Model Output Discussion 12z 23/05/13

[Tamara]

I think the ECMWF ensemble mean is more convincing than the GEFS mean because the ridge of high pressure is brought closer in (pressure reaches or exceeds 1025mb over most of the country by T+216) and I doubt that cool cloudy weather would be widespread in eastern areas with the ridge getting that close.  This is a stark contrast from previous runs where the ECMWF mean generally had the high further west than the GEFS mean.

This has been good part of my own caution about any change in the pattern to one of a more higher pressure dominated type.. Also the METO up to now have been very cautious in terms of atlantic high pressure moving in and this is the first time, as you hint at, that the ECM and its ensembles have shown any interest at all in following up the GEFS ensembles suggestion which up to now has been wrongly signalled with the jet stream staying too amplified.  The next few days will be interesting to see if this is sustained and if so how it develops. A reverse N/S split is possible if the High moves to the north of the UK as pressure may be reluctant to rise much over the nearby continent.

Edited May 25, 2013 by Tamara Road

[Evening thunder]

Haven't seen an ensemble mean this good for settled weather for a while: 

A good sign to see at least.

 

 

With 850hpa temps around 5C maxima would probably be around 20C perhaps creeping above in one or two spots away from windward coasts or sea breezes, although the uppers would probably rise in the following days should something like the ECM mean materialise. 

A little way to go though I think with the GEM and ECM operational runs bringing a cold pool back down over us trying to form more of a trough/low near us in the process again, although they bring some more settled and slightly warmer weather before that and I think there are some good signs to be had this morning for more settled/warmer weather after most of next week.

Edited May 25, 2013 by Stormmad26

[Frosty.]

The Gfs 06z shows Bank holiday monday turning into a fine and pleasantly warm day for most of the uk with only the far west of britain being unsettled and cooler with rain at times, the front bringing the rain then fizzles out across western areas and makes no progress eastwards and by tuesday it's sunshine and scattered heavy showers with hail and thunder.

[Frosty.]

The 6z shows the unsettled spell next week downgrading towards nothing more than an annoying little showery blip before pressure rises strongly from the west by around the middle of next week which quickly reduces the shower risk, later next week the azores ridging spreads across the uk with temperatures recovering again and long sunny spells. low pressure near iceland becomes a bit of a thorn in the side for northwest britain but only for a time, generally it's a nationwide improving story through FI with the azores anticyclone taking total control with temps rising into the low 70's F but northern and eastern coastal areas would have cooling onshore breezes but you won't have to go far inland for it to become warm, with high pressure eventually becoming more centred to the west of the uk, it blocks off the route for atlantic depressions which will have been diverted well to the north of the uk by then, the polar front jet well out of harms way and most of the uk would be basking in lots of strong sunshine. not quite flaming june but a huge improvement on the awful spring so far.

Edited May 25, 2013 by Frosty039

[BornFromTheVoid]

Taken at face value, then current modelling would suggest temperatures a lot warmer than much anything we have seen since last summer but with maybe something of a NE'erly breeze some windward coasts would be kept much cooler with North Sea temperatures still in single figures for the most part. The key part of your post obviously is the 'should the above pan out' part.

 

Agree with this.While things are certainly looking more positive over the medium term, any potential warmth from the east or south will have to make it's way over waters that are close to 2C below average.

 

[049balt]

Again you have to ask where are the Met coming from re. todays update.

[Summer Sun]

Again you have to ask where are the Met coming from re. todays update.

 

TBH I wouldn't worry about them updates currently best just to keep looking at the ensembles and the models for trends the met office updates can and do change frequently

[Frosty.]

Again you have to ask where are the Met coming from re. todays update.

I wonder what mogreps is showing them, the ecm, gfs, ukmo and gem are showing them a summery spell is on the way.

[Chris K]

TBH I wouldn't worry about them updates currently best just to keep looking at the ensembles and the models for trends the met office updates can and do change frequently

Yes if the trend of a warmer settled spell continues in the models you will find their updates change soon enough.

Unless they see something we don't of course

[Frosty.]

Yes if the trend of a warmer settled spell continues in the models you will find their updates change soon enough.

