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phil nw.

Model Output Discussion 30/06/2012

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A brand new thread to take us into July and in time to discuss the 12Z outputs.

Let`s see if the next few model runs will point to more settled conditions as we go into the second month of the Meterological Summer.

Continue here then.

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Following on from June's topic, and July and set to start on a wet note tomorrow maybe the best day of the week with low pressure starting to dominate again next week

The rain gets going early Monday and it stays

ukprec.pngukprec.png

ukprec.pngukprec.png

ukprec.pngukprec.png

Into week 2 of July and there's no let up its rain, rain and more rain, summer remains firmly on hold

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Indeed S.S. the GFS and UKMO 12z Op runs both show that shallow troughing again over the UK next week.

Here at T96hrs.

http://www.wetterzentrale.de/pics/Rukm961.gif

http://www.wetterzentrale.de/pics/Rtavn961.png

keeping the unsettled and showery theme into the new month-unfortunately a consistent theme of the season so far.

Let`s see if the ECM run agrees when it comes out later.

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I think that the above synopsis from SS may be a little cut and dry and does not take into account the wider pattern. Much of this weeks rainfall will be convective in nature which could lead to a lot of places receiving far better weather than those charts suggest.

We are entering what would appear to be a crossroads after this week.

The ECM and GFS do seem to differ somewhat in the direction of travel in what occurs with the upper trough and this was highlighted by GP in the previous thread. Both are in line with a July phase 2 MJO scenario with no overall upper control with the height of the atmosphere.

The ECM goes for a displacing Azores high option with the trough retreating fully to the North.

post-4523-0-89571900-1341075700_thumb.gi

Meanwhile the GFS is very much sticking with the cut off low and a high pressure bridge further north.

post-4523-0-97566200-1341075801_thumb.pn

So which model is likely to be closer to the truth. The ECM will lead to drier conditions in the south and the opposite is true of the GFS.

Critically, after that, there are numerous permutations of what could occur. I say we get to the middle of this week and see which way we are heading.

I am very much in the camp of that we will see a steadily improving July with a change from a wet outlook with dry interludes to a dry outlook with wet interludes.

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I think that the above synopsis from SS may be a little cut and dry and does not take into account the wider pattern. Much of this weeks rainfall will be convective in nature which could lead to a lot of places receiving far better weather than those charts suggest.

We are entering what would appear to be a crossroads after this week.

The ECM and GFS do seem to differ somewhat in the direction of travel in what occurs with the upper trough and this was highlighted by GP in the previous thread. Both are in line with a July phase 2 MJO scenario with no overall upper control with the height of the atmosphere.

The ECM goes for a displacing Azores high option with the trough retreating fully to the North.

Meanwhile the GFS is very much sticking with the cut off low and a high pressure bridge further north.

So which model is likely to be closer to the truth. The ECM will lead to drier conditions in the south and the opposite is true of the GFS.

Critically, after that, there are numerous permutations of what could occur. I say we get to the middle of this week and see which way we are heading.

I am very much in the camp of that we will see a steadily improving July with a change from a wet outlook with dry interludes to a dry outlook with wet interludes.

I agree with you, as personally I think the week ahead still looks like an improvement from what we had during early-mid June - when deep Atlantic systems brought some very heavy frontal rainfall across much of the UK, as you are all aware.

Ok so Monday and Tues look quite wet, but the rest of the week seems more showery in nature and there will hopefully be some decent sunny spells between showers :) As we progress through next week, then we will have a better idea on which way we are heading for July.

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In my week ahead forecast today I really just went for Monday to be a proper wet day in terms of cloud and persistent rain.

Tuesday onwards I have down as showery and those showery conditions persist until Friday at least. Maybe another spell of general (thundery) rain moving north Wednesday into Thursday?

But much of the time this week I think we're looking at mainly convective rainfall, which means inevitably some places will get a lot of rain and some places will get luckey and have several days of mainly dry weather.

Though really its another geneally pretty uninspiring week in the summer of 2012.

