Model Output Discussion - 31/10/2014 and Beyond

[easton888]

Quick question: as in the chart above, could the vortex be split 'too wide' with the North American side sending us endless rain as the energy warms over the Atlantic?

[BLAST FROM THE PAST]

 

Whap!  F off Atlantic...you can come underneath,,,but that's it!

 

On a serious note the deep cold awaits but that's not the story, its the hemispheric pattern.  Will it lock in to be a barnstormer?  

I think there's lots to play for yet, we are still in autumn after all

 

BFTP

Edited November 9, 2014 by BLAST FROM THE PAST

[Man With Beard]

And that Knocker is a hemispheric set up that WILL lead to cold, it is average to slightly above for a little while, if maintained the switch will come

 

BFTP

General point - in my experience, it is possoble for 850s to look average when from a slack E/SE, but unless it's long fetch from the Mediterranean, or just a short SE that is mainly Atlantic sourced, even average 850s from that direction will usually lead to below average temps from mid-November onwards away from coasts. Would find examples but must sleep!

[Mark Neal.]

Quick question: as in the chart above, could the vortex be split 'too wide' with the North American side sending us endless rain as the energy warms over the Atlantic?

If the vortex locates to a similar locality( or becomes more organised chose to Greenland) to last winter you get low pressure systems coming off the eastern seaboard which traveling over the Atlantic end up as even nastier low pressure systems which blighted winter last year for us in UK with Heavy Rain.

All depends on the positioning of the Vortex ofcourse. A split vortex wouldn't necessarily herald that pattern from my understanding with less mobile Atlantic pattern or Blocking keeping the low pressure at bay. Perhaps more knowledgeable folk could correct me if wrong.

Edited November 9, 2014 by Mark N

[BLAST FROM THE PAST]

General point - in my experience, it is possoble for 850s to look average when from a slack E/SE, but unless it's long fetch from the Mediterranean, or just a short SE that is mainly Atlantic sourced, even average 850s from that direction will usually lead to below average temps from mid-November onwards away from coasts. Would find examples but must sleep!

Yep RJBW...mods u can delete, response only

 

BFTP

[Nick F]

I think some of the cautiousness that people have is that whilst that is true and somewhat remarkable at this point, Europe is still relatively mild and any weather type that comes in off the continent and not the north or north east as a result of those changes will, at the moment, not deliver the much desired snowy Synoptics. Nonetheless I entirely agree that we have to get the pattern in place first, and the pattern emerging right now is something highly unusual and surely encouraging.

True, the deep cold has a long way to come for now looking at model output, even by day 10. But encouraging signs for later this month and indeed, perhaps Dec and beyond too, with ECM and GFS both showing wave 2 over Greenland in the tropsphere (major 500mb ridge) potentialy upwelling to trigger a strat warming event to split the strat vortex which could have ramifications for the rest of the winter by shredding the polar vortex and sending lobes of deep cold air southwards from the Arctic. We are already seeing this from Canada into the US courtesy of the Nuri-induced wave 1 big ridge building event over Alaska into the arctic.

Similarly, a wave 2 over Greenland may eventually help the very cold air the other side of Svalbard flood SW towards us and much of Europe as the block over Scandi is forced to retrogress towards Greenland.

[Mark Neal.]

 

Whap!  F off Atlantic...you can come underneath,,,but that's it!

 

On a serious note the deep cold awaits but that's not the story, its the hemispheric pattern.  Will it lock in to be a barnstormer?  

I think there's lots to play for yet, we are still in autumn after all

 

BFTP

Yep it's the bigger picture which I find starkling. Get the blocks in place and then further down the line we could have a great chance. Worth looking folks at the comparison over the past few days, many model runs upgrading the chance of Vortex Split.. tomorrow will be intriguing

[ItNeverSnowsInWindsor]

Amazing 18z pub run from the GFS with stronger blocking to the North!

Looks like the 18z has been listening to the new U2 song -

Every breaking wave from Songs of Innocence!

