Model Output Discussion - 31/10/2014 and Beyond

[SLEETY]

well eastern europe could be going in to the freezer if 18gfs is correct............

[Geordiesnow]

Wheres this mild air everyone's talking about?

 

 

To be fair the mild air is over us at the moment but there is nothing what you would call significantly mild in the output and with a strongish easterly wind about to develop, it certainly won't feel mild. 

 

Would be nice too see a true cool airmass soon which has been lacking this autumn. 

[summer blizzard]

Paralell sticks the finger up at the Atlantic, barely a front would pass through alive.

 

Chilly away from the south too.

 

[Polar Continental]

Interesting developments in The later stages of the 00:00z GFS, now trending towards a much colder scenario as the big Russian high extend its influence ever further westward and at the same time an Atlantic low is forced under the block helping push much colder uppers toward eastern area of the British Isles.

http://www.wetterzentrale.de/pics/Rtavn3121.gif

[knocker]

Paralell sticks the finger up at the Atlantic, barely a front would pass through alive.

 

Chilly away from the south too.

 

 

Yes it's been running with variations of this for three runs and this morning introduces a SW ridge and a shallow trough.

 

Courtesy WxBell

[kimb]

Well no sign of anything cold but I think the GFS especially the 'para' has backed away from bringing the wet and windy stuff in ! 

[knocker]

Some significant changes with the GEFFs anomalies this morning compared to 12z yesterday.

 

At t168 the Canadian low,trough is constrained to running N/S instead of extending into the Atlantic and the Scandinavian HP reinforced and blocking the jet. This gives rise to Surface HP from the central Atlantic eastwards.

 

At T240 similar picture with the trough running N/S central Atlantic with HP in the east. Also a ridge along the eastern seaboard so surface HP cells both east and west.

 

This may well be a transient situation as there are signs that this will not be a durable block down the line but hey, that's speculation.

 

Temps above average.

 

Charts courtesy WxBell

 

Edited November 15, 2014 by knocker

[mushymanrob]

Wheres this mild air everyone's talking about?

 

 

here

here

 

here

here

 

the point being that anyone can cherry pick a chart or two to prove a point, and i must say to my eye the gfsp 's evolution looks plausible, and the noaa anomaly doesnt rule it out

 

 

but in reality thats only one possible option. cases can be made for a mild outlook as much as a cold one. i wont pretend to understand the more technical data, so i listen to the pro's who do. and several, both senior forecasters on here and on the tv mention itll be mild at least at times. if anybody doesnt agree, take it up with them, not me!

[Jason M]

Looking through the individual GEFS this morning there are some decent runs in there if it's cold your after. Taking 300 hours as the comparison point (yes it's a long way out) there are some cold runs.

As this time point takes us closer to the end of the month there are more runs with decent cold pools associated. As always nothing is certain, But there is just a hint of a signal in the modelling upto 300 hours in my view so I certainly wouldn't be betting the house on the Atlantic this morning.

After high res ends on GFS I only really treat FI as just another ensemble member tbh

Jason

[bluearmy]

With the trend for a scandi high , there will be cold members on the ens as we see on the ops that small depressions will get through the gap where the sceuro ridge meets the arctic high (ne of Greenland). These will run around the block and deliver cold pools into Europe that get caught in the flow. The parallel being a case in point today.

However, will there be a scandi high or just a re strengthened sceuro ridge with the jet going over the top towards Svalbard? I'd say 50/50 on that at the moment although the models under estimation of the Russian ridge's strength is clear over the past 48 hours. Looking at where the modelling currently is, de bilt could look a lot colder than here under a gentle se flow. They could be sourcing dry air from Eastern Europe whilst ours is from the med. either way, even without cold here, for the time of year, I'd be happy with a strong sceuro or decent scandi (or even scrussian) block looking ahead mid dec onwards.

[Captain Shortwave]

Well Barry95 is still right about "Where's the mild"

The models are starting to suggest an absolute ripper of a southerly. Sometimes you just have to laugh. Given the ECM has a moderate southerly flow for a few straight days, we could be seeing temperatures reaching near record values for the time of the year.

Add to that that Euro/Scandi block is being seen as being at least a temporary feature across all the models (Day 5/6). Though only the ECM has it parked for the extra few days whilst the GFS/GEM break the block down and produce an area of heights more UK centred.

That said, the UKMO also looks like throwing the kitchen sink (warmth wise at us too)

Edited November 15, 2014 by Captain shortwave

[Great Plum]

Well, look at the spread on the GFS ensembles for London...

A big spread after 21st - up to 20c difference in upper air temps...

http://www.wetterzentrale.de/pics/MT8_London_ens.png

It's good to see some proper cold runs appearing - but equally mild ones as well!

