Model Output Discussion

[grab my graupel]

Please continue to discuss the Models

All the latest Model output and lots of other useful information can be viewed in the Netweather Datacentre:

http://www.netweather.tv/index.cgi?action=charts;type=home;sess=

Brian

[mushymanrob]

...24 hours after i viewed charts and nothing has changed. theres still a huge block over greenland and a weak southerly tracking jet on this mornings models. i enjoyed my two days of heat, but it may transpire that that was it.

[Gibby]

A little quiet on the model front this morning as this changeable weather continues.

UKMO shows a steady rise of pressure through the rest of this week as high pressure down to the SW takes hold. NW winds with a few showers likely tomorrow before progressively brighter and warmer conditions reach all parts by Saturday. Over the weekend the High pressure cell drifts into the North Sea, pressure falls with the chance of rain or showers for many come Sunday.

GFS looks much the same while from Sunday the charts look quite changeable and always pulling frontal systems in from the west, most active in the North with occasional ridges in the south giving the best of any drier and brighter spells with temperatures for the most part near normal though occasionally warmer in the south.

ECM also lowers pressure from the North over the weekend with a distinctly unsettled and showery back three or four days to its run.

Across the three models this morning it looks like after a dry interlude late this week and at the start of the weekend the weather will be dominated by Low pressure to the North, High pressure near the Azores and Greenland. There would be periods of rain or showers for the North and at times in the south too though some bright and occasionally warm interludes will be mixed in here.

[shedhead]

I think any conclusions drawn from interpretation of the overnight runs very much depends on whether you are a glass half full, or glass half empty person. Those on the half full side of things would

point to the fact short/medium term prospects are not bad at all, with a good deal of dry, sunny weather on offer for many, and as winds fall light later in the week it should start to feel pleasantly warm.

Those on the half empty side however will point to this week being a brief (albeit welcome) respite in what is an essentially unsettled and disappointing outlook, with the Greenland block remaining

unseasonally robust and the Jetstream too far south to allow any genuine nationwide heat as we enter July. Whatever side of the full or empty side anyone sits though I think it's worth considering

(much as when looking for protracted bitter, snowy spells in winter) that we perhaps expect to much of our weather here in the UK. It's always worth remembering we are an island, surrounded by

relatively cold sea in the summer and relatively warm sea in the winter, which clearly has a significant moderating effect on our weather/climate. In general it's much more difficult for us to do

extremes, so whilst many of us love them and crave them, we should perhaps leant to lower our expectation levels and try to enjoy the weather we do get. It maybe difficult for some to accept this

fact and to be honest I understand why, but having lived in one of the hottest parts of the world for many years I can assure you there are many millions of people that would give their right arm

for our gentle, forgiving climate - we are actually very lucky in the grand scheme of things.

Edited June 28, 2011 by shedhead

[Iceberg]

I started of by looking at my area and thought there must be some kind of north south divide.

For me in Dorset I have a week or so of warm dry weather, very little if any rain and temps between 18-21C so rather nice really as I am closer to the high pressure nudging in.

This is backed up by the ECM, GFS ops as well as the EPS and ENS member averages.

The SE might get a few more showers over the next 48 hrs but it looks predominantly dry here from then onwards for at least the next week.

However even for places further NW such as Chesire,(see ENS below) it looks dry to me, fresh but again rather nice.

IT's only really as we try to look out into FI that the trends start to diverge, again there are some signs of more unsettled weather, but by and large end ENS averages 1015 or above for Dorset and the precip ENS charts for selected places across the UK are not indicative of anything more than scatter IMO.

So a good week coming up, obviously not hot, particularly when compared to the 32/33 recently and then some uncertainty as we go further out than a week.

Edited June 28, 2011 by Iceberg

[Downpour]

I think any conclusions drawn from interpretation of the overnight runs very much depends on whether you are a glass half full, or glass half empty person. Those on the half full side of things would

point to the fact short/medium term prospects are not bad at all, with a good deal of dry, sunny weather on offer for many, and as winds fall light later in the week it should start to feel pleasantly warm.