Unless they see something we don't of course

At least the usual doom merchants have gone quiet..for now

 

If anything, the models have taken another big stride towards a warm and settled outlook compared to yesterday, next week now only looks briefly unsettled and then generally anticyclonic well into June.

[Milhouse]

Had a few days off after a shocker of an ECM 12z, which made me think we were heading for a dreadful start to June. I come back and things are looking a lot more positive with high pressure from the Azores making a visit towards the end of next week. At the moment it looks like it will orientate itself as so to bring average warmth rather than any notable heat but in light winds it would give most parts a nice start to Summer.

 

Temperatures not that great but a 1030mb high in June would be

 

[Milhouse]

Thursday loking a decent day too with warmish uppers over the UK.

 

 

[NeilN]

I think looking at those charts, this is VERY encouraging for Summer 2013. Today is rather warm and pleasent in the South West. If this can keep up, I will be very happy.

It doesn't have to be 35c but this spell will make A LOT of people happy.

[Tamara]

Yes if the trend of a warmer settled spell continues in the models you will find their updates change soon enough.

Unless they see something we don't of course

Its not a popular thing to say I know, but putting aside the face value suggestions of height anomalies from ECM and GFS this morning which look good, if one reads between the lines then I think it can be understood why the updates are not reflecting the expectations of settled weather. The longer term NAEFS anomalies suggest a retrogressing pattern with the higher anomalies moving towards southern Greenland and perhaps west of there and we are left in an area of perhaps flat pressure which would continue to support a showery regime at this time of year. Temperatures higher in the North and West *for a time* as the update states, would be supported by the presence of high pressure closest to there after this weeks trough departs, until perhaps the higher anomalies back further west as indicated by the spreads.

[Barry12]

The Met Office were suggesting a good start to June in their further outlooks before when the models were showing more unsettled weather. Now the models are suggesting high pressure bringing settled conditions their saying the opposite.

[Purga]

Again you have to ask where are the Met coming from re. todays update.

Probably from the updated ECM 32 dayer, which is not to be sniffed at.

 

'Little change is expected as we head through the first week of June, with temperatures remaining rather cool, but locally warm in some northern and western parts, at least for a time.

Updated: 1144 on Sat 25 May 2013'

 

Seems like the signal for higher pressure to the NW of the UK and S jet track again favoured. Cooling down in the NW thereafter as well & surely looks on track for another below average CET this month, not to everyone's taste but a remarkable run of cold / cool temps for the last 5 months.

 

The ENS 06z looking flatter with cool conditions around the start of June ( notable grouping). Also precipitation amounts look to be higher.

Although the warming trend is still there in FI the Op & Control runs split with the latter going for cool conditions

 

Pretty hard to call really so some may be lucky and some not but no heatwave.

 

 

 

 

No real prolonged warm dry spell but quite a few pleasant days to be had no doubt.

Edited May 25, 2013 by Purga

[Chris K]

Its not a popular thing to say I know, but putting aside the face value suggestions of height anomalies from ECM and GFS this morning which look good, if one reads between the lines then I think it can be understood why the updates are not reflecting the expectations of settled weather. The longer term NAEFS anomalies suggest a retrogressing pattern with the higher anomalies moving towards southern Greenland and perhaps west of there and we are left in an area of perhaps flat pressure which would continue to support a showery regime at this time of year. Temperatures higher in the North and West *for a time* as the update states, would be supported by the presence of high pressure closest to there after this weeks trough departs, until perhaps the higher anomalies back further west as indicated by the spreads.

Very fair analysis from you and others. It will be a case of what the operational models show as we progress through next week I think.

Its a constant tense waiting game model watching! I've always stuck with 'look no further than 4-5 days' but its always interesting to read peoples thoughts on likely trends further on.

Edited May 25, 2013 by Chris K

[Evening thunder]

Its not a popular thing to say I know, but putting aside the face value suggestions of height anomalies from ECM and GFS this morning which look good, if one reads between the lines then I think it can be understood why the updates are not reflecting the expectations of settled weather. The longer term NAEFS anomalies suggest a retrogressing pattern with the higher anomalies moving towards southern Greenland and perhaps west of there and we are left in an area of perhaps flat pressure which would continue to support a showery regime at this time of year. Temperatures higher in the North and West *for a time* as the update states, would be supported by the presence of high pressure closest to there after this weeks trough departs, until perhaps the higher anomalies back further west as indicated by the spreads.