Interesting times!

[knocker]

Warmth. Oh the old ECM

 

[bluearmy]

Just to re iterate that you won't get cold to the mid latitudes (us) unless you get warmth to the high latitudes. Europe and the eastern pacific seem to be a good source for that warmth over the past few weeks (re Aleutian trough/scandi ridge) and going forward. it's got to be somewhere and better it's us now than in winter proper ? without the warmth headed north (and associated waves), you would likely be looking at a stronger strat vortex and a worse outlook for winter cold spells.

We should all be happy to lose battles in November and win the war come jan/feb. The other way around probably leads to a cold spring - ugh! However, the current set up isn't really losing a battle - we're just laying out our troop formation so that when the time comes to strike, it can be over quickly.

I guess the search for a cold start to winter is down to the appalling excuse of last year - understandable but winter lasts for three months and proper cold never does. patience required.

[Gibby]

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY SATURDAY NOVEMBER 15TH 2014.

NEXT UPDATE SUNDAY NOVEMBER 16TH 08:00

THE CURRENT GENERAL SITUATION  .A slack Low pressure lies to the South and west of the UK with light cyclonic airflow across the UK persisting. A slow moving trough remains slow moving over NE Scotland.

MODELS-2 WEEK HEADLINE  Remaining largely unsettled with rain at times, especially in the NW while Southern and Eastern parts become drier and mild at times

THE JET STREAM ENSEMBLE FORECAST The GFS Jet Stream Ensemble forecast shows a very variable pattern over the coming two weeks with a split in the flow developing. One arm is then shown to cross east at high latitudes north of the UK while anorther arm lies to the South. Both arms of the flow interject at times from a ridging and troughing pattern and bows quite strong at times.

GFS OPERATIONAL The GFS operational this morning shows the general shift of synoptics to change from low pressure to the South and West of Britain over the next week to more like Low pressure to the North and West with a slow shift of rain emphasis moving more towards the North and West by next weekend in slack winds generally. In Week 2 High pressure crosses the UK with a fine dry and possibly foggy period before Low pressure returns down over the UK from the Atantic with outbreaks of rain and showers for all once more in near to average temperatures.

THE GFS PARALLEL RUN The GFS Parallel run shows an earlier influence of High pressure from the East and South through next week with dry and fine weatehr arriving from midweek with mist and fog patches at night and patchy frost too in mild South or SE flow by day. Through the second half of the run the pattern of High to the East and SE collapses as Low pressure moves in from the West bringing a return to wet and windy weather in average temperartures to end the run.

THE GFS ENSEMBLES.  The GFS Ensembles show High pressure from the East influential to the UK from midweek for the rest of the run, suitably positioned at first to ptomote dry and fine weather from soon after midweek with a mild Southerly flow. Through Week 2 the orientation of the High to the East changes to allow firstly colder air to spread west over the UK and unsettled weather from low pressure to arrive at the end of the period with cold rain and wind moving up from the South then.

UKMO. UKMO today shows Low pressure to the SW midweek with a band of rain and fresh breezes on Wednesday giving way to benign and dry conditions later in the week as the Low fills leaving a slack SE flow and rather cloudy but dry conditions across the UK in average temperatures.

THE FAX CHARTS  The Fax Charts show a complex structure of filling Low pressure ambling around the UK over the next 72 hours or so before a simplified pattern develops towards midweek as a more defined trough crosses the UK slowly from the West. The weather remains largely unsettled with rain or showers at times through the period in relatively light winds and average temperatures.

GEM  GEM also shows a similar pattern to the rest next week with High pressure to the SE maintaining largely relatively mild conditions with the shift of influence from Atlantic fronts gradually becoming more focused towards Northern and Western Britain while the South and East see less rain and some drier interludes in between.

NAVGEM NAVGEM shows relatyively mild conditions too next week with occasional rain from weakening troughs before it shows a High pressure ridge developing over the South from the SW next weekend.

ECM  ECM this morning shows pressure building steadily next week as with the other models the shift of the Atlantic influence moves more towards the North and West from midweek. Pressure will then become quite high from a belt stretching from the Azores to Europe with a long fetch SW flow developing over the UK and much of Northern Europe keeping any threat of cold air a long way from the UK and keeping relatively dry and benign conditions over the South and East of the UK with time.

THE ECM ENSEMBLES   Not issued at time of publication of this report.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend continues to grow towards rising pressure to the East and South of the UK with the rain and wind influence becoming most prolific to the North and West of the UK rather than elsewhere.

