Model Output Discussion 12z 10/05/13

[DR(S)NO]

Midweek onwards looks to show some quite warm overnight temperatures.

Will these be accompanied be some decent "sitting out" conditions,I wonder?

[ANYWEATHER]

Even the outer reaches of the Ecm show no warmth whatsoever! At this time scale it can be treated with a big load of salt. At the moment in my opinion ,looking for warm settled summer like conditions is like "looking for gold at the end of the rainbow"!

[mountain shadow]

Desperately poor outlook for a warm settled spell, the odd brief couple of days of drier weather here and there, but the outlook remains unsettled.

[Gibby]

Good evening. Here is the report of the 12 noon output from GFS, UKMO, GEM, NAVGEM and ECM for today Tuesday May 14th 2013.

All models show a small but intense depression near SW England transferring NE overnight. Heavy rainfall in association with this will also move NE clearing from the SW later in the night but accompanied by a short spell of gale force NW winds. Further North the weather will be altogether quieter with clear intervals and a cold night with some showers near Western coasts. Tomorrow, Thursday and Friday all share showery days once the remaining overnight rain clears the East tomorrow evening. The showers will be heavy with hail and thunder in places but some pleasant sunny spells too with temperatures still on the cold side of average.

GFS then shows the weekend with a very deep and inclement Low near NE England on Saturday swirling SW then South over the weekend maintaining wet and cold conditions for all before the new week sees the isobars open out as the low moves away to the South with sunny spells and scattered showers returning into the new week. Through FI tonight the operational tries desperately hard to settle the weather down with the large Atlantic anticyclone pushing a ridge towards the UK at times. However, it never quite succeeds through the period keeping the risk of at least some further showery activity in a light North or NW flow with further more widespread unsettled conditions drifting in from the NW to end the run.

The GFS Ensembles show a surge of uppers to above average, especially in the North with more variation developing later in the run here. In the South the trend upwards to more average levels are maintained with showers the order of the weather throughout after the heavier rainfall at the weekend.

The Jet Stream shows the UK trough now formed, lasting for a few days before the flow breaks up with a Northern arm though weak extending across the Atlantic towards Iceland by the middle of next week with a weak flow continuing well South over North Africa.

UKMO shows a weekend with Low pressure centred to the South and East of the UK with a slack North flow over Britain. Embedded troughs would deliver spells of thundery rain mixed with some sunny intervals and thundery showers. In any sunny spells that develop between the outbreaks of rain it would begin to feel reasonably warm.

GEM shows an inclement weekend too as deep Low pressure moves West to Southern Britain with copious rain and cool winds for most over the UK. next week shows the NW as the place to be as pressure builds sufficiently enough to bring some fine and dry weather with sunny spells. However Low pressure is more reluctant to leave the South next week maintaining sunny intervals and thundery showers in near average temperatures in a moderate NE breeze.

NAVGEM tonight also shows a similar evolution with Low pressure eventually moving South of the UK with it's attendant showers protracted to Southern areas whereas the North sees the best of the dry and bright weather on offer. One consolation though temperatures would be on the rise everywhere though.

ECM tonight is very half-hearted in bringing improvements into the UK next week following this coming weekend's very unsettled weather. It, a little like GFS shows some weak ridging into the UK from the Atlantic High but it fails to achieve any major inroads maintaining a somewhat showery NW airflow with further showers in places. Towards the end of the run the Atlantic High recedes further, with renewed low pressure energy sinking down from the NW to bring yet another spell of unsettled weather with rain at times and Atlantic winds.

In Summary tonight there is still little sign of any significant fine and settled weather in the coming two weeks. All the models show variations on a theme of Atlantic High pressure unable to make sufficient inroads against an unstable pool of air over or near the UK to replace the rather showery theme we have become accustomed to. To make matters worse the upbeat GEM and recent runs of other models pointing towards better conditions have been watered down tonight with further showers or outbreaks of rain likely for all in the continuing disappointing end to Spring.

