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Model Output Discussions 12z 01/06/2017


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36 minutes ago, mb018538 said:

Much as I admire your unabounded optimism and enthusiasm Frosty, if you scroll back to page 94 you've been posting the same chunk of extended GFS showing things setting down every day for a week now! It hasn't got any closer yet :( (this isn't me having a pop, just an observation that we've been led up the garden path a lot this month).

technically this month is only 9 hours 30 minutes old

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An unseasonally wet, cool and windy day amidst an underwhelming week of weather does not a summer make. Much as anticipated through the second half of Spring, the hand-over to Summer sees the atm

There have been some strange observations made today, as too often occurs in this thread whatever the time of year, and largely based on the usual knee-jerk response to longer term suggested NWP.

You always seem to jump in on my posts, along with a few others. Why don't you try giving your assessment of the models instead of picking holes in others efforts!

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46 minutes ago, mb018538 said:

Much as I admire your unabounded optimism and enthusiasm Frosty, if you scroll back to page 94 you've been posting the same chunk of extended GFS showing things setting down every day for a week now! It hasn't got any closer yet :( (this isn't me having a pop, just an observation that we've been led up the garden path a lot this month).

It's got nothing to do with my so called unabounded optimism and enthusiasm, I just adapt to how the models update as the met office do. I don't mind that the fine signal is being delayed, I still think there will be a summery spell, at least across southern UK as we go further into August, towards / during mid month in particular.:)

Edited by Frosty.
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13 hours ago, knocker said:

It is at this point that some amplification occurs with the Azores pushing north in the western Atlantic and the upper trough to the west of Ireland starts to disrupt. Thus by 12z Monday we have a shallow surface low over north west Britain which is phasing in with the low pressure to the south over western Europe. It is how this develops that is creating a certain amount of confusion and interest, This evening the ecm is going with a more organized low which tracks north east into Denmark and southern Sweden over the next 48 hours with indications of a great deal of convective activity

 

Thanks all for the very informative posts Knocker.

I'm a bit confused by the term 'amplication'. Would be grateful if you can explain it. Cheers.

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1 hour ago, mac_ said:

Thanks all for the very informative posts Knocker.

I'm a bit confused by the term 'amplication'. Would be grateful if you can explain it. Cheers.

Put simple it is a pattern dominated by strong ridges and troughs with the upper winds and jet forced into a wave formation, or meridional flow, rather than a straight west- east zonal flow. In the best case scenario it can produce some extreme weather in some areas as the whole.shebang is very slow moving. This isn't the case this morning as the surging of the Azores high pressure, becoming more amplified, in the western Atlantiic is transitional. Thus this is not a good example but just about shows what I mean

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This  might illustrate it better from a week ago over the States.

https://www.facebook.com/amsbogm/posts/10152487042883280

Edited by knocker
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3 hours ago, tempesangel delightch said:

It never started in most parts of Scotland!

And its unlikely to start anytime soon if the Gfs 6z operational run verifies, vile run for the north in particular.

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Actually, things do look like improving next week, especially the midweek period with a window of fine and pleasantly warm weather, particularly across england and wales as high pressure builds in, best weather further south. Then another changeable spell follows from the north-west towards the end of next week but the mid August period sounds largely fine across the southern half of the UK which suggests a north / south split. I think there will be some decent usable summer weather at times during this month, especially across southern britain.:)

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At least with the Atlantic getting blocked off things should improve somewhat with the lighter winds, of course, comes the risk of any showers moving much slower but in any spells of sunshine it will be pleasantly warm

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Edited by Summer Sun
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Rukm1201.gif  Rtavn1201.gif

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Well, UKMO has come up with something more interesting for Sun-Mon in the form of a much weaker low than GFS has been consistently predicting (I know it's the 06z GFS still for some reason but the 12z hasn't changed things much).

Warmer, particularly in terms of the feel of things, but with slow-moving showers meaning a few spots could see more rain than in the GFS version of events - while others see less, of course. 

GEM is still uploading when it comes to the above format but essentially it's halfway between GFS and UKMO on day 5 but then lowers pressure to the SE resulting in a well defined area of low pressure close to our SE that then lifts gradually N, restricting the ability of the Azores High to build in. So not a great effort from that model in the end.

Questions remain over to what extent the AH may pay as a visit starting day 8 or 9. GLAAM is orbiting positive for the first time in quite a while which suggests a better chance of a settled spell - best since early this month in fact - but the C Pac trades continue to pulse stronger from time to time, and there is a strong signal for the MJO to kick off in the Indian Ocean or Indonesia, with the location making a big difference; GFS favours the former which drags GLAAM downward and increases the odds of a changeable W to NW flow returning before long, but other models are more toward the latter with eastward MJO propagation potentially helping us to hang on to ridges for at least a few days at a time.

August certainly has a 'climbing the ladder' feeling in terms of reaching higher standards of weather - with gravity representing that sense that it's harder to get where we want than to fall where we don't.