MY THOUGHTS   The models are now settling on a theme of keeping cold away from the UK as rising pressure to the South and East of the UK becomes dominant from soon after the middle of the coming week. While this news will not be welcome to those looking for something cold and wintry it will be very good news for those saturated areas that lie across western britain currently as it looks as though once we move out of the midweek period there will be much less rainfall for those areas affected and this will allow at least a window of opportunity for some drainage of river courses etc. As indicated earlier it doesn't look like becoming cold and frosty under this high pressure influence as the positioning of it is likely todraw some mild air North across the UK for a time and later a mild and cloudy SW flow seems more than likely. Though fog could become a problem if any clear skies prevail overnight frost will remain patchy at worst as cloud and upper air temperatures remain above average. There is a chance that the Atlantic influence will return to all areas late in the period as the High to the East or South collapses but at this range I wouldn't bank on it happening in any shown way this morning. So in a nutshell there seems little sign of Autumn 2014 going out on a cold note and the season once more will end up being a very mild and at times wet one with frosts rather less than average and day and night temperatures as a whole over the three months being well above average at times.

[Cloud 10]

Looking through the individual GEFS this morning there are some decent runs in there if it's cold your after. Taking 300 hours as the comparison point (yes it's a long way out) there are some cold runs.

As this time point takes us closer to the end of the month there are more runs with decent cold pools associated. As always nothing is certain, But there is just a hint of a signal in the modelling upto 300 hours in my view so I certainly wouldn't be betting the house on the Atlantic this morning.

After high res ends on GFS I only really treat FI as just another ensemble member tbh

Jason

 

Yes,some decent northerlies amongst those ensembles this morning which were distinctly lacking last winter.

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-3-1-360.png?0

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-5-1-288.png?0

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-17-1-360.png?0

 

 

Moscow ensemble watch re-initiated.

 

[TSNWK]

Yes,some decent northerlies amongst those ensembles this morning which were distinctly lacking last winter.

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-3-1-360.png?0

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-5-1-288.png?0

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-17-1-360.png?0

 

 

Moscow ensemble watch re-initiated.

 

MT8_Moskau_ens.png

Yes,some decent northerlies amongst those ensembles this morning which were distinctly lacking last winter.

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-3-1-360.png?0

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-5-1-288.png?0

 

http://modeles.meteociel.fr/modeles/gens/run/gensnh-17-1-360.png?0

 

 

Moscow ensemble watch re-initiated.

 

MT8_Moskau_ens.png

I will have a number 3 if I may.. Nothing wrong with a little bit of eye candy on a Saturday morning and already we are seeing a little more interest than the whole of last winter.

[IDO]

Just to re iterate that you won't get cold to the mid latitudes (us) unless you get warmth to the high latitudes. Europe and the eastern pacific seem to be a good source for that warmth over the past few weeks (re Aleutian trough/scandi ridge) and going forward. it's got to be somewhere and better it's us now than in winter proper ? without the warmth headed north (and associated waves), you would likely be looking at a stronger strat vortex and a worse outlook for winter cold spells.

We should all be happy to lose battles in November and win the war come jan/feb. The other way around probably leads to a cold spring - ugh! However, the current set up isn't really losing a battle - we're just laying out our troop formation so that when the time comes to strike, it can be over quickly.

I guess the search for a cold start to winter is down to the appalling excuse of last year - understandable but winter lasts for three months and proper cold never does. patience required.

 

 

Yes totally agree. I have been saying for days that the cold pattern on this amplified spell has passed us by. Now we just have to take the medicine and hope this repeating pattern of Azores ridging to Scandi continues. Unfortunately the Atlantic-Greenland ridge looking unlikely from the current PV daughter lobes. So we will get some smashing mild charts:

 

 

 

With the Atlantic flow hitting the block, slowing and disrupting, the jets position will determine where the wetter weather is. The GFS solution is the tidiest with the Atlantic going over the top of the Azores/ScEuro block till late in FI where some split energy undercuts. The control is what is possible if all the boxes are ticked:

 

 

Though again 3-4 weeks down the line this would be preferable. So from the 12z's the trend for the Atlantic to be more SW to NE with heights over the UK continues. Good consensus on the London GEFS for 6-7 days of pressure around 1020mb from Wednesday next week:

 

 

After that anybodies guess.

Edited November 15, 2014 by i'm dreaming of...

[beng]

With the trend for a scandi high , there will be cold members on the ens as we see on the ops that small depressions will get through the gap where the sceuro ridge meets the arctic high (ne of Greenland). These will run around the block and deliver cold pools into Europe that get caught in the flow. The parallel being a case in point today.