GFS ensemble looks very poor overall;

http://www.wetterzen...chester_ens.png

Time is beginning to tick on now...

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The ECM goes for the stalled/cut off low too

ECM1-120_zbt0.GIF

There could be some longer spells of rain from stalled fronts on this ECM I would imagine, for the south in particular, as well of a lot of showers

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ECM is going for plenty of lows to the south next week

Recm721.gifRecm961.gif

Recm1441.gifRecm1681.gif

Recm2161.gif

The North of Scotland and Northern Ireland could become more settled later next week with high pressure shown to build but for much of england its showers or longer spells of rain

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The ECM is all over the place at the moment,its 12z run has now lurched back to the cut-off low scenario

which is way different to the 00z.

00z.. 12z..

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The ECM is all over the place at the moment,its 12z run has now lurched back to the cut-off low scenario

which is way different to the 00z.

00z.. 12z..

It will have been an outlier this morning tonights ensemble will be out soon

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Interesting to see that gfs and ecm build pressure later in the week, to the north of the uk or even a mid Atlantic ridge. Unfortunately , a rinse and repeat performance of the recent turbulent weather, really bad news for Summer lovers But of course model output has been very illusive of recent days,so perhaps some light at the end of the tunnel or perhaps gold at the end of the rainbow!!!

post-6830-0-31606800-1341085232_thumb.pn

post-6830-0-22161800-1341085267_thumb.pn

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00z ECM operational was pretty close to the ensemble mean.

The 12z ecm looks a bit OTT

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Nothing settled from the ECM ensembles once again the 12z run was an outlier

Recm721.gifRecm1201.gif

Recm1681.gifRecm1921.gif

Recm2401.gif

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Nothing settled from the ECM ensembles once again the 12z run was an outlier

Recm721.gifRecm1201.gif

Recm1681.gifRecm1921.gif

Recm2401.gif

I know that you have been asked this before, but could you please elaborate on these charts, SS. Thanks.

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We are entering what would appear to be a crossroads after this week.

The ECM and GFS do seem to differ somewhat.

I am very much in the camp of that we will see a steadily improving July with a change from a wet outlook with dry interludes to a dry outlook with wet interludes.

http://www.wetterzen...cs/Recm1441.gif

Need something of a big change to get out of the rut of an extremely wet atlantic pattern we`ve been in all June.

Hope your right on that last paragraph,anything like last July would help dry it out.

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The Ecm 12z shows dry and warm weather over the atlantic with the azores/atlantic high ridging northeast but most of the uk is under relatively low pressure and a showery regime but fairly warm and humid for most of the time, possibly something more summery arriving to the far nw of britain later next week but for many it looks like yet more heavy showers and even some strong nely winds possible as low pressure edges further west from scandinavia.

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going back to a post i made this morning whereby i summised that ecm 00z ens mean at day 10 was likely to be closer to verification than naefs, the 12z ecm mean at day 10 now looks much closer to the naefs 00z at the same timescale. not good news if you were hpoing for that azores ridge to make it as far as the uk in ten days time. what the 12z ens does show is that the 12z ecm op was a cool outlier over holland days 9 and 10 so we can presume that the way the op ejects the shortwave ne is unlikely. there is still much uncertainty how next weekend will shape up regarding the placement of the parent low to our north and the diving cut off feature.

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As ever Nick, we are seeing one of those situations where a slight change in the distributions of heights in our neck of the woods leads to a dramatic change in surface conditions.

This often leads to vilification in the models - but if you look at the bigger picture ( like I know you do) that is unnecessary!

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My money is on a Friday LP

It's like a weather fable at present,, stupendous pattern repeat

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Very poor naefs 12z update with a strongish mean jet across n France towards the end of week 2. The last time this was showing at such a timescale was two weeks ago for this upcoming week. Nuff said.

