Model Output Discussion 12z 08/07/13

[Captain Shortwave]

Wow whilst an operational can flip around from run to run, you rarely expect the ensemble mean to do the same thing. 

 

Previous run

[Cheshire Freeze]

There was certainly some premature self back-slapping going on last night. We shall see, but the Azores High is the form horse this summer.

Hang on a minute, what makes the modelling more supremely accurate today than yesterday? No one was back slapping, just highlighting where we may be headed as we progress through July?I HATE the fact that some people find it so difficult to prevent personal preferences tainting their analysis. Impartiality- it's not hard, honest!Quotes such as 'the Azores high is form horse this summer' is as much an assumption (if not more of one) as someone using the current and modelled teleconnections to produce a late July forecast! Edited July 9, 2013 by CreweCold

[Buzzit]

Have a question; half rhetorical, half not, but why is it bonkers?

 

I'm not saying that it's likely to verify or anything, but synoptics can change dramatically in 48 hours, so why not that?  Do you mean lack of background signals in support?

From my viewpoint there is not even anything on the operational charts to support a high filling in the way it does and with the strength it has from nothing 24 hours earlier..  My fairest conclusion is that models are struggling with this Sunday and what will happen next - range of options on the table but none are decided as yet. As another example I find it strange that we go from this to this over 90 hours.

 

[Methuselah]

Indeed: the models are struggling; but, then they nearly always do...Perhaps the charts that John Holmes posts are the best indications, just now?

Edited July 9, 2013 by A Boy Named Sue

[Harry]

With a bias heart I am viewing the ECM 00z very fondly indeed while noting the Monday 12z looks less appealing. 

 

We have a week of w/c 22nd July and with the site of the Azores High trying to re-build it feels me with hope....I'm not sure I could cope with a mid-Atlantic ridge during that week....little convective potential, little heat, slack/moderate murky NW'erlies.......am praying a setup either like we have now or a plume type scenario emerges!!!

 

I feel there's going to be many swings as the models try and get a hold of what's happening in the days ahead, never mind the best part of 14!

 

[Downpour]

Hang on a minute, what makes the modelling more supremely accurate today than yesterday?No one was back slapping, just highlighting where we may be headed as we progress through July?I HATE the fact that some people find it so difficult to prevent personal preferences tainting their analysis. Impartiality- it's not hard, honest!Quotes such as 'the Azores high is form horse this summer' is as much an assumption (if not more of one) as someone using the current and modelled teleconnections to produce a late July forecast!

 

 

Hang on a minute, what makes the modelling more supremely accurate today than yesterday?No one was back slapping, just highlighting where we may be headed as we progress through July?I HATE the fact that some people find it so difficult to prevent personal preferences tainting their analysis. Impartiality- it's not hard, honest!Quotes such as 'the Azores high is form horse this summer' is as much an assumption (if not more of one) as someone using the current and modelled teleconnections to produce a late July forecast!

The Azores High has been the predominant force this summer and remains so. As long as we assume there will be a breakdown at some point, you cannot ever be wrong... but any breakdown remains in FI. 

[johnholmes]

looking at some longer term drivers or whatever you wish to call them as of today

well after 20 mins work it will not let me upload the pdf file so I will try to load just the words, please check the charts for yourself-sorry

I copied this into the above thread or possibly the model thread after the usual monthly e mail from NOAA

Most model forecasts continue to indicate ENSO-neutral (Niño-3.4 index between -0.5°C and

0.5°C) into the Northern Hemisphere winter 2013-14. The statistical model forecasts remain cooler in the

Niño-3.4 region relative to the dynamical models forecasts (Fig. 6). The forecast consensus favors

ENSO-neutral (near 60% or greater) into the Northern Hemisphere fall 2013 (see CPC/IRI consensus

forecast).

I am no expert so I will leave this prediction to others to suggest how this may affect the North Atlantic weather through the latter 2/3’ds of our summer.

Turning to the MJO, first the actual

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/whindex.shtml

This shows the orbit to be very low and in phase 1 to 2.

The composite 500mb charts for late June July for 1 are below

With same period for phase 2

The current 500mb chart is below

So in spite of a very low amplitude the phase 1 fits better than the phase 2 in this case-not perfectly but then perfect is not a word weather forecasters are often seen/heard to use!

If we look at these two phases for early July, see below, side by side and compare with what we have?

Phase 1 on the left and phase 2 on the right.

Really neither fits very well.