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For the south of the UK in particular, it looks like a more settled and pleasantly warm spell is on the way later next week as the azores high / ridge builds NE across southern areas according to the latest Gefs 12z mean..so, compared to recently / currently..an improvement looks to be on the way..not just according to this, the met office too.:)

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Well beggars cant be choosers, ecm offers a drying out of sorts as head into next week but really any ridge looks utterly transient in the face of this ridiculously stubborn southerly tracking jetstream, - we just cant seem to catch a break...even by day 10 we can see the azores high being flattened yet again by a series of depressions running SE from Greenland/Iceland.

Think Kevin has posted some stats about 'summer' so far and its not pretty reading if you live in this part of the world, its just getting worse by the day!

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The Ecm 12z also shows an improving picture during the second half of next week, especially for southern UK as high pressure / ridging pushes eastwards across the south bringing a welcome window of fine and warm weather particularly to england and wales, lasting longest across southern / south-east counties..better than a slap in the face with a wet kipper!:D

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Edited by Frosty.
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Tonight's Ecm 12z ensemble mean also paints a better picture during the second half of next week as high pressure ridges eastwards across the south with some welcome respite from the current changeable / unsettled pattern.:)

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Still at least a week of dodgy weather by the looks . Slow moving heavy thundery showers and longer spells of rain at times . Let's hope the high pressure in FI comes closer and closer witch each run 

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Nick Miller on BBC weather for the week ahead saying they're more confident of the Azores high ridging in and settling things down with dry, sunny weather later next week - across the south at least.

Edited by danm
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14 minutes ago, danm said:

Nick Miller on BBC weather for the week ahead saying they're more confident of the Azores high ridging in and settling things down with dry, sunny weather later next week - across the south at least.

yes it looks like the south will benefit the most, im entirely sceptical the north will see much longivity to any settled weather-however, still hoping for the best..

 

 

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ECM looks good this morning, finally some long overdue high pressure and something more settled. Now, how can this one go wrong?! Another low pressure slider over the top? A strong low to suppress the pressure build? Stay tuned to find out!

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The ecm this morning illustrates, IMO of course, how slight adjustments to the orientation of the Azores HP to west effects the onwards evolution.

Because of this Monday's low doesn't track SE over southern England (although a small perturbation does) but instead only reaches norther Scotland before filling and moving NE. Thus the second low doesn't make it around the high pressure and the ridge can consolidate over the UK until Friday when the trough(s) to the north west suppress it bringing strong westerly and rain to Scotland.

Thus apart from Monday and a lesser extent Tuesday next week doesn't look too bad. In fact much of England would hold on to the ridge until the end of the rum albeit temps no great shakes but tending more to average by the end. None of this of this is a done deal next week.

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Edited by knocker
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Much better Ecm 00z in the later frames..and a happy ending!:D

This would bring a long overdue return to summery weather, especially across southern UK..potentially even better beyond day 10!:)

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Edited by Frosty.
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Even at day 10 the ECM NH 850mb picture shows the continued Pacific Block along the Western United States and British Columbia. A remarkable run of high temps in this region. Coastal Vancouver regularly hitting 30 C  and even higher down the coastline in Seattle ( seems this past 3 summers , no longer a maritime climate in this region ). Also of interest the first signs of high Arctic sub freezing and a cooling of a airmass incursion into parts of Siberia. Also a probable cooling down of parts of Southern and Central Europe after the recent prolonged hot spell. As for the British Isles , can only get better ! but no heat wave on that chart.

 C

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An interesting alternative route continues to be advertised by UKMO and with GEM now very similar as opposed to halfway between it and GFS as was the case yesterday.

It would seem to produce a decent day on Monday with near-average temps before either a col (UKMO) or slack easterly (GEM) brings the threat of slow-moving showers but with light winds allowing it to feel very pleasant in sunny spells. Shame there's not likely to be any very warm (let alone hot) air ready to drift across; the slack weekend westerlies have by early Monday pushed maritime air as far as Germany for example.

There are however issues going forward with this hold-up of the low, as it can then quite easily spend a number of days hanging about not far east of us, interfering with the attempts by the Azores High to ridge across us;

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While it's true that GEM is likely getting a bit carried away with the strength of the Atlantic westerly flow on this run, there is a case here for the swift eastward progression of the Mon-Wed low offered by ECM to be the better outcome as far as the longer-term prospects are concerned.

With westerly momentum looking to wax and wane in a periodic fashion over the coming 6-14 days, we just need a bit of luck for a westerly push to displace the Azores High over us, and then a weak westerly interlude to coincide with a trough by the Azores with the high remaining displaced toward us. If only it could play out that simply!

 

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A good looking Gefs 00z mean from later next week, especially for the south with warmer and more settled conditions returning as the Azores high ridges in across southern UK.:)

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The Gefs 6z mean is another step towards a better outlook from around next midweek onwards and especially across southern UK as the Azores high ridges in across the south bringing increasingly settled and warm conditions with plenty of sunshine and lighter winds, at least for england and wales..some fine and warm weather hopefully on the way then!:D

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