However, will there be a scandi high or just a re strengthened sceuro ridge with the jet going over the top towards Svalbard? I'd say 50/50 on that at the moment although the models under estimation of the Russian ridge's strength is clear over the past 48 hours. Looking at where the modelling currently is, de bilt could look a lot colder than here under a gentle se flow. They could be sourcing dry air from Eastern Europe whilst ours is from the med. either way, even without cold here, for the time of year, I'd be happy with a strong sceuro or decent scandi (or even scrussian) block looking ahead mid dec onwards.

Perhaps, with the split vortex it will be less favourable to the strong jet going over the top of the block. My thinking is if we had a solid well formed vortex then we'd see the jet less prone to splits. With that vortex segment where it is now though, it ought to send lows spinning NE, just glancing the block (perhaps with a small amount of energy going underneath), rather than powering over the top. That in itself may help build the block further with the WAA that will result. If the vortex segment comes too far west, then no doubt the block will be under more pressure.

Would be nice to at least get a decent high nearby even if it's only to dry out the air. I can't take much more of this damp crud! :-)

[wolvesfan]

Morning all,
 
My knowledge is limited compared to the majority on here.I cant see any cold whilst we have high pressure as such over Europe though,sceuro highs seem give nothing but mild for the uk we need some lower heights digging in.Heres a chart  I hope doesn't verify,

It will help with the strat vortex over Siberia only if it destroys it totally and dosnt relocate it closer to us.

I'd sooner see warmth over the states because that lobe over the Baffin island area looks a lot less intense to me.Surely the Siberian vortex is better where it is?.

[Polar Maritime]

The GFSP shows pretty average temps if not mild at times especially in the South throughout most of the run, With bands of rain/showers spreading in from the West. It's only into the last few frames where something cooler is shown, With hints of blocking to the N/E of the UK, So "maybe" something more wintry as we enter Winter proper at Months end.

 

Edited November 15, 2014 by Polar Maritime

[Yarmy]

Cohen has a new blog entry regarding the coming weeks:

 

https://www.aer.com/science-research/climate-weather/arctic-oscillation

Summary

• With the Arctic Oscillation (AO) firmly entrenched in negative territory together with strong ridging north of Alaska, colder than average conditions over the Central and Eastern US are very likely for next week. Warmer than average weather is expected over much of Europe, as the North Atlantic Oscillation remains close to neutral.
• The negative state of the AO will persist into the third week of November, with a possible return to neutral or even positive conditions before a possible swing back to negative AO conditions at the end of the month and/or early December.
• Confidence in an average negative AO state for the upcoming winter remains high given the rapid advance of Eurasian snow cover in October. This would favor a colder than average winter for much of the Central and Eastern US as well as Europe and East Asia.  The atmospheric response to snow cover so far is mostly consistent with high snow cover.
• Other climate factors such as El Niño continue to evolve but with little change over prior discussions or on how they may impact the winter forecast.

[bluearmy]

heres a great way of seeing the direction of travel on the ecm ens two weeks away.

 

two charts showing the probability of SLP > 1030mb.

 

todays 00z                                                yesterdays 12z

 

                         

 

 

 

 

one can see the movement west of the russian high. it may change in twelve hours. note the complete lack of any chance of a strong block directly to our north due to the likely direction of the northern split/or main jet towards svaalbard.

[BLAST FROM THE PAST]

With the trend for a scandi high , there will be cold members on the ens as we see on the ops that small depressions will get through the gap where the sceuro ridge meets the arctic high (ne of Greenland). These will run around the block and deliver cold pools into Europe that get caught in the flow. The parallel being a case in point today.

However, will there be a scandi high or just a re strengthened sceuro ridge with the jet going over the top towards Svalbard? I'd say 50/50 on that at the moment although the models under estimation of the Russian ridge's strength is clear over the past 48 hours. Looking at where the modelling currently is, de bilt could look a lot colder than here under a gentle se flow. They could be sourcing dry air from Eastern Europe whilst ours is from the med. either way, even without cold here, for the time of year, I'd be happy with a strong sceuro or decent scandi (or even scrussian) block looking ahead mid dec onwards.

BA...Scrussian???   That's gold.

Models really showing why a run or two cannot be 'relied' on.  That block to our east is far more robust than models gave credit for in recent days. 

 

BFTP

[Weathizard]

One thing is for sure looking at things this morning - the Atlantic isn't going to come barrelling through, the ensembles have totally switched in remarkable fashion to a much drier pattern and the Atlantic simply has no chance of coming through that sort of blocking.

GEFS for London shows very low rain totals for the coming 2 weeks, a little more for the SW but some dry weather would be lovely given the saturation we've had recently.

Take that Atlantic