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Model Output Discussions 12z 01/09/2016

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A new thread then as we enter the first month of meteorological Autumn.

The warm and quite dry weather of the last few days looks like being interrupted as we see low pressure and fronts moving in over the weekend with some rain about for many.

sat.gif

As we go into next week though we look like returning to some quite warm and fine conditions as pressure rises across the UK and the continent.We can see this trend starting on Monday -from the 006hrs GFS

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Looking further ahead out to day 10 on the Ens means,and they look pretty good with High pressure just to our east and the Atlantic trough out west and the wind flow from a warm south/south  westerly direction.

Areas towards the far north west seeing the most effect any Atlantic incursions with many locations further south looking again at quite low rainfall totals- after the weekend blip.

day 10.pngday 10 ecm.png

and the London 2m temperature/rainfall ens graphs

sep1.giflonsep1.gif

Let's see if this trend continues as we await the evenings model runs.:)

 

 

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Well both the ECM and GFS are variations on a theme of each other, showing the unsettled interlude over this weekend, Monday being the improvement day, then a few warm/hot sunny days next week with increasing thunder risk before the Atlantic moves in again towards the end of the week. One could say, something for everyone.

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18 minutes ago, MP-R said:

Well both the ECM and GFS are variations on a theme of each other, showing the unsettled interlude over this weekend, Monday being the improvement day, then a few warm/hot sunny days next week with increasing thunder risk before the Atlantic moves in again towards the end of the week. One could say, something for everyone.

Agree,no heatwave on the cards as of yet,time will tell though,its happened before so who knows! Those hot days i feel will be tempered down in the next few few days. Or could i just be kidding myself again?

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3 minutes ago, markyo said:

Agree,no heatwave on the cards as of yet,time will tell though,its happened before so who knows! Those hot days i feel will be tempered down in the next few few days. Or could i just be kidding myself again?

Personally I wouldn't big up or play down anything just yet. It looks like the 10C isotherm safely makes it way over the UK, which in any sunny conditions will allow temperatures to rise comfortably to 24-27C at least. If the 15C gets this far north then, again in any shine, 27-32C is still achievable in early September. All to play for in my opinion. You will of course need more of a push to get heat up there but it's certainly not out of the question just yet. 

12Z rolling out soon so will be interesting to see what it heralds.

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51 minutes ago, MP-R said:

Personally I wouldn't big up or play down anything just yet. It looks like the 10C isotherm safely makes it way over the UK, which in any sunny conditions will allow temperatures to rise comfortably to 24-27C at least. If the 15C gets this far north then, again in any shine, 27-32C is still achievable in early September. All to play for in my opinion. You will of course need more of a push to get heat up there but it's certainly not out of the question just yet. 

12Z rolling out soon so will be interesting to see what it heralds.

Take your point,very well put. We will see,close call i feel but 12Z should prove interesting, 

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Still looking hunky dory on this evening's GFS

It's still running with cut off upper low at the end of the week that facilitates a shallow low pressure feature running NE into the UK which could bring some hot temps to the SE for a short time. After that HP service is resumed and merely a matter of how much will the Atlantic systems impact the north.

gfs_z500a_natl_32.pnggfs_t850_nh_natl_37.png

 

Edited by knocker
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1 hour ago, Matthew Wilson said:

Hello high pressure. All I can say is this is really what it's all about. Low pressure swinging towards Greenland, high pressure building over the Uk Monday, Tuesday, Wednesday from the ECM. Long may it last! For weeks hopefully:D

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Nice Charts  heres the latest!

adam.png

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air-fan-smiley-emoticon.gif

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I'm starting to wonder just how resilient that Scandi High could end up being. Could it rule over any attempts by low pressure to move up from Iberia?

The model output has be thinking of a stunning spell of weather five years ago, but looking at the charts, it's clear that an Iberian low did not feature. Amazing the extent of heat import we achieved using the anticyclonic circulation alone;

Rrea00120110929.gif Rrea00120110930.gif Rrea00220110930.gif

Walking along the beach in Christchurch with the air temp in the high 20s yet the sun not very high in the sky... one of my most treasured weather memories. 

Anyway, enough misty-eyed reminiscing. It does appear that next week we'll have the more common setup in which, for numerous days of sparkling sunshine, we are dependent on the Atlantic jet having nothing to do with the shallow lows developing in the hot air over Spain. GFS has leaped enthusiastically toward this idea on the 12z after an alarmingly progressive 06z, but ECM is less keen - though not as much so as it was this morning. 

Once the low starts edging nearer, the odds of seeing areas of cloud exported from continental storms increase steadily. Last week here served to remind me of that all too plainly, although it was not a textbook example as the upper-level flow was more toward the SW than S.

The significance of next week's potential warmth becomes very apparent when plugging in raw GFS 2m temp. values against the LTA; the month-to-date anomaly could be near +2.5*C for many parts of England by next weekend. That's without adjusting for the locally under-cooked maximums that are typical of the model.

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Certainly temperatures look to continue above average quite widely next week.The peak +ve anomalies according to the GEFs look to be around days 5-7.

temp..png

up to 4c above average in places-not bad!

