Model Output Discussion

[TEITS]

The runs make me wonder because following the 1-2 days of warmth we have, things return to below average for the forseeable future (see ensembles), and I cannot recall a time when below average weather gave way to an intense warm few days then back to below average, it's quite strange. So in my opinion the warm spell for the weekend will either be significantly downgraded (which is a very very real possibility, looking at other model outputs), or the post weekend outlook will become much better (which I think is the less likely option looking at the Atlantic Oscillations.

I very much doubt Sun/Mon will be downgraded. The question is can E Anglia/SE squeeze another hot day on Tuesday? That for me is the uncertainity at the moment.

[Harry]

I very much doubt Sun/Mon will be downgraded. The question is can E Anglia/SE squeeze another hot day on Tuesday? That for me is the uncertainity at the moment.

Well, excluding the CAPE/LI figures which are ludicrously high at the moment and guaranteed to be at least halved (IMO)!

[Summer Sun]

UKMO, ECM, and GFS all seem to be forecasting a warm/very warm Sunday away from the NW... which models are suggesting a significant downgrade of this?

SP isn't talking about the models he's talking about the ensembles - http://www.netweather.tv/index.cgi?action=ensviewer;sess=

[NickR]

SP isn't talking about the models he's talking about the ensembles - http://www.netweathe...ensviewer;sess=

I see nothing but consistency there for the weekend, which was the period SP was addressing.

[SP1986]

UKMO, ECM, and GFS all seem to be forecasting a warm/very warm Sunday away from the NW... which models are suggesting a significant downgrade of this?

In comparison to the GFS 6z - all of them although it's not technically a downgrade. It would take something impressive to sustain the GFS 6z conditions in the next few runs. Who knows though stranger things have happened. That will not mean it won't be warm of course, just not as warm as the 6z atmospheric values suggest at 850hPa.

The consistency for the weekend comes in the ECM, UKMO and GEM all of which suggest roughly a maximum of around 12C at 850hPa... however it may be warmer at ground level that the GFS 6z suggests due to lower humidity. The GFS generally was the warmest of all the models by quite a margin.

Not to say it won't happen of course!

[SP1986]

ENS runs are usually the best runs to look at as they look the overall mean synoptics and they take into account all of the model outputs. (Only available of WZ so apologies for those who are not familiar with the setup)

Saturday

Sunday

Monday

A promising outlook though, although by next week pressure falls away.. interestingly though the ENS graphic mean is having none of the low shown by the individual ECM run which suggests it is unlikely to occur as touted earlier

[Milhouse]

The runs make me wonder because following the 1-2 days of warmth we have, things return to below average for the forseeable future (see ensembles), and I cannot recall a time when below average weather gave way to an intense warm few days then back to below average, it's quite strange.

Remember 4 or 5 days ago the upcoming weekend was showing up as below average on the ensembles only for a dramatic rise to occur in the past few days. The fact that the ensemble mean returns to slightly below average next week shouldnt be taken too seriously at this point.

[Thundery wintry showers]

The runs make me wonder because following the 1-2 days of warmth we have, things return to below average for the forseeable future (see ensembles), and I cannot recall a time when below average weather gave way to an intense warm few days then back to below average, it's quite strange. So in my opinion the warm spell for the weekend will either be significantly downgraded (which is a very very real possibility, looking at other model outputs), or the post weekend outlook will become much better (which I think is the less likely option looking at the Atlantic Oscillations.

It's rare, but I remember that in Junes 1998 and 2000 we had a notable heatwave in the third week of both months, and mostly near or below average temperatures elsewhere in the two months (though June 2000 ended up quite warm overall in the south). July 1998 had a brief heatwave in the south on the 19th/20th, though that one was largely confined to the south of England, and temperatures elsewhere in the month were mostly below average.

[Harry]

It's rare, but I remember that in Junes 1998 and 2000 we had a notable heatwave in the third week of both months, and mostly near or below average temperatures elsewhere in the two months (though June 2000 ended up quite warm overall in the south). July 1998 had a brief heatwave in the south on the 19th/20th, though that one was largely confined to the south of England, and temperatures elsewhere in the month were mostly below average.