[Mucka]

Given the ECM ensemble mean is probably better than the 12z OP, I feel that barring some big U turn ECM will show some much better charts again tomorrow. (actually today, damn  my insomnia)

This is an impressive 10 day mean chart.

 

Edited November 10, 2014 by Mucka

[shaky]

Looks like gfs parallel is finally smelling the coffee this morning!!!both the gfs are improvements on yesterday's 00z runs although fi could be better!!!ecm looks fine so far and ukmo is better than yesterday mornings run!

[kimb]

Looks like gfs parallel is finally smelling the coffee this morning!!!both the gfs are improvements on yesterday's 00z runs although fi could be better!!!ecm looks fine so far and ukmo is better than yesterday mornings run!

 

It looks to me that the models are wanting to take the High pressure to the North away later on as the Atlantic comes back.

[Polar Maritime]

The GFSP does have a go at some sort of Easterly, Before the Atlantic makes in-roads from the N/W. Still lots of uncertainty out in the runs.

 

Edited November 10, 2014 by Polar Maritime

[knocker]

Before the apocalypse really quite warm.

Courtesy WxBell

Edited November 10, 2014 by knocker

[Jimmyh]

Sorry wanted to pose a question for pm. The Atlantic making in road in fi if that chart was to come off that would be cold and wet wouldn't it as the 528 dam seems to be all over the country. I Realise the direction the arlantic us coming from but after last years awful winter I don't seem to remember the 528 being that far south

[Polar Maritime]

Sorry wanted to pose a question for pm. The Atlantic making in road in fi if that chart was to come off that would be cold and wet wouldn't it as the 528 dam seems to be all over the country. I Realise the direction the arlantic us coming from but after last years awful winter I don't seem to remember the 528 being that far south

 

Yes Jimmy, A cold and very wet Pm flow from the N/W. But im pretty sure this will change. It's just one run out of many, With such a disrupted Vortex and wave 2 warming in the stratt the Models are still very skitty at this range.

 

Edited November 10, 2014 by Polar Maritime

[Robbie Garrett]

The potential is definitely there. I suspect the models will drop the idea very soon though and bring it back, just like 2010.

I remember someone mentioning in 2010 the models struggled processing something and it defaulted to raging westerly before coming back for a synoptic dream 7 days from the event. Was it a shortwave that changed the models breifly before coming back online?

Hope someone can answer this.

[MR EXTREMES]

the gfs builds heights strong through iceland into greenland the declines heights briefly but then takes another shot.

we have an easterly but not much excitement in terms of cold and snowy, but its still very early in nov and its just good to see the hemispheric set up going in the right direction i think december will hit back with something much more exciting.

 

although as ive suggested its an easterly which is a good start.

 

the gfs para is not as good as the control as with the control we have a deeper depression bit like the mood of some in here lol.

but with the control run for the same time with have a sharper deeper low and better angle of attack to try for another shot at heights over greenland.

 

 

the ecm holds firm across iceland and you can see the deep low exiting the states bringing possibly round two of a heights build into greenland but a good run going forward.

as you can see theres a split waiting to happen then the real fun starts to take shape into jan.

the ukmo is sort of on side with the ecm!

but what is clear that the ecm was over progressive and has moved to a more middle ground but still has the potential to bring greater things into dec.

 

the anom 500z show the lucky horse shoe through the arctic and this could progress into something truely special into dec.

i dont want deep cold yet but dec jan and feb if were lucky would be fantastic.

 

but over all still a few things to be sorted into the end of nov hemispheric wise but all good.

 

jma last night was like the ecm the night before but we really need lows to push futher into europe.

[mushymanrob]

Strong block over Scandi, troughing to the SW rather than NW? Should do for most? (Though maybe not you in Cornwall )

Edit - I find anything off the continent will be fairly cold by mid-nov, so that includes SE

 

i dont.... why? because its modifed atlantic/southern scourced air thats travelled around the southern flank of the atlantic lows circulation.but of course it depends what you mean by 'fairly cold'

 

yesterday i posted that the anomaly charts dont support and easterly, well this morning they do..