So to the forecast for July

To me it appears to suggest little real change from its actual with a preference for phase 1 rather than phase 2, again in low orbit.

This would, according to the above charts suggest a ‘better’ upper air pattern than two would. Even so it is low orbit and to my mind this never equates to any real direction as to how the upper air pattern might look 10-30 days down the line.

Other factors that folk sometimes use are the AO and NAO. What we have to remember here is that they are really only indicators of what the synoptic surface pressure pattern the models are currently indicating. Thus they to me have only very limited use. As one might expect if you follow them regularly then you fairly soon discover that, similar to the synoptic model outputs, they show reasonable accuracy for about 7 sometimes 10 days then drift quite badly when comparing their prediction to what actually happens.

Anyway AO and NAO below

Neither suggests a raging Atlantic but neither is conclusive evidence of any major blocking.

So there we are, to me the 500mb anomaly charts are the best guide 10-15 possibly 18 days or so ahead. The latest outputs from the main 3 are showing some sign of another +ve area of heights in the Atlantic which is where the last (the current) set up came from, although they tended to show further SW than the current charts suggest.

Summing up then for the weather at the level we live at. No raging Atlantic and no repeat being suggested by the anomaly charts, of the last summer weather. Neither do they yet suggest anything approaching the longer hot summers, say 2006 or one or two in the 90’s. But better than last year it would seem using the current and charts over the last week or so.

John

[shedhead]

The Azores High has been the predominant force this summer and remains so. As long as we assume there will be a breakdown at some point, you cannot ever be wrong... but any breakdown remains in FI. 

The exact same is true in periods of poor weather tho. As long as we assume there will be an improvement at some point, you cannot ever be wrong... but that does not stop people looking for and commenting on likely improvements, often deep, deep in FI. Therein lies the root of most disagreements in the MOD, for some reason it's perfectly acceptable to comment on the chances of cold winter weather or hot summer weather post T+300, but when commenting on mild winter weather or cool summer weather FI almost always starts when any change is progged to take place.  That is why the vast majority of posts in here belong in the moaning thread, with only a very small % of members being able to consistantly post without demonstrating a clear weather preference. 

Edited July 9, 2013 by shedhead

[Harry]

The Azores High has been the predominant force this summer and remains so. As long as we assume there will be a breakdown at some point, you cannot ever be wrong... but any breakdown remains in FI. 

 

This isn't strictly speaking a fair statement - only since very late June and so far during July has it been a dominant force.

 

In any event one can argue the Azores High is a dominant force at all stages in our summers, whether it's slap bang over us or Europe bringing warm/hot weather, or whether it sticks over the mid Atlantic bring us cool and often unsettled weather.

 

Thus far both GFS and ECM sees the AH exacting fairly strong influence over our weather, albeit it retreating West on occasions before signs of building back in....typical summer in many respects. 

[mushymanrob]

Well it's my friend this week!

 

 

Indeed. Given that the AH has been giving us the superb conditions we have had for much of the summer this endless "the Azores High is the enemy" schtick from Mushy is becoming increasingly bizarre. Another good outlook on the reliable timeframe this morning for most of us.

 

... but its only our freind when its displaced, or has ridged over us. when it sits there, at home over the azores, it simply directs the atlantic systems towards us (like the last month or so). one could argue that when the azh is displaced, its no longer the azh!

 

nah, give me a euro high anyday, at least theres a thunderstorm potential, theres no chance with the azh being the azh.

[Cheshire Freeze]

The exact same is true in periods of poor weather tho. As long as we assume there will be an improvement at some point, you cannot ever be wrong... but that does not stop people looking for and commenting on likely improvements, often deep, deep in FI. Therein lies the root of most disagreements in the MOD, for some reason it's perfectly acceptable to comment on the chances of cold winter weather or hot summer weather post T+300, but when commenting on mild winter weather or cool summer weather FI almost always starts when any change is progged to take place.  That is why the vast majority of posts in here belong in the moaning thread, with only a very small % of members being able to consistantly post without demonstrating a clear weather preference. 

 

Exactly this. Really winds me up. It's really not hard to be unbiased when assessing the NWP or the drivers which may affect the NWP output. My issue was that Downpour said himself that the Azores high was the 'form horse' which means in his opinion, anything other than a rampant Azores high in the output gets instantly disregarded. We just can't have this approach if we're to remain objective.