I might be wrong, but that June 1998 heatwave brought some dramatic night time thunderstorms too

[chionomaniac]

ENS runs are usually the best runs to look at as they look the overall mean synoptics and they take into account all of the model outputs. (Only available of WZ so apologies for those who are not familiar with the setup)

A promising outlook though, although by next week pressure falls away.. interestingly though the ENS graphic mean is having none of the low shown by the individual ECM run which suggests it is unlikely to occur as touted earlier

Looking at the ensemble mean is a useful tool but one should be aware of some traps. For instance, there could be two equal clusters of ensembles at each end of the scale which would give two quite different distinctive outcomes that would be quite different from the mean. Even if the clusters weren't equal the distortion could still be misleading.

Edited June 22, 2011 by chionomaniac

[Summer Sun]

Maybe next week will throw up some suprises, what looks 90% certain is the south at least will see warm and locally hot tempertures till Tuesday, now beyond then is uncertain, some models are showing the High moving back into France, where as UKMO and NOGAPS keep the low just North of Scotland

There will be a few twists and turns to come yet i feel, the met office are saying everywhere will be cooler by Wednesday so who knows what will happen.

[Thundery wintry showers]

I might be wrong, but that June 1998 heatwave brought some dramatic night time thunderstorms too

The June 1998 one delivered significant thunderstorms to west Wales, eastern Ireland, NW England, western Scotland and the far SE, while the July 1998 one delivered significant thunderstorms to East Anglia and the southeast and weaker ones over NE England. I think the July 1998 one is the more likely to have affected the London area. On the other hand I recall that June 1998 was quite a thundery month generally so you might be recalling some other event from that month.

In contrast the June 2000 one produced surprisingly little thunder activity, highlighting how "hit and miss" these "plume" situations can be. The timings have to be right to deliver more than a scattering of thundery showers.

[Harry]

The June 1998 one delivered significant thunderstorms to west Wales, eastern Ireland, NW England, western Scotland and the far SE, while the July 1998 one delivered significant thunderstorms to East Anglia and the southeast and weaker ones over NE England. I think the July 1998 one is the more likely to have affected the London area. On the other hand I recall that June 1998 was quite a thundery month generally so you might be recalling some other event from that month.

In contrast the June 2000 one produced surprisingly little thunder activity, highlighting how "hit and miss" these "plume" situations can be. The timings have to be right to deliver more than a scattering of thundery showers.

Indeed. What has been clear over the past few years where we've had very 'blocking' weather patterns, is that if a plume persists for a significant period without destablisation in the form of a front/trough, jet streak or weak cap (or combination) (my guestimation based on the last few years would be in the region of 4-5+ days), the atmospheric profile becomes saturated and the initial high level of instability decreases, giving way to more persistent, torrential rain, rather than thunderstorm cells. This is not the case however where wind direction shifts and fresh moisture is injected.

Edited June 22, 2011 by Harry

[AWD]

The UKMO and GFS are having none of a thundery bang on Monday/Tuesday now, keeping the LP further north and the south gradually getting cooler but still warm and pleasent!

What's it going to take to get a big bang nowadays!!!!

[Kentish Kiwi]

The UKMO and GFS are having none of a thundery bang on Monday/Tuesday now, keeping the LP further north and the south gradually getting cooler but still warm and pleasent!

What's it going to take to get a big bang nowadays!!!!

Cape + Lifted Index looks pretty high on the GFS 06z...

Personally (and this is just being greedy and hypothetical) I would love to see a mix of the GFS 00z and the 06z, with the intense heat shown over Sun/Mon/Tues on the 06z followed by the settled and increasingly warm conditions of the 00z in the medium/longer term. I wonder if such an evolution is synoptically viable...

Edited June 22, 2011 by Kentish Kiwi

[Harry]

The UKMO and GFS are having none of a thundery bang on Monday/Tuesday now, keeping the LP further north and the south gradually getting cooler but still warm and pleasent!

What's it going to take to get a big bang nowadays!!!!