 

however the 850 uppers dont suggest itll be particually cold.... yet anyway.

 

.

id welcome an easterly because it might dry up some of the rainfall we are getting!

 

[Banbury]

If we are being totally honest snow was never on the cards ......short term, it is all about building blocks .

[Polar Maritime]

If we are being totally honest snow was never on the cards ......short term, it is all about building blocks .

 

Exactly Banbury, But please lets get back to what the Models are showing.

 

Thanks, PM

[bluearmy]

If we are being totally honest snow was never on the cards ......short term, it is all about building blocks .

It was for Scotland on yesterday's ECM mean. New one out soon

[MR EXTREMES]

The other scenario would be that the block to our North sinks across the uk!.
Aiding further with lows heading into Europe to the south of us!
But maintaining a surface high but this would be chilly and seasonal with frost and fog under any clear sky's.
Over all very seasonal but different hemispheric pattern this winter.

Edited November 10, 2014 by Polar Maritime
To remove off topic references.

[Banbury]

Exactly Banbury, But please lets get back to what the Models are showing.

 

Thanks, PM

 

http://www.meteociel.fr/ukmo/runs/2014111000/UN144-21.GIF?10-06

 

Certainly UKMO seems to go the right way

Edited November 10, 2014 by Polar Maritime

[Gibby]

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY MONDAY NOVEMBER 10TH 2014.

NEXT UPDATE TUESDAY NOVEMBER 11TH 08:00

THE CURRENT GENERAL SITUATION. A strengthening Southerly flow will carry a pair of fronts East into Western and Central areas later today, tonight and tomorrow.

MODELS-2 WEEK HEADLINE  Unsettled with rain at times across the British Isles with strong winds too and temperatures near to normal. perhaps becoming a little colder and drier from the North later.

THE JET STREAM ENSEMBLE FORECAST The GFS Jet Stream Ensemble forecast shows the flow maintained in a complex form but with the main core held to a position to the South of the UK for much of the period with varying strengths from day to day.

GFS OPERATIONAL Today's GFS operational run shows the UK under bombardment from Low pressure areas crossing the Atlantic and becoming slow moving close to the West and SW of the UK with repeated spells of rain and showers affecting the UK especially the South and West with mild Southerly winds for all. Through week 2 Low pressure edges further North for a time which only serves to bring more SW winds and quicker moving troughs running East and NE over the UK with sunshine and showers in between with temperatures close to average.

THE GFS PARALLEL RUN The GFS Parallel run carries the same sequence of events throughout with the northern High pressure to the NE collapsing later with a more direct hit of Atlantic wind, rain and gales for all as a result with Low pressure allowed to cross the UK directly rather than being held up just to our West.

THE GFS ENSEMBLES.  The GFS Ensembles are rather different through Week 2 as they allow High pressure to remain and in fact build to the North later in the output with the Low pressure areas afflicting Southern Britain in particular through Week 1 weakening and allowing a colder and drier Easterly flow to develop across the UK by the end of the period.

UKMO. UKMO today shows deep Low pressure over the Atlantic steadily slipping SE towards SW England at the end of the week with rain and heavy showers continuing as a result especially across South and West Britain while the North and NE could become rather drier next weekend with much cloud and sea mist rolling into Eastern and Central parts  in the East and SE flow.

THE FAX CHARTS  The Fax Charts show a series of slow moving occluded fronts with disturbances running North along them delivering copious rainfall across Western and Central Britain over the coming 48 hrs or so before a more gentle SW and showery flow crosses the UK for a time before renewed complex troughing attached to another deep Low West of Ireland moves into the UK from the SW by next weekend.

GEM  GEM shows Low pressure in total control of the UK weather over the next week to 10 days repeatedly moving into the UK from the west while filling slowly. Rain and showers look maintained across all areas over the period with little change in temperatures values to currently and strong winds at times.