[Frosty.]

A generally more unsettled and cooler Ecm 12z operational run compared to the warmer Gfs 12z but even the ecm brings an improvement after the weekend with an atlantic ridge toppling southeast with a day or so of fine and warmer weather before it starts to turn unsettled and cooler by midweek as another low slides southeast on a nw/se aligned jet, then the pattern flattens out a little and pressure tries to recover in the far south but with the generally nw/se jet persisting, there is more low pressure heading southeast, this ecm run has a back to square one feel about it and is as disappointing as the 12z last night, or more so, however, even the ecm gets it wrong sometimes so let's hope this is a rank outlier when it comes to the bigger picture with the ensembles.

[Evening thunder]

Midweek onwards looks to show some quite warm overnight temperatures.image.jpgimage.jpgimage.jpgimage.jpgimage.jpg

Will these be accompanied be some decent "sitting out" conditions,I wonder?

 

I think that's probably the max temps in the 12 hours from 12pm 12am, or possibly 6 hours from 6pm to 12am

 

If we get a relatively slack northerly with not too much cloud cover/frontal activity and decent uppers like the GFS 12Z we could get a warmish day or 2, haven't seen these temps progged on the GFS in the high res time frame for a little while:

 

 

 

 

The ECM also shows a day or two like this possibly:

 

 

However it looks quite likely that it won't last too long with cooler air possibly coming down from the north or NW again afterwards:

The GFS operational at least does hold on to warmer uppers if not completely settled weather for longer.

[Purga]

Even the outer reaches of the Ecm show no warmth whatsoever! At this time scale it can be treated with a big load of salt. At the moment in my opinion ,looking for warm settled summer like conditions is like "looking for gold at the end of the rainbow"!

Agreed.

There's no sign either in the GFS ENS

 

By and large any 'warmth' will be accompanied by rain whilst drier spells will be cool especially at night.

Edited May 14, 2013 by Purga

[Evening thunder]

Agreed.

There's no sign either in the GFS ENS

 

By and large any 'warmth' will be accompanied by rain whilst drier spells will be cool especially at night.

Seems a spell of above average ensemble mean temps there, at least as much as there is cooler than average means? nothing too warm (i.e mid 20's) but feeling warm in any sunshine probably.

 

Also only a few or definitely less than half of the ensembles are showing rain at any one time there, they could be the cooler runs but they don't look too wet (often seen much wetter) with quite a few ensembles also showing no rain on many days there.

 

Anyway I don't think the ECM ensembles are as favouable for warmer weather with a cooler 850hpa temps (though not as low as now) at day 10 with possibly a more northerly flow and an average low centre somewhere near us.

Edited May 14, 2013 by Stormmad26

[Stu_London]

18z takes Saturday's deluge much further north than the last couple of GFS runs.

 

Anyone know what the other models are showing ?

 

I'd quite like to get my game of cricket in on Saturday , before I head off to join the lads stormchasing on Sunday.

[summer blizzard]

The GFS18z operations is a very interesting run to me and one with hidden gems. Firstly we get a low on Sunday from the east which is weird in itself but weirder still is that it introduces and leaves behind warmer air, in any sunshine from Monday we could be looking not far 20C. Afterward we essentially see a similar picture with warm upper air but the high to the west ridging over the UK which keeps things dry and fairly warm all week...

 

[William of Walworth]

18z takes Saturday's deluge much further north than the last couple of GFS runs.

 

Anyone know what the other models are showing ?

 

I'd quite like to get my game of cricket in on Saturday , before I head off to join the lads stormchasing on Sunday.

It's all about exactly far North Saturday's deluge goes for me, I'll be in the East Midlands! Struggling with positioning detail ATM.

[IDO]

Agreed.

There's no sign either in the GFS ENS

 

By and large any 'warmth' will be accompanied by rain whilst drier spells will be cool especially at night.