 

The Azores high (displaced) has only been a major influence in terms of summery weather for the past week or so. The ECM, GFS etc etc all show that the high will pull west slightly over the next 10 days. How far west and the extent of any troughing (if at all) is unknown at this stage. What looks certain however is that some areas will be prone to more cloud than recently as weak disturbances run around the HP system.

 

FWIW here is the latest CFS view for August

 

 

 

 

Edited July 9, 2013 by CreweCold

[shedhead]

This isn't strictly speaking a fair statement - only since very late June and so far during July has it been a dominant force.

 

In any event one can argue the Azores High is a dominant force at all stages in our summers, whether it's slap bang over us or Europe bringing warm/hot weather, or whether it sticks over the mid Atlantic bring us cool and often unsettled weather.

 

Thus far both GFS and ECM sees the AH exacting fairly strong influence over our weather, albeit it retreating West on occasions before signs of building back in....typical summer in many respects. 

Agreed, even if not over the UK it can have a major impact on the weather we see, just as in past weeks when it was responsible for helping to steer several troughs across us....I think it was Mushy who highlighted this at the time.  Even today we have a fat cell of Azores HP right over us, but it's still not everyones friend, with N Scotland and even parts of the East Anglian coast being keep pretty cool.  As a smal island in a cold ocean it's all about wind direction for us, the pressure could be 1032 here one day in a SE'erly at the max would be 30c, two days later the pressure could still be 1032 but if the high center had drifted into the Atlantic we could be 18c in a NW'erly.  Clearly a decent Azores High dominated pattern will give us the chance of a decent summer and as the centers wander around and the winds change it should ensure all of us see some very warm and sunny periods at times. In fact I see it as a great leveller, with the SE not always hogging all the heat, which is probably why most of the moaning has come from that part of the world of late...

Edited July 9, 2013 by shedhead

[mushymanrob]

I am unsure as to why you make such posts mushy

re the predicted max temperatures, for eastern England the models, last week, did not show N Sea low St for Monday, most outputs suggested it for Wednesday. Thus the max prediction even yesterday was wrong as they did not evne then get the St clearance time correct. No need to make so much about it-it happens, look for the reason rather than carping on about it, lesson learnt perhaps for next time for us?

re the MJO, not sure how 'up' you are on this topic as I find it very hard to really grasp. However most folk accept that when it is in low orbit, actual or predicted the 500mb charts can often be quite different. Best to remember that I suspect?

It really would do your status on here a power of good if you showed a bit more objectivity mate, I know you are not the only one but it needs saying.

looking at the ouput last evening from NOAA on the 500mb charts and it has started to show, especially on the 8-14 another build of heights over the Atlantic extending towards the UK, not too different from how it showed this current spell 10-12 days ago. This idea has been picked up on the ECMWF output this morning although not on the GFS. So, 'maybe' another build of pressure in about 10 days time. Certainly no sign of a repeat at the moment of wash out summer weather like last year.

 

 

possibly because i was frustrated at missing out on the real heat yesterday!

 

what i dont 'get' about the mjo is why there are so many often conflicting sets of data. at first i assumed there was only one , but that chart i posted (courtesy of another poster) has several predictive tracks. so which one do you chose to believe when they all appear to diverge in different directions?.

 

thought i was being objective john, as i see it the models are struggling to nail the exact detail sunday and beyond. but it does look atm like the core of this high will retrogress back home to the azores, opening the doors for the atlantic systems and jet to ride across us, albeit at a northerly latitude (so no washout, just similar conditions to the second half of june). please correct me IF this mornings runs didnt suggest this!

[johnholmes]

latest 500mb update 9 july 2013.pdf

this time it has done what I asked=yipee, but I will leave the post above as some say they cannot open a pdf file

Just to add;

I suspect the weather in late July is going to be a sort of N-S split, whether that takes the form of NE-SW or NW-SE is unclear but the southern half especially 1/3 of the UK having the driest and warmest and probably sunniest period.

re the models struggling mushy

In my view over 90% of the time they 'struggle' as do forecasters to 'nail the exact detail'. Too often folk expect detail such as max/min/rainfall amount/timing (snow in winter) etc etc to be spot on-that is fantasy island expectation really rather than what is often referred to as such at T+ whenever.