NAVGEM NAVGEM keeps Low pressure domination across the UK and as other models show having reached UK shores they stall and fill slowly with rain and showers scattered about on most days. Some chillier air is shown to infiltrate Northern regions late in the run with Low pressure then in a belt across the Atlantic the South of the UK and into Europe with the cold air in the North edging further South with time.

ECM  ECM this morning shows little respite from the current pattern of Low pressure to the west and SW of the UK with stalling fronts running into Southern and Western Britain in particular with heavy rain at times here. Northern and Eastern parts could become somewhat drier as pressure is high to the NE. Little change looks likey to this overall pattern this side of Day 10 with temperatures holding near or somewhat above normal in mostly Southerly or SE winds.

THE ECM ENSEMBLES   The ensembles point to a continuation of broadly unsettled weather with rain at times across the UK in average temperatures and a SE flow as Low pressure continues to stretch from Southern Greenland to the SW of the UK. Some of the rain will be heavy and winds look like continuing quite strong at times. Pressure remains High to the NE of the UK at that time.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend today shows a somewhat reduced chance of High pressure developing to the North and NE bringing drier conditions to the North and East in Week 2 with slightly colder weather.

MY THOUGHTS  The pattern of a Jet flow blowing further South than it's normal position continues to offer the complex mix of Low pressure just to the West of the UK feeding decelerating troughs into the UK from the West and this looks like continuing for a long while yet. This means that rain will be heavy and prolonged at times as the troughs move in, slow or stall and this looks most likely over Western, Central and SW Britain for the next week or so. Beyond that things do complicate somewhat as there is still a variety of output still having a desire to enhance High pressure to develop from the North and NE later to at least bring drier and somewhat chillier conditions to the North and NE whereas it looks unlikely that this makes it''s way down to Southern Britain as the feed of Low pressure from the Western Atlantic continues to approach the SW at times with further rain as a result. In fact the GFS operational and Parallel runs show Northern blocking colllapsing entirely later with major Atlantic storms close to the NW oof Britain as a result. The amount of output showing any cooler solution has reduced somewhat and where it is shown it is in quite a diluted form with probably NAVGEM flying the chilliest resolution for the North a week from now. The GFS Ensembles don't look bad either for cold lovers down the line with a Scandinavian High developing but cold air is held at arm's length and just outside of the run term. However, with not much support from the ECM operational and it's Ensembles who maintain a cyclonic feed from a Southerly point across the UK it looks unlikely that we will see much more than a split in the Weather in a week to 10 days with the South and West continuing to see the risk of quite large amounts of frontal rain at times from slow moving troughs while the North and East gradually see drier conditions develop with time closer to High pressure to the NE with temperatures remaining close to average overall.

[IDO]

No changes in my thoughts for November. I believe that the US will feel the cold from the HLB NH and the UK will just be a bystander. This morning's output does not change anything in relation to that. There is an odd cooler run in the GEFS but just a continued background signal. Though the GEFS after D12 do show high uncertainty within the 0z suite, so I would ignore that part of F1. Background signals re bottom up warming continues and for the UK its a case of waiting for this effect on the strat. and the subsequent downward effect. December remains of interest in this context.

 

The GEM for instance has severe cold reloading in the US with the UK in a warm sector: 

 

Though the NH profile remains promising with a 1050mb Arctic High and the vortex remaining split.

 

ECM similar in long wave pattern but with a cooler sector in our region: 

 

GFS Parallel not dissimilar, just variations in energy distribution and flow so we get middle ground temp wise compared around GEM & ECM:

 

 

 

After about D12 the GEFS show no clarity as to upper air flow (850s). That is when the meridional flow relaxes and the US cold pool gets ejected from the Conus. That upper flow will reboot the colder air and there are possibilities for the UK to tap into some of this, even if it is transient. That will resolve with further runs.