Hi. I don't know what you expect, this is the UK! The GEFS from the 18z:

This is the Aberdeen uppers and it shows the 18z mean above the May average by 5c most of the run and even though the mean falls in FI it still stays above the average! If this temperature differential was translated to the Summer months then we would have a very nice summer.

Getting a December 10 winter again may not happen for a long time and a month of hot UK weather just doesn't happen often either. As long as we dont get a washout similar to last year, and there is nothing suggesting that synoptic at the moment, the current pattern of warm then cooler interludes seems fine.

This morning's GFS is a case in point, a cool few days followed by a warmer flow, dry days for most with bands of heavy rain hitting parts of the country now and then:

Sunday: Monday:

Tuesday: Wednesday:

HP migrating SW-NE from D7-D13: ...a continued modeled evolution.

Late in FI we drag in even warmer continental air:

Plenty of relative warmth showing here.

[mushymanrob]

Even the outer reaches of the Ecm show no warmth whatsoever! At this time scale it can be treated with a big load of salt. At the moment in my opinion ,looking for warm settled summer like conditions is like "looking for gold at the end of the rainbow"!

 

yep its what im expecting... ( )

 

its been pretty dry (for most areas) for some time now, and now its started raining i dont expect it to be a short affair.

 

ok, this is 'mumbo jumbo' , unscientific, but after years of weather watching you can get an (inexact) idea of what might happen, what previous patterns lead on to.

 

i simply dont think this current wet spell is all there is, as i see it the patterns changed, and i dont expect a prolonged settled spell anytime soon. next weeks ridging looks like breaking down rapidly and the models show this.

 

hope im wrong, sometimes i am, and sometimes not, and im not 'flipping a coin', its just a hunch based on previous observations.

[Gibby]

Hi everyone. Here is the morning look at the midnight output from GFS, UKMO, GEM, NAVGEM and ECM for today Wednesday May 14th 2013.

All models continue the unsettled theme for the rest of the week with Low pressure never far away from the UK. With cool uppers over the UK for a few more days temperatures will be suppressed by day and more notably by night with a grass frost likely in places for the next few nights. Over the weekend the uppers will warm somewhat from the East but the weather remains disturbed with further rain or showers at times into next week.

GFS then takes us through next week with a NW/SE split developing. With High pressure out to the West of Scotland with dry and bright weather developing in these NW areas next week. Further South and East a NE flow will maintain somewhat chillier weather with occasional showers. Changes through FI today are slow but involve the sinking SE of the High cell to the NW before taking it back North again in distant FI. The net result would be that the dry weather in the NW would become more extensive over the UK for a time before low pressure moves back up towards Southern Britain with a return to showery rain and cooler weather in an Easterly breeze.

The GFS Ensembles today show uppers rising strongly over the North towards the weekend and less so in the South before the pattern reflects a steady fall of uppers towards average levels in the second week though with plenty of options between the members. There is rain shown scattered about throughout the output indicative that the warmer uppers may not necessarily be translated to the surface with cloud and rain suppressing any sustained warmth from sunshine.

The Jet Stream shows the UK trough setting up over the next few days before the Jet Stream breaks up into a weak cyclonic flow South of the UK. Later the flow splits into a weak northern arm moving NE to the North of the UK and the weak cyclonic system to the South centred on an Eastward moving flow over North Africa in a week's time.

UKMO this morning takes us well into next week with the whole of NW Europe covered in shallow Low pressure meaning a continuation of the unstable pattern with thundery showers at times but some bright and dry spells too with some pleasantly warm May sunshine between the showers.

GEM too this morning keeps the UK in a locked pattern with shallow Low pressure sitting comfortably over Southern Britain early next week setting up shot to the East of the UK later in the week. The resultant Northerly feed would maintain a cool feel with sunshine and showers the likely weather type with any meaningful High pressure held well West of the UK.

NAVGEM maintains a shallow Low pressure areas close to Southern Britain and Northern France next week with the best of the dry and sunny weather in the NW while Southern and eastern Britain would remain in a more showery theme with shorter dry and bright spells in between. near average temperatures look likely next week which is an improvement on this week.