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Today

Cloudy with patchy rain in many areas and windy with heavy showers in NW Scotland

ens_max1hrprecip_20.pngens_max2mtemp_22.pngens_mean1hrprecip_43.png

Looking at the GFS this morning indicates that next week still isn't nailed down by a long chalk.

Wednesday sees the negatively tilted upper trough orientated to the W/SW of the UK. All well and good with the UK in a warm southerly flow with the HP to the east. But subsequently not so good with some increase of amplification and an Omega block in the wrong place with ridging over the Baltic. This allows frontal systems to track east from the Atlantic before HP ridges NE again. But by T240 another TC has emerged from the east coast of the U.S. to engage the 500mb pattern so this is best left.

gfs_z500a_natl_24.pnggfs_6hr_precip_eur3_24.png

gfs_z500a_natl_32.pnggfs_6hr_precip_eur3_35.png

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ECM looks broadly similar - though the theme of taking the very high 850s down continues. A quick glance from the 15c line, but mostly 850s just over 10c - which will probably mean 26 or maybe 27c in a favoured spot. Still very, very good for the second week of September.

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The ecm has a not dissimilar upper pattern on 00z Wednesday with the cut off upper low to the WSW with the UK in the SE circulation of the HP to the east and warm temps over the UK. Subsequently the upper trough tracks east and surface fronts reach the UK by the weekend. It's all becoming a tad mobile.

 

ecm_mslp_uv850_natl_9.png

Edited by knocker
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The models really can't get a handle on where and to what extent a closed low develops along the trailing frontal boundary near the Azores early next week.

The further north and/or deeper the low, the faster it's likely to make an escape north and - it currently appears - deliver a glancing blow to the UK - (rain restricted mostly to western fringes) which allows the plume to hang on but in diluted form. So we go from very warm to pleasantly warm, or thereabouts.

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Certainly would appear a move from the ops back to the pattern of the last six weeks - a decent Monday, Tuesday, Wednesday, then Thursday increasingly iffy, Friday the lull before unsettled weather returns for the weekend! Strange how the weather has moved with the weeks recently!

ECM1-144.GIF?02-12  UW144-21.GIF?02-07  gfs-0-144.png

Would appear to be good agreement - for once! It may, of course, be another instance of the ops being over progressive with the Atlantic incursion, since the ensembles generally stall the Atlantic trough for longer - leaving us pretty warm (though no route for the severe heat in Spain/Portugal to get to us except on one or two ensembles, that one is nearly off the table now).

gens-21-1-144.png   EDM1-168.GIF?01-0

so talk of an unsettled end to the week still be a little premature

edit latest ECM - still slower to push the heat away, even by next Friday

EDM0-168.GIF?02-12

 

Edited by Man With Beard
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2 hours ago, Man With Beard said:

 

   

  

so talk of an unsettled end to the week still be a little premature

edit latest ECM - still slower to push the heat away, even by next Friday

 

 

You are a wag MWB since you have been waxing lyrical about searing heat for days now/ :) h by the way the ecm has max temp of 22C for Friday. :whistling:

Anyway the EPS this morning has the Omega Block just a tad too far east resulting in the trough nudging in with the upper flow veering from SWS to SW. Ergo systems will edge in but at this stage it would be foolhardy to to rule out the surface high to be close enough to keep the UK within it's circulation and keep any fronts at bay

ecm_eps_z500a_natl_9.png

Edited by knocker
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Euro this morning restricts the real heat to Tuesday-Wednesday which is positive for those wanting Autumn to get going. 

 

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Long way off but next weekend could see a battle developing between high pressure to the east and low pressure to the west

Rtavn1921.gifRtavn2161.gif

Temps in the mid to upper 20's for the SE next weekend if that came off

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3 hours ago, knocker said:

You are a wag MWB since you have been waxing lyrical about searing heat for days now/ :) h by the way the ecm has max temp of 22C for Friday. :whistling:

Yes it would seem the plume got away this time ... Or has it?????

gens-5-0-132.png   gens-12-0-132.png

I would say chances of getting 30C plus next week were probably 25% yesterday, and now 10% today - but the chance is still just about there. Though you may have trouble sleeping in Camborne for a couple of nights!

22C for where, by the way?

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13 minutes ago, Man With Beard said:

 

  

 

22C for where, by the way?

Spaldng.

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Usual GEFS scenario midweek with the southerly drift. Moving on it's difficult to see any Atlantic fronts making any major headway east, a bit depends on where the surface HP sets up, and the signs are for HP continuing to be the major influence well into the 14 day period.

gefs_z500a_nh_25.pnggefs_z500a_nh_37.png

Edited by knocker
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Interesting to see signs of steadfast blocking to our NE so early in the season. There is a hypothesis that the anomalously low sea ice in Barents/Kara could help with blocking over Scandi, but that might not be relevant until late autumn and early winter.

Whatever the case, a standoff could keep us on the warm side for some time to come. The 12z GFS has us strolling through a great number of warm afternoons until some two weeks from now.

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