale.  Christmas week itself is looking very turbulent indeed, especially for flood stricken Eire.  

Edited December 15, 2015 by Newberryone

[knocker]

11 minutes ago, Glacier Point said:

We can see this convective activity now:

NWP now seems to be dropping big hints of a high amplitude phase 4 MJO wave in the next 5-10 days, moving into the Western Pacific. Westerly winds will be introduced on the back of this and tendency in angular momentum will spike upwards.

The key issue is where we go from there ? Weakening MJO signal, +AO re-establishes itself - or - Sceuro ridge takes root and begins to inflate further north and north-west serving it up to the tropospheric AO, in turn reducing the polar westerlies and promoting momentum transport southward of 30N, further feeding westerly wind additions and further weakening of the +AO ?

I can see where you are coming from GP but looking at the EC32 (broad brush version) I assume the ecm is not keen on this route.

[Gavin Hannah]

HP has definetly been shown on quite a number of the recent outputs.  It would be something akin to 2009/10 if something materialised within the 10 day timeframe. That said, I am encouraged by the info you guys are posting. Something does appear to be afoot and it may be the slither of hope we need to lift us out of the doom and gloom.

[Catacol]

55 minutes ago, Glacier Point said:

We appear to have a major model divergence here John.

UKMO (MOGREPS) very different to the GEFS / GFS:

EC somewhere in between:

But interestingly more developed than a few days ago and keener on a phase 6-7 propagation:

The key here is not the relative magnitude but the phase space, and perhaps the final destination of the MJO signal (although the strength of the signal evolving through phase 4-5 is of importance in determining degree of amplification).

The EC demonstrates reasonable skill when MJO waves are in progress (although all show issues with tropical wave formation over the Maritime Continent). What we are seeing with this morning's EC EPS and now GFS 06z op confirms the idea that the atmosphere is about to get substantively more amplified as westerly wind tendency is introduced and fluxed poleward associated with a phase 4 evolution. In the short to medium term, that may mean we get even warmer as the Atlantic trough signal interacts with the amplification, but ultimately this is about both the tropospheric AO and stratospheric vortex.

Hmm - you've just done it again Stewart. Another suggestion of something very different out beyond 30 days. My spidey sense is beginning to tell me that this winter is quite possibly going to be one of contrasts... and the second half therefore very different to the first. RJS has forecast the same. Perhaps we all need to hibernate with a few glasses of mulled wine and return to the models on January 2nd. The medium term outlook at that point may well be very different...

[Nouska]

Baby steps but it's all pointing to a more positive new year.

 

The black hole  ...                                     

ECM mean for similar time frame. ....  

 

[nick sussex]

In support of the ECM's forecast( which of course we want to verify!) the ECM has two ensemble systems, one which uses just real time data and the other which involves some climatology. Both ECM's support the quicker progression of the MJO, the CFS using climatology does aswell. The only model lukewarm about the MJO is the GEFS so we have to hope that this is wrong!