Model Output Discussion

[lukemc]

What makes you think the others are correct? For a while the UKMO was the odd one out with Tuesday, other models were forecasting an absolute scorcher in the SE on Tuesday, but it turned out the UKMO was right the whole time.

Maybe the UKMO seems to be the more accurate model at the moment - and remember we are talking about the GFS 06z run which seems to be among one of the less accurate GFS runs. What I do want to see is a July which is better than June I am not asking for much more than that but I do not want so see a southerly tracking jet make a return as I think we have had enough of that in recent weeks. Even though it might be correct I think it is a bit naive to automatically assume that the worst case scenario is the right one!

Does anyone think that there is a chance that we could get a similar July to 1990 with a hot July following quite a poor June? Does anyone thing the Azores High could ridge far east enough to make it possible. As I said I would be happy with a better July than June but it would be great to get a July like 1990, 1991, 1955 or even 1999 even though the latter was followed by a mediocre August.

Luke

Edited June 26, 2011 by lukemc

[Eugene]

http://www.wetterzentrale.de/pics/MT8_Manchester_ens.png

Very dry theme, a continuation of June for central areas.

[Eugene]

Well i hope GFS 12Z has overplayed the LP's systems in FI, good chance it has.

A nice ridge of HP later in the week before all that, should be nice and warm by day but with some cool ish nights, pretty low 850's and light winds give a chance of local rural ground frosts if skies are clear.

[Cecil Hogmanay Melchett]

Not to keen on 12z gfs as the conveyor belt keeps coming up with annoying lows and any high is going to be transient against that jet.

THE question is when is the jet going to calm down a bit becasue i think we have seen enough evidence to suggest the azores high is willing to ridge towards us,the trouble is its just getting pushed away.

hopefully its wrong but ukmo is also sugessting a big push from the vile atlantic.

[SP1986]

Well i hope GFS 12Z has overplayed the LP's systems in FI, good chance it has.

A nice ridge of HP later in the week before all that, should be nice and warm by day but with some cool ish nights, pretty low 850's and light winds give a chance of local rural ground frosts if skies are clear.

Given the all time lowest temperature in July is -2C I'd be doubting rural ground frost anywhere. It would have to be an exceptional event.

[TonyH]

Would not say june has been very dry for central areas. Most of the midlands close to average around 2 inches in fact.

[casparjack]

Given the all time lowest temperature in July is -2C I'd be doubting rural ground frost anywhere. It would have to be an exceptional event.

Yes, at this time of year even if the air temperature does drop below 5c, which isn't that rare in prone 'frost hollows', you are less likely to see the ground/grass temperature demonstrate much of a difference to the air temperature at screen level, because of the heat retained in the soil. For example my 30cm soil temperatures are now around 16c, it is therefore almost unknown apart from on the sandiest of soils to see a ground frost from mid June to the end of August.

[Evening thunder]

Not at all keen on the GFS ensembles I have to say, keeping the mean below average for the entire run after Tuesday:

http://www.wetterzen..._London_ens.png

ECM coming out and falling into line with the worst option if you are looking for warmth/summery weather again (there's a surprise).

And it looks like either weak patchy weather fronts or below average temperatures in between again! (how boring IMO, at least deeper lows would be more interesting)

I notice another very warm/hot spell is being shown for the models for Scandinavia again.

Every time this big fat Greenland high is shown to break down it doesn't happen or gets pushed back. Will it ever disappear this summer?

The outlook may not turn out too bad for 'not to wet' weather, with sunshine in the clearances/PM air, just after 5 years without one I need a very warm/hot (poss thundery) summery spell (only reached 22C this weekend here).

Edited June 26, 2011 by Stormmad26

[Gibby]

The 12zs tonight in a nutshell.

UKMO shows cooler weather spreading from the west across all areas in the next 24hrs with rising pressure from the SW giving several dry and bright weather days for most before cooler more showery conditions slowly extend to most areas from off the Atlantic by Saturday.

GFS shows cooler fresher crossing all of Britain in the next 48hrs. Pressure then builds from the SW to give several dry and reasonably warm weather more especially for the south. Then for the remainder of the run pressure falls steadily with spells of rain or showers for all periodically but not without some short, more settled weather in the south at times.