Where's GFS saying that AWD?

Again, as much hype and excitement there's been, there's still too big a timeframe between now and Sunday/Monday/Tuesday.

Based on the 06z GFS, there is little reason to suspect a bang won't happen.

[AWD]

Where's GFS saying that AWD?

Again, as much hype and excitement there's been, there's still too big a timeframe between now and Sunday/Monday/Tuesday.

Based on the 06z GFS, there is little reason to suspect a bang won't happen.

Admittedly my post might have been slightly IMBY, as having a deeper look, the GFS does keep the ingredients good for Eastern England, inparticulary East Anglia! However, it's nothing like the ECM which would provide a large part of the country with a light show on Monday/Tuesday! The GFS isn't good for Western and probably Central parts of the country! GFS has very little PPN over the south of the country!

Like you said though, Monday onwards is far from decided yet, with different outcomes being brought up by different model runs so patience and hope is probably needed for now!

I'll be looking for a westard trend in tonight GFS, and also hoping the ECM keeps it similar to it's earlier run!

[Harry]

Admittedly my post might have been slightly IMBY, as having a deeper look, the GFS does keep the ingredients good for Eastern England, inparticulary East Anglia! However, it's nothing like the ECM which would provide a large part of the country with a light show on Monday/Tuesday! The GFS isn't good for Western and probably Central parts of the country! GFS has very little PPN over the south of the country!

Like you said though, Monday onwards is far from decided yet, with different outcomes being brought up by different model runs so patience and hope is probably needed for now!

I'll be looking for a westard trend in tonight GFS, and also hoping the ECM keeps it similar to it's earlier run!

Also, irrespective of what charts suggest, features such as MCS' frequently 'do their own thing' and can move independently of prevailing winds etc and are, effectively, unpredictable.

I'm not very curious at each and every run - 12z should be out in the next hour or so.

Edited June 22, 2011 by Harry

[Summer Sun]

High's over Greenland are continuing to drop, and warming up nicely by Saturday,

A little while away i know but that low to our NW maybe worth keeping an eye on,

Edited June 22, 2011 by Gavin D

[Eugene]

GFS 12Z OP trending to push the plume further east with our continental cousins getting the most of it as usual, not much surprise really as plenty of 06Z ensemble runs did the same.

Edited June 22, 2011 by Eugene

[Summer Sun]

GFS 12Z OP trending to push the plume further east with our continental cousins getting the most of it as usual, not much surprise really as plenty of 06Z ensemble runs did the same.

I'd have to agree with you, unless this pesky LP to our north shifts i can see more downgrades over the coming day's, maybe mid 20's are more realistic now for the south unless ECM is different of course

Edited June 22, 2011 by Gavin D

[Costa Del Fal]

Quite a downgrade for Monday. Storm conditions gone and the high uppers over the continent but to be expected really. But who knows it may return.

Greenland Blocking is back with a vengeance again on the runs however High pressure hanging in for a while at least throughout the run.

Edited June 22, 2011 by Blizzards

[Summer Sun]

There is still hope for July

[SP1986]

As I suspected the 6z was a little unrealistic, but the 12z is really keen on shortening the length of the warm spell. Not only does it do that but it reinforces northern blocking big time which is not allowing the low to move anywhere. Without wanting to sound pessimistic, this is not the direction we want things to be going if looking for a period settled warm weather. It feels like one step forward, two steps back!

They key is, unless we see that Northern blocking completely disappear then we are not going to see any sustained 'summery' weather. From the looks of it, from the oscillation, other model runs, for the moment, that northern blocking is here to stay.

That said it's only one run, but the GFS is arguably the most influential model, so it is a little worrying.

[Cecil Hogmanay Melchett]

Have to say im very disappointed with todays output.The heat is pretty much a 48hour incursion and the signs are there that that godforsaken atlantic is going to take over again after monday.That semi permanent trough just sticks like a limpet to our western shores.

If anything im leaning towards july starting pretty much as june has been,heaps of high pressure to our NW with a trough sat over or just to our west.

Like i said,very disappointed and worrying signs after the brief warm up sun/mon.