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This chart sums up the week ahead, low pressure in charge with showers and more persistent rain and temps around 19-21c, perhaps a little warmer than that in any prolonged sunshine but the main heat is out of reach across mainland europe although perhaps some of the warmth will flirt with the southeast if the main low is centred far enough west to allow a continental flow to spread up but that is possibly being optimistic. The gfs 00z shows the main low drifting north by next weekend and filling at the same time but pressure across the uk remains moderately low with the ongoing threat of showers even when the low has gone, there is a chance of weak pressure rises across the south and pressure will be high over the near atlantic and across scandinavia but the uk appears to be unlucky with no real sign of an anticyclone filling the void once the main low has moved away..so it looks like another week at least of sunshine and heavy showers with some pockets of warmth but not as warm as it was a few days ago and mainly average temps for most areas as low pressure moves east towards ireland and then further east to sit over the top of the uk for the bulk of next week.

post-4783-0-99422100-1341125561_thumb.pn

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I think that the above synopsis from SS may be a little cut and dry and does not take into account the wider pattern. Much of this weeks rainfall will be convective in nature which could lead to a lot of places receiving far better weather than those charts suggest.

We are entering what would appear to be a crossroads after this week.

The ECM goes for a displacing Azores high option with the trough retreating fully to the North.

post-4523-0-89571900-1341075700_thumb.gi

Meanwhile the GFS is very much sticking with the cut off low and a high pressure bridge further north.

post-4523-0-97566200-1341075801_thumb.pn

So which model is likely to be closer to the truth. The ECM will lead to drier conditions in the south and the opposite is true of the GFS.

Well the ECM has headed towards the GFS this morning with the GFS centering the weak trough further north than previously.

ECM

post-4523-0-31539300-1341129704_thumb.gi

GFS

post-4523-0-93868600-1341129722_thumb.pn

I feel that the better long term solution for settled conditions will be from a cut off trough rather than a weak extension from the northern trough. Any cut off trough should see pressure slowly rise in situ.

With a variety of MJO solutions on offer it is hard to pinpoint where we go next, but those wishing for settled weather will be hoping for phase 3.

post-4523-0-78237600-1341130073_thumb.gi

We are close - but will we be close enough?

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Yet again this morning the main runs models show the UK to be a giant low pressure magnet, seemingly having the strength to suck in depressions from anywhere and making them stick solidly too us. Things look depressingly similar to the way they have looked for weeks now, with any rise of pressure only showing up in FI and even then there appears no inter run consistancy in this evolution, so at least another fortnight of this dross looks inevitable in my opinion. That will take us into week 7 of 13, meaning we will be over half way though Summer and still waiting for Summer to start - hopefully the final 6 weeks will come up with something considerably better, but I won't be holding my breath on that!

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As I mentioned a while back about the weather patterns getting into a rut and remaining in situ for some lengthy period, there seems to be some research that shows a meridional jet flow alludes to this. So here we are going round in circles, so when a change happens lets hope it slaps a HP over us. No signs of that yet and models currently pulling away from positive hints 2 days ago. However that was all FI and thus lets see how this weeks runs develop. Obviously 1st week of July is dead in water re settled warm summer weather.

BFTP

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All the main models (ECM, UKMO, GFS) now go for the stalling cut off low, with the GFS 06z now jumping on board fully also

gfs-0-138_tif8.png

The GEM aslo goes for the limpet low

gem-0-180_iuj9.png

Sunday: Some showers intitally then clouding over in the West by dark with a band of rain moving East, heavy across Western hills at times.

Monday: Quickly following on behind another area of heavier rain spreading up from the SW during the day, this again heavy especially across Western hills with some heavy showers following behind.

Tuesday: Another band of heavier rain and showers moves in from the SW, heaviest across Western hills

Then the following few days sees a showery regime as the low limpets itself near to the British Isles, with some heavy and thundery showers and some longer spells of rain in places

FAX chart showing a succession of fronts crossing the UK

fax60s_wgf2.gif

Rainfall accumulations to noon Wednesday, wettest to the SW

12070412_0106.gif

NAEFS spreads show strong support for the cut off low at +120

naefs-0-0-120_fpx3.png

The end of the run continues to show strong signal for continued unsettled weather into Mid-July

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