Model Output Discussion 12z 08/07/13

[East_England_Stormchaser91]

conjecture? My comment was based on the model output, primarily from gfs. It clearly shows the Atlantic being let in, it has been showing this trend for days now. So those suggesting im hopecasting, clearly aren't looking at the models. Further, the ecm and ukmo only reinforce this trend to a more unsettled theme, with the Atlantic becoming more active. At this point, the beginning of August does appear unsettled, with the Azores high being flattened.its funny that those who have been suggesting th azores high would reinsert itself aren't accused of conjecture or hopecasting, when the models have been showing for days now the exact opposite. Its okay when it shows HP in FI, different when its the LP system involved!

GFS has been pushing and pushing this 'breakdown' back for days now though. Thought last Sunday was game over for the heat about Wednesday and Thursday last week? Only turned out to be the hottest day that far in this persistent heatwave. 

Think we would have had this breakdown by today if GFS FI was correct too? Yet we are potentially about to see temperatures soaring to 33-34c into next week. 

Look more to the stuff happening in the more reliable and accurate timeframe, then what you point out might be a bit more logical and correct. 

[summer blizzard]

well... the heat should be with us for another week, but with changes.

 

as the high drifts to our north, then east (or northeast) we look like getting a short spell of easterlies which will peg the temps alittle on the eastern half of the uk, before a southeasterly draft brings warmer, more himid weather next week. thunder/showers chances increasing as the week goes on, bright milky skies taking over from blue. by the end of next week current runs agree on a breakdown as the cut off low traverses the country bringing alot of heavy rain and embedded thunderstorms.

 

afterwards?... well much has been said about a re-load, and thats what i personally want. but the gfs has other ideas, suggesting (yet again) that the atlantic will kick in, thus removing the current pattern. and the azores high becomes our foe (for heat lovers)

Rtavn2401.png

 

the mjo appears to suggest an eventual orbit into phase 1

ALL_emean_phase_full.gif

 

which for july would suggest

JulyPhase1500mb.gif

 

so make the most of the heat, it looks like a gradual deterioration over the next week before we lose it, and theres no tangible sign of a quick return, of course this applies to fi, so theres time for change, but thats what the models are showing atm.

I'd be wary of that MJO forecast, it,s not often that we get such a reversal and the models are typically too bullish compared to reality.

[OldMetMan]

GFS has been pushing and pushing this 'breakdown' back for days now though. Thought last Sunday was game over for the heat about Wednesday and Thursday last week? Only turned out to be the hottest day that far in this persistent heatwave. Think we would have had this breakdown by today if GFS FI was correct too? Yet we are potentially about to see temperatures soaring to 33-34c into next week. Look more to the stuff happening in the more reliable and accurate timeframe, then what you point out might be a bit more logical and correct.

It might be worth pointing out again that, in blocked situations, especially winter blocks, the GFS has a tendency to want to keep turning the pattern zonal. Therefore, I agree that long-term GFS output is to be treated with even more suspicion than normal!

[Weather Boy]

In an attempt to summarise the models, it seems to me that all are showing a decline in pressure for next week, accompanied by the drawing up of some very warm humid air from S/SE.  A decline in pressure does not equal a breakdown.

 

The low everyone is referring to is, on all models, a pretty slack affair (as is the continental flow) and so I would anticipate that we are talking about storms potentially being imported from France, plus some home grown, such that on any given evening if you catch one, you will be soaked, or you will be bone dry: either way another roaster the following day. 

 

The low shown is, to my eye NOT indicative of a full scale breakdown with Atlantic frontal systems etc.  Rather we are talking about some thundery showers which could occasionally be quite widespread.

 

May I just make a generaly about these scenarios which is not strictly model related?  I wasn't model watching during the last prolonged heatwave 7 years ago.  However, I do know from experience that the Met weather forecast is often too progressive with breakdowns, and when they happen, they are blips e.g mid-July 2006, a supposed breakdown resulted in the odd shower and a reduction of temperatures from 34 odd to 27 before back up to 35!  Seeing as the Met forecast is largely based on models, that suggests to me that they too are somewhat too progressive.  They are programmed to look for a solution that resumes 'normal service'.  Hence the little breakdown from the NW mid-week has been totally dropped.

 

Currently the Meto describe more unsettled weather at the end of next week as "possible" and from 1 August they currently say, "there is a good deal of uncertainty", so they are not even definitely predicting a breakdown next week just now.  Therefore I'm afraid that anyone making assertions about August's weather doesn't have a clue, same as everyone else, and newbies should ignore them, as should we all (unless it's part of a LRF, in which case, it's just an interesting opinion).