Edited July 9, 2013 by johnholmes

[mushymanrob]

Agreed, even if not over the UK it can have a major impact on the weather we see, just as in past weeks when it was responsible for helping to steer several troughs across us....I think it was Mushy who highlighted this at the time. Even today we have a fat cell of Azores HP right over us, but it's still not everyones friend, with N Scotland and even parts of the East Anglian coast being keep pretty cool.  As a smal island in a cold ocean it's all about wind direction for us, the pressure could be 1032 here one day in a SE'erly at the max would be 30c, two days later the pressure could still be 1032 but if the high center had drifted into the Atlantic we could be 18c in a NW'erly.  Clearly a decent Azores High dominated pattern will give us the chance of a decent summer and as the centers wander around and the winds change it should ensure all of us see some very warm and sunny periods at times, in fact I see it as a great levelller, with the SE not always hogging all the heat. 

 

guilty... hence my going on about the azores high being 'the enemy' (of summer) when it sits there over the azores.

[Cecil Hogmanay Melchett]

The exact same is true in periods of poor weather tho. As long as we assume there will be an improvement at some point, you cannot ever be wrong... but that does not stop people looking for and commenting on likely improvements, often deep, deep in FI. Therein lies the root of most disagreements in the MOD, for some reason it's perfectly acceptable to comment on the chances of cold winter weather or hot summer weather post T+300, but when commenting on mild winter weather or cool summer weather FI almost always starts when any change is progged to take place.  That is why the vast majority of posts in here belong in the moaning thread, with only a very small % of members being able to consistantly post without demonstrating a clear weather preference. 

LOL your one of the very worst culprits!!!

[Evening thunder]

I do think there are also members that post about unsettled trends more than settled ones in FI that balance out some of the 'mainly posing high pressure' posts. So I have also got the feeling occasionally that sometimes we are told that these warm/settled charts are in FI, but other time some post about trends to unsettled weather/breakdowns, or things staying unsettled, which are also in FI.

 

Re the Azores High. I can see Mushy's point when the Azores high is a true Azires high centered near th Azores. If it wasn't often near there or a trough was there NW Europe would probably be slightly warmer on average in summer due to a downstream ridge or warmer flow, rather than a NW flow. Never the less it can also be good for us if it ridges in enough (though not thundery warmth fans), or especially if it builds over us more or we get a closed surface high like now, but I'd probably sooner call what we have now a UK high rather than an Azores high..

Edited July 9, 2013 by Stormmad26

[Downpour]

The exact same is true in periods of poor weather tho. As long as we assume there will be an improvement at some point, you cannot ever be wrong... but that does not stop people looking for and commenting on likely improvements, often deep, deep in FI. Therein lies the root of most disagreements in the MOD, for some reason it's perfectly acceptable to comment on the chances of cold winter weather or hot summer weather post T+300, but when commenting on mild winter weather or cool summer weather FI almost always starts when any change is progged to take place.  That is why the vast majority of posts in here belong in the moaning thread, with only a very small % of members being able to consistantly post without demonstrating a clear weather preference. 

That's simply not true of everyone – you'll struggle to find a post from me pointing to a blizzard at T300, although I accept that it happens.

 

But let's stick to the models as they are – set fair in the reliable timeframe. Anything beyond that is little better than guesswork. 

[Downpour]

... but its only our freind when its displaced, or has ridged over us. when it sits there, at home over the azores, it simply directs the atlantic systems towards us (like the last month or so). one could argue that when the azh is displaced, its no longer the azh!

 

nah, give me a euro high anyday, at least theres a thunderstorm potential, theres no chance with the azh being the azh.

It's been a valuable friend this summer for most of us. And June was extremely dry – so if it was an "enemy" then as you suggest it wasn't a very worthy one. 

[Captain Shortwave]

Exactly this. Really winds me up. It's really not hard to be unbiased when assessing the NWP or the drivers which may affect the NWP output. My issue was that Downpour said himself that the Azores high was the 'form horse' which means in his opinion, anything other than a rampant Azores high in the output gets instantly disregarded. We just can't have this approach if we're to remain objective.

 

The Azores high (displaced) has only been a major influence in terms of summery weather for the past week or so. The ECM, GFS etc etc all show that the high will pull west slightly over the next 10 days. How far west and the extent of any troughing (if at all) is unknown at this stage. What looks certain however is that some areas will be prone to more cloud than recently as weak disturbances run around the HP system.