Those on the half empty side however will point to this week being a brief (albeit welcome) respite in what is an essentially unsettled and disappointing outlook, with the Greenland block remaining

unseasonally robust and the Jetstream too far south to allow any genuine nationwide heat as we enter July. Whatever side of the full or empty side anyone sits though I think it's worth considering

(much as when looking for protracted bitter, snowy spells in winter) that we perhaps expect to much of our weather here in the UK. It's always worth remembering we are an island, surrounded by

relatively cold sea in the summer and relatively warm sea in the winter, which clearly has a significant moderating effect on our weather/climate. In general it's much more difficult for us to do

extremes, so whilst many of us love them and crave them, we should perhaps leant to lower our expectation levels and try to enjoy the weather we do get. It maybe difficult for some to accept this

fact and to be honest I understand why, but having lived in one of the hottest parts of the world for many years I can assure you there are many millions of people that would give their right arm

for our gentle, forgiving climate - we are actually very lucky in the grand scheme of things.

Great post. We have a brilliant climate here, particularly in the benign SE. Personally, while I love the sunshine, yesterday's heat is unpleasant for working and commuting in. Here's to a fortnight of 22c days with sunny spells and the odd shower – lovely. Oh to be in England in the summertime.

[conor123]

Potentially a really awful setup returning by next Monday, luckily until then bar the odd shower its not looking to bad.

This weekend still has the potential to be glorious for England & Wales at least.

Today's 'sunshine' hasn't materialised though so thats another day of Summer gone...

Edited June 28, 2011 by conor123

[ohno]

Plenty of sunshine here in Westyorkshire... Not a bad summers day.The central and southern part of the country is under a weather front..

[shedhead]

Potentially a really awful setup returning by next Monday, luckily until then bar the odd shower its not looking to bad.

This weekend still has the potential to be glorious for England & Wales at least.

Today's 'sunshine' hasn't materialised though so thats another day of Summer gone...

Certainly a decent 2nd half of the week in prospect for most of us, but I suspect we'll see the Atlantic breakdown speeding up a little on subsequent runs (as is often the case), so not sure we can assume a glorious weekend

even for England and Wales. That said any rain should be light and patchy for the most part, but there will probably be to much cloud for many people's liking, except perhaps in the extreme east.

[Thundery wintry showers]

The outlook for this coming weekend has changed on the GFS since yesterday with the front holding off until Sunday, so Saturday is progged to be a bright, fairly warm day with a scattering of showers, and Sunday's front also looks pretty showery in nature. Yesterday's charts suggested a mostly dry cloudy weekend but today's suggest rather brighter weather. Thus, I think it's fair to say that cloud amounts for the weekend are open to serious question.

Still looks like there will be a fair number of showers around on Wednesday and Thursday, especially in E Scotland and NE England where there is a moderate chance of weak thunderstorms, before the ridge of high pressure kills off most of the showers for Friday. The absence of frontal activity continues to suggest that sunshine amounts will probably be quite high even in the showery northeast.

The pattern into FI reminds me of July 1998 with low pressure centred over Scandinavia and high pressure staying firmly out to the SW and Atlantic systems crossing the country at intervals, but is of course subject to change at this sort of range. However, I think it is quite a likely possibility as long-range signals, and the Met Office monthly updates, have consistently suggested that we could evolve into a similar type of July, relatively dry in the south but with large amounts of cloud everywhere.

[johnholmes]

For the next 10-15 days nothing is apparent that would change the overall wavelength weather pattern. Most models at this range favour an upper low/trough near/NW of the UK allowing a fairly strong upper flow from a mainly westerly point into the UK. Its strength does suggest that any warmth/dryness away from the SE will be a passing feature only. Its would seem unlikely that the 2 day heat/humidity now clearing most of the SE will be repeated in the time scale mentioned, 10-15 days. Links further out also eem to suggest to me fairly good support for this idea.