 

The lesson to be learned is that no breakdown is yet nailed and if it becomes reality, it seems unlikely (at the moment) to be a full scale back-to-the-Atlantic stuff.  Next week is definitely going to be hot though, and it will be interesting to see if and when heat alerts will come out again.

Edited July 18, 2013 by Weather Boy

[Troubleatmill]

Not model related but interesting none the less,Paul Hudson on Look North last night said another week of hot then going out with a bang before jet stream moves back south!Might be worth a shout over next few days runs!?!?

Dont want it to move south, want it to stay north...thats if you want warmth and sun from the continant, want it south in winter, its all want want want lol 

[Troubleatmill]

The ECMWF ens are a real mixed bag out to next thurdsay, some have a fairly deep low affecting the uk and some have high pressure still dominating,  some more have us in a middle ground of no particular pressure, just about prety much anything can happen in that set up:

 

 

 

 

 

Edited July 18, 2013 by tempestas

[OldMetMan]

Some early thoughts on today's model output so far and where we actually are at the moment.

One thing that caught my eye this morning is on the Jetstream analysis.

The southern stream, running into Spain and the Med seems to be strengthening and this appears to be backed up by the cloud motion at that latitude. As I see it, this gives more impetus to falling pressure to the S and SE. That, together with a disrupting Atlantic trough feeding in from the NW, seems likely to increase this development

It's common for such blocked patterns as we have, summer or winter, to break down from the S or SW, as I mentioned the other day. If you want to see a good example of this in summer look at what happened at the end of August 1976. However, there still seems to be no clear cut evidence yet of a major change of pattern. Yes, there does seem to be a likelihood of falling pressure and hot humid air drifting our way next week with the changes mentioned above, yet, at this stage, I think it more likely that HP will reassert itself within a few days of the thundery breakdown, as LP to our S and SE fills again.

Nevertheless, it's still worth keeping an eye on the N American jet strength and orientation. I still believe that we will end up with a slow moving 500mb vortex to our W or SW, it's just a matter of when. With no Atlantic tropical disturbances around right now to enhance the upper flow, as I keep saying, it could take a long time.

I think later output today may give us a better picture.

[NorthNorfolkWeather]

Fantasy island is this Monday.   So much can change in that time, this low where it positions in the Bay of Biscay or directly over us is very crucial on how we move forward over the next 7-10 days. The CFS looks pants now for the next month, god knows what sweets they are feeding it but generally it's a reliable indicator.  Let's hope this time it's wrong!! As the Summer Monsoon season will begin...

 

 

Yes, some quite large differences between the 3 models at  T120.

 

ECM, to me looks messy, has the cut off low off Biscay but doesn't seem to know where the pressure gradient sits over France

 

 

GFS, makes less of the low and more of the heat with the really hot air considerably further North, but not at our shores

 

 

UKMO and the Fax chart to me look quite dissimilar, with more heat being pumped north on the FAX Chart (by about 200 miles) compared to the Model

 

 

 

One thing is certain, it will not be cool

Edited July 18, 2013 by NorthNorfolkWeather

[NO LONGER POSTING]

In an attempt to summarise the models, it seems to me that all are showing a decline in pressure for next week, accompanied by the drawing up of some very warm humid air from S/SE.  A decline in pressure does not equal a breakdown.

 

The low everyone is referring to is, on all models, a pretty slack affair (as is the continental flow) and so I would anticipate that we are talking about storms potentially being imported from France, plus some home grown, such that on any given evening if you catch one, you will be soaked, or you will be bone dry: either way another roaster the following day. 

 

The low shown is, to my eye NOT indicative of a full scale breakdown with Atlantic frontal systems etc.  Rather we are talking about some thundery showers which could occasionally be quite widespread.

 

May I just make a generaly about these scenarios which is not strictly model related?  I wasn't model watching during the last prolonged heatwave 7 years ago.  However, I do know from experience that the Met weather forecast is often too progressive with breakdowns, and when they happen, they are blips e.g mid-July 2006, a supposed breakdown resulted in the odd shower and a reduction of temperatures from 34 odd to 27 before back up to 35!  Seeing as the Met forecast is largely based on models, that suggests to me that they too are somewhat too progressive.  They are programmed to look for a solution that resumes 'normal service'.  Hence the little breakdown from the NW mid-week has been totally dropped.