ECM is much like the others through the week with cooler and more showery conditions extending over the UK over next weekend as winds turn Northwesterly. It then keeps the changeable theme going with a shower or rain risk for all till the end of the run.

The extended runs from GFS and ECM show that the weather will predominate as changeable from late this week on as both models show a strong Atlantic influence near our shores between low pressure to the north and high pressure near the Azores. Some brief brighter/warmer days are shown in association with ridges crossing the south at times.

[damianslaw]

Not to keen on 12z gfs as the conveyor belt keeps coming up with annoying lows and any high is going to be transient against that jet.

THE question is when is the jet going to calm down a bit becasue i think we have seen enough evidence to suggest the azores high is willing to ridge towards us,the trouble is its just getting pushed away.

hopefully its wrong but ukmo is also sugessting a big push from the vile atlantic.

The jet traditionally stirs into action at this time of year after its spring - early summer slumber... what we really want is a northerly tracking jet and there is no sign of that occuring for the foreseeable future. We may see it tentatively moving north from time to time but not enough to bring a prolonged settled spell. Now is a very pivotal time in the summer - patterns established now can and often do set the scene for the remainder of the summer... perhaps best not to expect too much from the remainder of the summer - certainly no signs of shades of 76!

[Eugene]

Could start to feel quite sultry again by next weekend looking at some of the runs tonight like ECM, JMA, GEM after some cool 850's we pick up some warmer air from the south, pressure could build even more strongly next weekend than current models are showing.

[Backtrack]

I really would like to hear from Glacier Point.... He seems to be sleeping at the moment but he is without a doubt the best forecaster on here, and I wouldn't mind hearing his thoughts on July.

To me, it looks terrible!

[bluearmy]

I really would like to hear from Glacier Point.... He seems to be sleeping at the moment but he is without a doubt the best forecaster on here, and I wouldn't mind hearing his thoughts on July.

To me, it looks terrible!

he posted early yesterday. said that although most of the telecons pointed to the upper trough in our part of nw europe week after next, the longer range modelling was dropping heights south of greenland. uncertainty reigns.

[Uncle_Barty]

MJO forecasts are mixed - many suggesting a move into Phase 1 (not good news from the July composites - a continuation of the pattern that has persisted for much of this month) but one or two edging towards phase 8 which suggests something a lot better for summer prospects (+ve height anomalies over UK and Scandinavia), so it seems that it's all up for grabs.

I am taking any model output beyond the end of the week with a warehouse of salt.

[Cheese Rice]

Whoa! Monday is turning into a real scorcher for the majority of the country, 30.c now forecast for Leeds. Its interesting to see how we can see small upgrades that lead to quite a big difference temperature wise.

[Jason T]

Phew.... Scorchio day today. No real sleep last night and woke up with bloody bites on me. Anyway a fresher approach on the way and dry ,but before we get there we have just got a lovely piece of convectivity to enjoy, late afternoon and on through the night. Still all to play for though through july and august.

Enjoy your day all DONT get burned.

[Gordon]

Phew.... Scorchio day today. No real sleep last night and woke up with bloody bites on me. Anyway a fresher approach on the way and dry ,but before we get there we have just got a lovely piece of convectivity to enjoy, late afternoon and on through the night. Still all to play for though through july and august.

Enjoy your day all DONT get burned.

Yep fresher weather should be with me within 12-18 hours just some showers to get through this afternoon and clearing this evening

As the met office latest forecast indicates fine and hot/very hot weather weather in Eastern England , cooler cloudier with occasional rain in the north west and as for the rest of the country warm but becoming cloudier with some showers this afternoon these possibly becoming heavy and then thundery showers spreading into SE England this evening and possibly becoming frequent through the night but dry for me by then and somewhat cooler

which is a relief as this is just a little too hot for me

Edited June 27, 2011 by Gordon

[mushymanrob]