 

FWIW here is the latest CFS view for August

 

cfs-4-8-2013.png

Surely it's the case of both sides are just as bad as each other. I've seen many many posts saying that we are going to have cool unsettled weather and that there is no fine weather on the way ever since this current spell was being predicted over 10 days ago. Like the last couple of day I've seen many posts saying that things will turn unsettled with northerly winds, lots of cloud and some rain. All I've seen is the models flipping between two scenarios, one being a scandi trough and north westerly winds the other being a flatter pattern with the jet further north giving more settled weather. Look at the last two GFS runs and the ensemble means for both and that pretty much shows how futile making an accurate forecast beyond Sunday is. The two outputs are completely different.

Edited July 9, 2013 by Captain shortwave

[Downpour]

Exactly this. Really winds me up. It's really not hard to be unbiased when assessing the NWP or the drivers which may affect the NWP output. My issue was that Downpour said himself that the Azores high was the 'form horse' which means in his opinion, anything other than a rampant Azores high in the output gets instantly disregarded. We just can't have this approach if we're to remain objective.

 

The Azores high (displaced) has only been a major influence in terms of summery weather for the past week or so. The ECM, GFS etc etc all show that the high will pull west slightly over the next 10 days. How far west and the extent of any troughing (if at all) is unknown at this stage. What looks certain however is that some areas will be prone to more cloud than recently as weak disturbances run around the HP system.

 

FWIW here is the latest CFS view for August

 

cfs-4-8-2013.png

In the spirit of good grace and fair play I should now probably say that I value your posts and I think you are a brilliant analyst Crewe Cold (particularly in winter) but I think you have over-cooked the breakdown in this case. 

 

As for your accusation that because I think the AH is the form horse I disregard anything that sees it retreat – not true. Just as I wouldn't disregard an uptick in form for a longshot in Gold Cup week just because the favourite had won the last few races.

 

Not every race is to the swift, nor every battle to the strong, but that's the way to bet. 

[phil nw.]

Come on folks let's continue to discuss the charts and not each other.

Some good postings in here today so let's not spoil the thread by going down that road.

 

Thanks all.

[mushymanrob]

re the models struggling mushyIn my view over 90% of the time they 'struggle' as do forecasters to 'nail the exact detail'. Too often folk expect detail such as max/min/rainfall amount/timing (snow in winter) etc etc to be spot on-that is fantasy island expectation really rather than what is often referred to as such at T+ whenever.

 

maybe i used the wrong term john, yeah i know 'nailing down the detail' that far off its almost impossible, its more the likely outcome as a generalisation im on about. some runs hold onto the warm settled weather, others suggest a very cool northerly scourced regime on the back of the expected trough, so quite a variation and as i see it atm its far from certain just which of these two extremes (or more likely somewhere in between) will prove to be closest.

 

It's been a valuable friend this summer for most of us. And June was extremely dry – so if it was an "enemy" then as you suggest it wasn't a very worthy one. 

 

june dry?... not here matey! we had average rainfall and the grass growth atm is still very long and lush. so much so that im not worried about losing work by drought stressed grass this month.

 

after the first week of june, the azh directed atlantic systems straight at us, with breif ridges in between thrown up by the azh... its only this time that its shifted and become our freind.

[Captain Shortwave]

Better run from the GFS with the trough slower and staying further north, but given the output from the GFS and UKMO, the fact they disagree with each other and previous runs, along with the ensembles gives the feeling that there isn't much value to these runs.

 

 

I guess cooler by monday in all locations looks a reasonably safe bet. The models don't seem to know how to handle the speed and movement of systems in North West Europe which will probably result in predicted temperatures fluctuating wildly from run to run

Edited July 9, 2013 by Captain shortwave

[Downpour]

maybe i used the wrong term john, yeah i know 'nailing down the detail' that far off its almost impossible, its more the likely outcome as a generalisation im on about. some runs hold onto the warm settled weather, others suggest a very cool northerly scourced regime on the back of the expected trough, so quite a variation and as i see it atm its far from certain just which of these two extremes (or more likely somewhere in between) will prove to be closest.

 

 

june dry?... not here matey! we had average rainfall and the grass growth atm is still very long and lush. so much so that im not worried about losing work by drought stressed grass this month.

 

after the first week of june, the azh directed atlantic systems straight at us, with breif ridges in between thrown up by the azh... its only this time that its shifted and become our freind.

It's clear from reading your posts that Derbyshire has the wettest, coolest climate in the UK if not on Earth. 

But rainfall nationally was only ~60% of average in June, with an particularly dry picture in the SE quadrant. 

 

http://www.metoffice.gov.uk/climate/uk/anomacts/