 

Currently the Meto describe more unsettled weather at the end of next week as "possible" and from 1 August they currently say, "there is a good deal of uncertainty", so they are not even definitely predicting a breakdown next week just now.  Therefore I'm afraid that anyone making assertions about August's weather doesn't have a clue, same as everyone else, and newbies should ignore them, as should we all (unless it's part of a LRF, in which case, it's just an interesting opinion).

 

The lesson to be learned is that no breakdown is yet nailed and if it becomes reality, it seems unlikely (at the moment) to be a full scale back-to-the-Atlantic stuff.  Next week is definitely going to be hot though, and it will be interesting to see if and when heat alerts will come out again.

 

Sorry but this post is fantastic slaps all you people who take one model run and then think that is it.. Just like in winter...people who think they can predict the weather 1 week in advance even 3 plus days.. You would be billionaires by now.. 

 

As far as we can tell from the models... In summery and simple..

 

Weekend: Slightly cooler 25-28 by no means cold like some people seem to think it will be an ice age!

 

Next week: VERY HOT! Humid and the risk of thunderstorms...

 

Further into the week: I have no idea nor does anybody else!

[Paceyboy]

Good post Mushy...clearly changes are afoot and it's perhaps not surprising that the models are all struggling to nail the detail, but I'd expect things to become a good deal clearer across the next 48hrs.

 

UKMO was first to pick the change this time yesterday and it remains fairly consistent this morning, so for my money it is probably closest to the mark at 144hrs on todays outputs, but I'm pretty sure it will not be exactly right at this range.

 

As for the post breakdown period, GFS looks ugly if fine, warm and sunny weather is your bag, with the Atlantic door fully open and a fairly unsettled picture developing. ECM at 240hr has a rather more sluggish look to things, but it does appear as though systems would begin to slide in from the west if it went out to T+264 or T+288hrs; so to suggest an imminent return to fine, settled weather into early August is little more than wishful thinking imo....at least for now.

 

The other interesting thing this morning is just how much the models have downgraded the weekend maxima. Yesterday I said I was surprised to see the local BBC forecast only going for 24c here on Sat, that seemed several degrees to low, but now GFS has fallen firmly in line.  Now before anyone goes jumping up and down about GFS undercooking maxima, the fact is these numbers are significantly lower than those progged for Saturday only 24hrs ago and if right it would feel pretty cool from Kent to Kirkwall, especially on the coast.  Ultimately it will be interesting to see how Sat's actual max's compare with this prediction from GFS..

 

SHEDHEAD- That is a chart to suit your agenda! It seems you have used the snapshot of the minimum temps not the max temps that day

The max temp  chart (the one I always see quoted on here)

shows 26-28C from London to Manchester southwestwards!

Edited July 18, 2013 by Paceyboy

[Captain Shortwave]

SHEDHEAD- That is a chart to suit your agenda! It seems you have used the snapshot of the minimum temps not the max temps that day

The max temp  chart (the one I always see quoted on here)

shows 26-28C from London to Manchester southwestwards!

Here is the max predicted values for Saturday at 15:00 (GFS 00z, will probably shove the 06z output below this when it comes out)

06z

 

 

I will make sure to wear as much green as possible to express my feelings to you lucky inland people 

Edited July 18, 2013 by Captain shortwave

[shedhead]

SHEDHEAD- That is a chart to suit your agenda! It seems you have used the snapshot of the minimum temps not the max temps that day

The max temp  chart (the one I always see quoted on here)

shows 26-28C from London to Manchester southwestwards!

It was simply an error, here is the max from Wz, can't lift it off NW as it's about to update.

 

Still looks pretty cool from Kent to Kirkwall and only 27c here where 30-32c was being predicted for Sat recently.  That and that

alone was my point, hope you now get it.

 

[TEITS]

The outlook in my eyes is very clear based on my own views and the model output.

 

Firstly max temps next week are difficult to pin down although around 30C is widely possible. However just the slightest shift in synoptics can result in temps being much higher than that i.e mid 30s. The peak of the hot spell remains towards the latter part of the week but with it comes increased storm potential. Thereafter its pretty clear to me it will turn much cooler from the W with temps dropping to the low 20s.

 

So plenty to look forward to because we have the wonderful combination of very high temps and increasing storm potential. Remember in these situations the hottest temps generally occur on the last day of the heatwave before the storms and cooler W,lys spread E.

[Bristawl Si]

 

It was simply an error, here is the max from Wz, can't lift it off NW as it's about to update.

 

Still looks pretty cool from Kent to Kirkwall and only 27c here where 30-32c was being predicted for Sat recently.  That and that

alone was my point, hope you now get it.