[Alex]

For the next 10-15 days nothing is apparent that would change the overall wavelength weather pattern. Most models at this range favour an upper low/trough near/NW of the UK allowing a fairly strong upper flow from a mainly westerly point into the UK. Its strength does suggest that any warmth/dryness away from the SE will be a passing feature only. Its would seem unlikely that the 2 day heat/humidity now clearing most of the SE will be repeated in the time scale mentioned, 10-15 days. Links further out also eem to suggest to me fairly good support for this idea.

Hi John,

Where do you think meto get the idea of a more sustained very warm dry spell of weather which is described in the 16-30 day outlook, I can't see Many signs of this however as GP said yesterday a mix of mjo phase 1 & 8 could see a repeat of the recent scenario.

[EaasmanG]

I have taken a look at the various models and concluded that if you want summer in July you will not see much like it this first half. I do think that temperatures will return to average by the second half after we have this north wind all first half and some very cold nights.

[Glacier Point]

Hi John,

Where do you think meto get the idea of a more sustained very warm dry spell of weather which is described in the 16-30 day outlook, I can't see Many signs of this however as GP said yesterday a mix of mjo phase 1 & 8 could see a repeat of the recent scenario.

Comparison of GFS and UKMO MJO forecasts gives some insight as to why the 15-30 dayer is getting the necessary amplication in the sub-tropical ridge (Azores ridge):

Clearly some differences here in the extended range forecast period which are unlikely to be satisfactorily resolved through the use of ensembles for the time being. The interesting point to note is that both now agree on a phase 8/1 destination, the critical differences being timing and amplitude.

Edited June 28, 2011 by Glacier Point

[johnholmes]

Hello Alex re your post.

I was predicting only out to 15 days and as you post their later outlook is for 16-30 days.

Perhaps the answer to some extent is in what GP (Stewart) posted below that question. But as he posts it’s a far from ‘done’ thing yet. They both, GFS/Met for MJO predict into an 8/1 phase as Stewart shows but which will be correct? I have no idea and accept that GP is far more knowledgeable than I in trying to predict at this time scale.

I do find the MJO and even further out predictions are, like shorter term synoptic outlooks, are just that, predictions. Sometimes they are correct and other times they are not. Would that any of us were clever enough to be able to decide when they are giving the correct advice and when not.

I think its pretty certain what type of weather pattern we are going to have out to about day 15, beyond that to me it looks uncertain. But remember I’ve happily acknowledged that my expertise at such time scales is far from the best!

john

ps

phase 8 for July suggests high pressure in the uk area, 1 suggests the opposite and across the eastern half of the Atlantic, or that is how it looks to me!

Edited June 28, 2011 by johnholmes

[Alex]

Comparison of GFS and UKMO MJO forecasts gives some insight as to why the 15-30 dayer is getting the necessary amplication in the sub-tropical ridge (Azores ridge):

Clearly some differences here in the extended range forecast period which are unlikely to be satisfactorily resolved through the use of ensembles for the time being. The interesting point to note is that both now agree on a phase 8/1 destination, the critical differences being timing and amplitude.

Thanks Stewart and John, very useful. Out of the 8 phases what would we need for a sustained July 2006 type spell, im aware its extremely unlikely we will get anything like this but in terms of a sustained hot spell in the summer is a phase 8 amplification the best to hope for? Thanks

[johnholmes]

Thanks Stewart and John, very useful. Out of the 8 phases what would we need for a sustained July 2006 type spell, im aware its extremely unlikely we will get anything like this but in terms of a sustained hot spell in the summer is a phase 8 amplification the best to hope for? Thanks

over th GP for that

re the 16-30 outlook Met isued, and have done since their last update based on their interpretation of the ECMWF T+600 and something I think?

their quote is

There is also a chance that we may see a more prolonged dry and very warm spell as we go through July, most likely in the south of the UK.

Note it says chance and most likely in the south of the UK.