ECM finally shows a showery first half to next week before a North/South split develops towards the end of the week as a ridge from the Azores High ridges towards Southern Britain.The problem is with Low pressure moving East towards Iceland pulling Westerly winds across the North with Atlantic fronts in tow bringing rain Eastwards towards the end of the month.

In Summary the weather remains in showery mode with the UK stuck under a trough for the next week at least and possibly longer. ECM does offer something of an olive branch later as a ridge building towards Southern Britain offers some respite late next week. The problem is it is likely to be shoved away South with time as the Low to the North and attendant fronts move steadily SE beyond day 10. The rather cool conditions though should slowly lose their grip by this weekend as warmer uppers aloft should rise temperatures to near average levels generally and perhaps slightly above should any prolonged sunny spells occur next week.

[Frosty.]

The good news on the 00z runs is it looks like becoming warm for a while next week, the Gfs 00z shows a spell of warm and fairly sunny weather for the first half of next week once the few remaining showers die out in central and southern areas, temperatures rising into the low 70's quite widely across the uk with tuesday set to be the warmest day nationwide. Thereafter the gfs shows the atlantic/azores anticyclone pushing north and east to the north west of the uk and this drags cooler air down from the north/northeast so whilst it stays generally fine. it becomes much cooler but eventually there are rewards for this transitional period as the large high eventually builds directly over the uk and it becomes warmer again, eventually high pressure drifts to the north and we pick up a warm easterly continental flow with temperatures approaching the 70's once again, however, with lower pressure to the south, there would be a risk of importing a few heavy showers across southern england from france.

 

The Ecm 00z also shows a warm up by early next week but the big difference between the ecm and gfs is the ecm remains dominated by low pressure to the east with sunshine and heavy showers but warm, then it becomes cooler by midweek as the low moves further east and allows a cool nwly flow to push southeast but still with sunshine and showers, the atlantic/azores high remains well to the west for most of the run, however, towards the end of the ecm run, the azores high ridges northeast with the prospect of a warmer and sunnier trend for southern britain towards T+240 hours.

 

 

The GEFS 00z mean is like a hybrid of the gfs and ecm 00z op runs with a mix of drier and more unsettled but warmer weather for next week with variable pressure between 1010 and 1020mb.

 

There is some very mixed output this morning, the GEM 00z ends up very cool and unsettled with northerly winds with high pressure building north in the atlantic and a scandi trough.

 

 

[049balt]

Looking good.

 

http://wxmaps.org/pix/prec4.html

 

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gfs&MODELLTYP=1&BASE=-&VAR=prec&HH=180&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

[johnholmes]

Looking at the last 48 hour outputs from the anomaly charts and they are far from helpful. Unusual but there is usually a short spell as the northern hemisphere goes from winter to summer mode where this happens. This year, thanks probably to the very cold March, it is happening later than usual.

The main 3 have all altered quite markedly in the last 2-3 outputs and not altered consistently. Shifting from one idea to another. ECMWF this morning is nearer to the NOAA output last evening but both have changed both ways from trough to ridge to trough as the main feature. GFS has kept its idea from yesterday of ridging over/close by western UK with an upper low south or ESE of it over western europe, see below. This is a change though from what it had been showing.

Overall then I would not even attempt for 2-3 days to use them as a guide as to how the upper air pattern may be towards the end of May.

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

On a closer time scale it was encouraging to see my rainfall total not that wide of the most often shown figure for here, 18-25mm. Total was 17.2mm, no doubt others in this area where nearer the top end.

Edited May 15, 2013 by johnholmes

[Nick F]

Been a while since I've posted in here, but can't help but notice the differences in the modelling in the short to medium term, ECM looks like reverting to cool/cold type again next week after a brief 'warm' up this weekend, with a dominant trough/low just east of the UK next week pulling in a cool northerly flow. GFS has a much more anticyclonic flow with the dominant trough near Iberia, which means a warmer picture early next week - highs of 21-22C across southern parts on Tuesday.