The jet traditionally stirs into action at this time of year after its spring - early summer slumber... what we really want is a northerly tracking jet and there is no sign of that occuring for the foreseeable future. We may see it tentatively moving north from time to time but not enough to bring a prolonged settled spell. Now is a very pivotal time in the summer - patterns established now can and often do set the scene for the remainder of the summer... perhaps best not to expect too much from the remainder of the summer - certainly no signs of shades of 76!

exactly! so make the most of today because it might well be the last hot day of the year... as patterns stand, its back to what weve had since early may after today. whilst theres plenty of time yet for something to change... ie the loss of the huge northern block centred over greenland, theres no tangible sign of that actually happening.

yesterday was glorious, today might match it... i want MORE! lol

[Alex]

Everyone seems rather negative but I fail to see much precipitation on the ensembles apart from tomorrow for London. Temperatures look like being around average according to the GFS.

[Glacier Point]

For those of you inerested in more heat, nothing concrete yet, but there has been a trend over the last couple of days to firstly develop a coherent tropical wave, and secondly for this to develop in the far western Indian Ocean or eastern Africa (MJO phase 8/1). UKMO ensembles and some ECM products going this way. GFS suites having non of it, although some suggestion of a weak move towards to phase 8 at the extended range.

A phase 8 convective wave would translate to a ridge over Europe and pressure falling in the Atlantic.

Can't tell you whether this is likely to happen or not - a case of watching the ensembles over the next couple of days.

[Roger J Smith]

Index values for my research show a peak in temperatures in late July also, and I've mentioned in summer outlook the possibility of a scorcher for a few days around the last week of July. I think it would flatten out to near normal in August but quite often a late July hot spell lasts into the first week of August. I would agree there's nothing too warm showing after today's heat ends, through mid-July, although Thursday and Friday look pleasant enough in the south, 22-24 C possible in places.

[Gibby]

While the excitement of today's events unfold here's a quick look at the 00zs today.

UKMO continues to show a Northwest flow through midweek with a build of pressure from the SW to be followed by falling pressure in association with an Atlantic Low out to the NW. Fine and reasonably warm weather in the south at least later in the week will give way to the risk of showers over the weekend.

GFS follows the same route with the evolution after the weekend keeping the Atlantic 100% in control with Low pressure following one another east towards the UK. High pressure will be close to the south and southeast at times so some drier and warmer spells there.

ECM also shows a ridge of high pressure being squeezed out over the weekend as Low pressure, albeit rather slack take control of the weather from the weekend. Its run is slightly less progressive than GFS but nonetheless the Atlantic rules pushing showery Low pressure in a generally westerly flow towards us from time to time.

In Summary today may be the last time we see high temperatures for a while as the models all show a westerly element to the winds from tomorrow on through the next week or two with rain at times and some drier interludes too, chiefly in the south as weak ridges pass over.

[johnholmes]

I was not able to see any charts other than one day between Tuesday and Saturday in the 500mb anomaly charts but that showed that the 3 outputs had backed away from any lengthy 500mb flow from the SW. The upper ridge to the east/SE and upper trough to the west.

The last couple of outputs have reverted back to the idea of some +ve heights showing in the Azores region rather than Europe and an upper low, on the ECMWF version, south of Iceland. GFS has this as a flatter flow into the upper low over the Baltic area. Both would suggest a rather changeable type of pattern persisting into the first possibly second week of July with only a 1 possibly at most 2 day spell when the upper flow backs to south of west, as per currently.

So I seem to be suggesting similar to Stewart (GP). Not too unexpected as he is using drivers that in turn impact on the 500mb anomaly charts.

Or indeed Gibby above who is using the operational outputs from GFS/ECMWF/Met O, for his forecasting for the week ahead.

Edited June 27, 2011 by johnholmes

[Backtrack]

The models have gotten it badly wrong today.

24.4C here at 9.20am, in 100% sunshine?

If this continues it will be 30C today, it wasn't supposed be as high as 22C today, never mind 24C at 9am!

[snowmadchrisuk]

Yes real scorcher in deed , little puzzled why GFS seems to have dropped support for the England / SE thunderstorms though . All the other weather sources are going for it as well as the news . Although I must say I expected a storm breaking out in the SE last night and nothing did. Guess we will have to wait and see.

Edited June 27, 2011 by snowmadchrisuk