[Glacier Point]

Thanks Stewart and John, very useful. Out of the 8 phases what would we need for a sustained July 2006 type spell, im aware its extremely unlikely we will get anything like this but in terms of a sustained hot spell in the summer is a phase 8 amplification the best to hope for? Thanks

.. a combined, and strong signal from both the MJO and GWO for a phase 7/8 evolution although a strong phase 8/1 signal would be good enough to amplify the sub-tropical ridge sufficiently for the south to benefit.

[Thundery wintry showers]

Interesting stuff- so a strong implication here that the models are currently placing the centre of low pressure too far east past T+144, and confining high pressure too strongly to the Azores. It'll be interesting to see whether the models back down from the pattern they are currently showing, and if so when.

[Ben_Cambs]

To me the UKMO 12z run today portrays a rather weak Atlantic with the main Atlantic trough stuck way out west (T+144) but GFS places it much closer to the UK, the centre to the South of Iceland.

UKMO T+144 http://www.wetterzentrale.de/pics/Rukm1441.gif

GFS T+144 http://www.wetterzentrale.de/pics/Rtavn1441.png

As a result, showers would break quite frequently across Northern and Western areas with longer spells of rain possible. UKMO would paint a drier picture though scattered showers couldn't be ruled out. It would be cooler than average in the North and West, with temperatures closer to average the further South and East. GFS is a disappointing run for those in the NW of the UK especially due to the reluctant trough, some longer spells of rain would occur it would feel quite cool and some showers may break out widely if GFS verifies.

[Gibby]

Well done you folks in the SE today. Heat storms aren't something that feature on the models much tonight.

UKMO shows the next few days with a slightly showery west to northwest flow with pressure building from the SW to form High pressure over us by the Weekend. This continues moving NE out into the North Sea as a cold front approaches the west late Sunday as pressure falls. Several dry and reasonably warm days are likely, especially in the south before the shower risk increases Sunday.

GFS shows a similar pressure rise over the next few days before showing the high slipping east rather quicker than UKMO meaning Atlantic fronts and accompanying showery conditions reach most parts over the latter part of the weekend. From then on GFS paints an unsettled and showery spell with some more prolonged rain at times, temperatures not much better than normal and just brief drier spells.

ECM keeps the high pressure theme going for the end of the week with the same fall of pressure through the weekend allowing the risk of showers to increase with time. Further on and ECM takes a very unsettled turn with fairly deep Low pressure close to the North influencing the UK with cool and very showery conditions and more prolonged rain at times with no sign of an end anytime soon after the 240hr chart.

Things look decidedly changeable still from tonight's output with rain and showers for all from time to time with the Atlantic train in total control across the three models. No doubt some places in the south and southeast may fair better than elsewhere but with the charts as shown there would be no gaurantee for any sustained dry spell even here.

[bluearmy]

despite the ecm throwing out the odd optimistic fi run, the upper trough has had our name on it for next week for a while now. the best we can hope is that its influence is less evident the further south you are compared to earlier in june. to follow ? not sure really but not happy to see the mean atlantic jet consistent and continue to point at the south of the uk through fi naefs.

[rob48]

Really enjoyable read on this latest model thread.

Certainly improved by the absence of cherry-picked FI scenarios at six-hourly intervals.

[Backtrack]

Never seen this thread so dead.

Either people are too upset to discuss the terrible summer output, or are busy in the Spanish Plume thread.

[Thundery wintry showers]

It's not a "terrible" output at all, except for those who expect the UK to be part of the Mediterranean. Realistically speaking, perhaps disappointing for some and acceptable for others.

Low pressure and fronts continue to be delayed for over the weekend so a bright, fairly warm Saturday with a scattering of showers, and Sunday may well be bright too with a scattering of showers, though I think Sunday will probably have more cloud overall. Wednesday-Friday continue to look bright, showery to begin with (especially in the NE where scattered weak thunderstorms are possible) and showers largely fading away by Friday due to the advancing ridge of high pressure.

It continues to look dodgy for warmth/sun/dryness out into FI with low pressure transferring towards Scandinavia, but teleconnections outputs suggest that the models may be being too progressive here, as noted in some earlier posts which favoured the main trough staying to the NW.