 

Interesting, although that appears to be from yesterdays 00z runs, be interesting to see what todays show and if it still shows the same trend. 

[Methuselah]

Its not a popular thing to say I know, but putting aside the face value suggestions of height anomalies from ECM and GFS this morning which look good, if one reads between the lines then I think it can be understood why the updates are not reflecting the expectations of settled weather. The longer term NAEFS anomalies suggest a retrogressing pattern with the higher anomalies moving towards southern Greenland and perhaps west of there and we are left in an area of perhaps flat pressure which would continue to support a showery regime at this time of year. Temperatures higher in the North and West *for a time* as the update states, would be supported by the presence of high pressure closest to there after this weeks trough departs, until perhaps the higher anomalies back further west as indicated by the spreads.

Good points there, Tamara...But the one difference from last year (IMO) is that the pressure gradient doesn't look like being as extreme, this time??? And, if it were not for the exceptionally cold SSTs in the North Sea and English Channel, such an outlook mightn't be all that bad? This year though, I amn't quite so sure...

[Frosty.]

The Met Office were suggesting a good start to June in their further outlooks before when the models were showing more unsettled weather. Now the models are suggesting high pressure bringing settled conditions their saying the opposite.

M  O  G  R  E  P  S

 

I thought the ecm 00z ensemble mean would have meant something to the met office, it looks so good.

[Tamara]

Good points there, Tamara...But the one difference from last year (IMO) is that the pressure gradient doesn't look like being as extreme, this time??? And, if it were not for the exceptionally cold SSTs in the North Sea and English Channel, such an outlook mightn't be all that bad? This year though, I amn't quite so sure...

The actual pattern sure looks different at face value to last year, at this stage. But I think we need to see how it evolves. If the pattern does retrogress then that will simply spill upper cold pools south once again and that is not going to be an ingredient for dry weather as the difference between intense seasonal surface warming and the upper air triggers instability. The height anomalies on those NAEFS anomalies suggest a northerly type of vector to the airstream, so temperatures would likely to be kept restricted - assuming this is how the modelling plays out

 

 

Todays NAEFS update I assume follows later Its also true to say that NAEFS can be wrong. along with other ensemble modelling. But we need to look at what data there is available, to try and get as complete a picture as we can. Not every chart in isolation tells us everything we need to know

Edited May 25, 2013 by Tamara Road

[049balt]

Good points from Tamara today which brings good balance to the discussion.

[Frosty.]

M  O  G  R  E  P  S

 

I thought the ecm 00z ensemble mean would have meant something to the met office, it looks so good.

The more I think about it, the more surprised I am that we are apparently not looking at a warm and settled outlook, both the Ecm 12z ens mean last night and the 00z this morning are showing solid support for the Azores anticyclone ridging northeast with a trend towards very warm and sunny weather for all of the uk for most of the first ½ of June.

[Methuselah]

The actual pattern sure looks different at face value to last year, at this stage. But I think we need to see how it evolves. If the pattern does retrogress then that will simply spill upper cold pools south once again and that is not going to be an ingredient for dry weather as the difference between intense seasonal surface warming and the upper air triggers instability. The height anomalies on those NAEFS anomalies suggest a northerly type of vector to the airstream, so temperatures would likely to be kept restricted - assuming this is how the modelling plays out

 

 

Todays NAEFS update I assume follows later

I recall 1968 (?): in MK we had a succession of LPs to our SE that resulted in repeated thunderstorms, daytime darkness and generally cloudy, cool and humid weather...and something like that seems a possibility this year? But - and it's a big one - I can't recall any of the days, back then, when nothing much happened!

 

No doubt, my reading of the models is being influenced by my love of humid, thundery weather...As you say, though, we need to see how the situation evolves. 

[Frosty.]

 

No doubt, my reading of the models is being influenced by my love of humid, thundery weather...As you say, though, we need to see how the situation evolves. 

How I would love a spanish plume, however, we definately won't get one of those for a while if high pressure builds strongly to the northwest of the uk, we would need high pressure to migrate to the east and low pressure to push into Biscay and then we would be in business.

Edited May 25, 2013 by Frosty039