The morning models are disagreeing as early as Saturday over the persistent rain moving in form the near continent on Saturday, 00z GFS has it moving across southern/central England and Wales, ECMWF has it moving across northern England, Scotland and N Ireland.

Unsual synoptics too, the low bringing the rain on Saturday is shown on ECM to come out of Nern Germany, then across the N Sea, southern Scotland before swinging southwest then south across Ireland, The Bay of Biscay then Iberia! Though we have seen similar during the past cold season.

Certainly hope GFS 00z op comes off with its warm up early next week, the cold, wet and generally miserable weather of late is becoming more than unwelcome for me after a cold spring so far.

Edited May 15, 2013 by Nick F

[offerman]

John, This does seem a continous of the uncertainties at short notice we experienced during the winter months.

[Radiating Dendrite]

The 6z has moved the precipitation for Saturday north again, more in line with the ECM.

I am praying that this is the correct evolution - if the rain band tracks across south England then my day out at Lord's will be a complete washout!

[johnholmes]

John, This does seem a continous of the uncertainties at short notice we experienced during the winter months.

not really, or not in my view I should say.

There will be times, in any season, when there are shall we call them 'wobbles', but generally the anomaly charts are relatively free from this feature unlike the synoptic outputs. What occurred in the winter, and there was one well documented one, was overall a pretty good prediction rate. The one I refer to was the subject of a post by me and in fact the changes on these charts, had I paid closer attention to them, did give an indication of the pattern change that prevented another cold extension.

What occurs pretty much every spring is a spell of a week or so, sometimes longer, when they really are not much use for predicting the upper air pattern 6-15 days or so ahead. My view, others may disagree, is that this is due to the change over of the northern hemisphere from winter to summer. Perhaps this is tied in with the changes we see in the Stratosphere but I am only suggesting this, I have no proof. There is another smaller blip in the autumn, not always, which is again I think linked to the northern hemisphere changing from summer to winter mode. I have searched around the web, even asked in R Met Soc, if anyone has done any investigation into these events but I have not had any luck finding anything so far.

hope that helps explain what I feel is the difference you comment on.

[Frosty.]

I like the way the Gfs 06z trends with the azores anticyclone building strongly northwards up to iceland and toppling southeast across northwestern britain next week, for the first time this spring, the northwest of the BI could be in for a fine and warmer spell, there is still some rain and showers around for central britain on this run but to the north and south it looks fine and warmer,  High pressure dominates this run through FI but with the high further west it means we have a cooler flow coming down from the north or northeast but with predominantly dry conditions with some sunshine. So this run is similar to the 00z but becoming less warm in FI and completely different to the unsettled ecm 00z op run and ens mean, the big difference is how bullish the gfs builds the azores high northeastwards to the west and northwest of the BI and the reluctance of the ecm to do likewise. The Gfs 00z was better but I would still take this run over the ecm/gem solutions.

 

[Buzzit]

A useful read http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

I am thinking we are going to be heading towards El Nino rather than La Nina (while staying in neutral range during summer)

Edited May 15, 2013 by Buzzit

[Frosty.]

The latest met office update appears to be broadly supportive of the more unsettled and cooler side of average ecm 00z solution instead of the rather warmer & more settled gfs 00z-06z. Next week would therefore be dominated by low pressure to the east/ne with little or no azores/atlantic ridge influence although the west of the uk would be drier and brighter than central and eastern areas. The Ecm 00z ensemble mean is also painting a more unsettled picture with showers and longer spells of rain due to low pressure being in overall control and high pressure remaining well to the west of the BI, apart from some weak atlantic ridging eventually making inroads into the southwest of the uk,  the ecm is very much keeping the uk locked in a predominantly unsettled pattern for the next few weeks.

Edited May 15, 2013 by Frosty039

[summer blizzard]

Not bad again....