 

Only 27C!! Shock, horror - it's a drastic cooldown!

Give it a rest on temperature nit-picking.

27c is hot .....end of.

[TEITS]

It was simply an error, here is the max from Wz, can't lift it off NW as it's about to update.

 

Still looks pretty cool from Kent to Kirkwall and only 27c here where 30-32c was being predicted for Sat recently.  That and that

alone was my point, hope you now get it.

 

Sorry but I strongly disagree.

 

The temps for the E/SE have been predicted to be much lower on Saturday for several days now and I commented about this due to the E,ly flow off the N Sea having a knock on effect on the temps.

 

By the way I would hardly call temps still 4C above average as cool. A cool max temp in July would be around 17C.

[shedhead]

 Only 27C!! Shock, horror - it's a drastic cooldown!Give it a rest on temperature nit-picking.27c is hot .....end of.

No one is saying 27c is not hot, what I am saying is it is 3-5c cooler that what was being predicted for Sat recently.  Now if the max for Sat recently was being progged at 27c, then today it shot up to 32c people would rightly be discussing it. So what makes it different when it goes the other way?

Edited July 18, 2013 by shedhead

[joggs]

The outlook in my eyes is very clear based on my own views and the model output.Firstly max temps next week are difficult to pin down although around 30C is widely possible. However just the slightest shift in synoptics can result in temps being much higher than that i.e mid 30s. The peak of the hot spell remains towards the latter part of the week but with it comes increased storm potential. Thereafter its pretty clear to me it will turn much cooler from the W with temps dropping to the low 20s.So plenty to look forward to because we have the wonderful combination of very high temps and increasing storm potential. Remember in these situations the hottest temps generally occur on the last day of the heatwave before the storms and cooler W,lys spread E.

I go along with all you say teits due to the fact you called this whole pattern spot on from early July lol.Cracking forecasting and intuition there fella.

[shedhead]

Sorry but I strongly disagree.

 

The temps for the E/SE have been predicted to be much lower on Saturday for several days now and I commented about this due to the E,ly flow off the N Sea having a knock on effect on the temps.

 

By the way I would hardly call temps still 4C above average as cool. A cool max temp in July would be around 17C.

I was referring to Ilchester, not E or SE and according to GFS 17-21c looks pretty widespead across the E within 20 miles of the coast... IF it is correct that is of course. 

[Frosty.]

It might be worth pointing out again that, in blocked situations, especially winter blocks, the GFS has a tendency to want to keep turning the pattern zonal. Therefore, I agree that long-term GFS output is to be treated with even more suspicion than normal!

Precisely, the Gfs has an eastward bias and a default to zonal mode which is why I take the low res gfs with a bucket load of salt whatever it is showing, as for the current models/weather, i'm loving this heatwave and it now looks like next week will become even hotter and much more humid and continental with an increasing risk of scattered thunderstorms breaking out but with a lot of scorching sunshine.

[nitro_deluxe]

Plenty to get our teeth into the next few days then? ETA for the prolonged sunshine and heat to clear away still uncertain, ditto re storm location, arrival,severity.. Bags of potential for the latter - as already mentioned above, temps may well peak before any cooler air attempts to infiltrate. The ingredients remain, cooking away accordingly, before (hopefully) being served up on a biggish plate!

Let's enjoy the moment - no need for petty bickering, point scoring or nit picking - all opinions valued, welcomed, a little polite diplomacy or should one disagree? Goes a long long way..

The goods for heat lovers have finally arrived - hopefully next for storm lovers..anyone left out? Your turn will arrive, I.e., perhaps slightly more mundane conditions. This is a pretty rare synoptic situation for the UK - hence the added difficulty of predicting what may or may not happen next? Enjoy..

Cheers!

Edited July 18, 2013 by triple_x1

[storm1080]

GFS 6z T93 has this iberian low more strung out N to S...vs previous run

[storm1080]

Interesting latest GFS chart with precip chats loaded, seem to do away with any LP rotation post T93

[Troubleatmill]

Looking out west, im not too struck on the lp crossing the atlantic at t132 on the 06z looking as though it may undercut the HP in a clean move

Edited July 18, 2013 by tempestas

[storm1080]

Looking out west, im not too struck on the lp crossing the atlantic at t132 on the 06z looking as though it may undercut the HP in a clean move

we're both looking at this from the same viewpoint too ;-)

[Methuselah]

Can we please all stop the petty bickering and nitpicking? We all know, or should know by now, that each and every model run is slightly different from its predecessor...It's not exactly something new...