Model Output Discussion - 30/6/2014 Onwards - Covering July.

[SteveB]

While it does look like it will turn less settled, it's no were near a write of off.

 

Showers look the order of the day, and temps hold up well right the way through the run.

 

 

 

Sunday looks like an okay day

 

 

Into next week & it's more of the same

 

 

Yes some rain around, but temps staying around or slightly above average for the South of the country, always slightly cooler and wetter the further North you go.

[IDO]

The spread on the 0z GEFS at D7 show where the uncertainty remains:  

 

How far east/west will the trough sits? The outlook of a trough becoming more influential for the majority of the Country rather than the last week or so where a ridge has influenced the weather is now the clearly the main driver.

 

The GEFS have as a whole indicated 5-7 days of a trough driven flow before we look to a N/S split (or SW/NE). This continues this morning. As you would expect the SE/E benefit the most from this setup and as it is early August temps should be above average when the sun is out. Also it could be the case that any fronts burn out time they reach the east so rainfall totals low in favoured areas. ECM for example at D10:

 

 

As for the placement of the trough:

 

GEM has the core low furthest west at D7: 

 

Followed by ECM:   Then GFS the furthest east: 

 

So cross model and inter model disparity as to week 2 remains. Again it is not a change to washout weather just a move away from very warm/hot/high humidity to something more average for most with some areas warm at times (SE) and some areas (NW) cooler and wetter over all.

[Summer Sun]

ECM now starting to hint of a pressure rise towards the end of its run though Scotland and Northern Ireland remain prone to some rain and stronger winds

 

 

GEM hinting at pressure trying to rise as well

 

[knocker]

A quick look at next week and the anomalies on the GFS and ECM and yesterdays NOAA are not a country mile apart. All have an upper low around Iceland with warmer air over Greenland and the very warm air in it's usual position NE Europe. What pans out on the surface is going to be rather dependent on the position of this low but things don't look that bad with around average temps but no significant heat in the pipeline. The Azores high may well push into the south later.

 

[Stormyking]

Latest 12z shows this weekends low not as bad as the 06z, and the rain seems a little less widespread too Friday night into Saturday. 

The low also seems a little further South again.

 

12z

6z

 

Out to 144-150 could actually feel rather warm in the SE, if this comes off, temperatures showing 24-26'c.

 

Looks as though high pressure wants to try and push in from the South West as the run goes, but looking at it I reckon will be just to our Est or wont quite make it as the run goes on further, but could make things feel rather warm and humid again with thundery shower risk increasing again.

Edited July 29, 2014 by Stormyking

[Summer Sun]

UKMO t144 doesn't look too bad certainly the further south you are

 

 

No 850's available yet unfortunately

[IDO]

GEM has now moved much closer to the GFS with respect to the positioning of the trough, a push east. No surprise as it's mean did not support the op this morning. 

 

12z:    0z: 

 

So by T216 cooler uppers stradling the country and a much fresher feel and a lot more unsettled than of late:

 

 GEM at D10: 

 

GFS op tugs and pulls between the trough and block but the former eventually wins out and the westerly flow is established after D10 and we get another GFS classic wet FI:

 

  

 

 

 

This horrible outlook has been showing up in FI every other run now.

 

So GEM and GFS firming up on a prolonged spell of changeable weather for 7 days plus from Friday (all models now very close together) as the trough establishes, though the SE benefiting from a transient ridge around D7-8. The GEFS highlight this is where the uncertainty kicks in:

 

 

That is how far west the upper ridge extend into the SE. The control being in the optimistic cluster:

 

 But again that is only brief.

 

There are signs that once the block to the east eases we MAY (trending) head into an Atlantic spell (GFS), with LP systems and fronts crossing the UK carried through by a rejuvenated jet.

 

 

[Summer Sun]

At t144 UKMO and ECM look to be in decent agreement with the west seeing some rain but more settled for the east

 

[Frosty.]

Tonight's GEFS 12z mean shows a lot of azores high pressure influence for the south and east during the next few weeks with a good deal of fine and very warm weather and only occasional unsettled blips, it's the north west of the uk which looks like having the lions share of the persistent rain interspersed with brighter, showery days and temperatures close to average but with some warmer days here and there. It's a good summer and I think the south / southeast will have a lot more summery weather as we go through august. It's shaping up to be a typical nw / se split with lower heights to the northwest of the BI for much of the time.

 

I'm looking ahead to the autumn and beyond and hoping the coldies will have plenty to cheer about and banish the memories of the rubbish autumn /  winter of 2013 / 14.

[Stormyking]

ECM, looking fairly unsettled on their  latest run by the look of it, rather than the GFS, I dont think it looks quite as warm or thundery either, well going past 192hrs that is.

 

ECM at 216hrs

Not overly warm uppers either

 

GFS however seems to me more thundery and seems to have more warmth mixed in aswell

 Much warmer uppers aswell

 

 

Still far out to say, there does seem to be some disagreement with situation of that low in the Atlantic

[Man With Beard]

I dont think we're any nearer knowing who will be the winner of the Icelandic trough / Euro heights battle for next week. On the face of it, the Atlantic seems to have a lot of energy on the southerly arm of the trough, suggesting regular interruptions through rain-bearimg fronts as long as the main trough is near enough - on some of the ops it is, just about - but tonights NOAA update is a clear shift towards greater heights to our east:

http://www.cpc.noaa.gov/products/predictions/814day/500mb.php.

-which would possibly halt the fronts over the NW. So more runs needed again. Don't put that suncream lotion in the loft just yet!

[johnholmes]

but tonights NOAA update is a clear shift towards greater heights to our east

 

Not sure just what you mean by this rj

If you mean NOAA 8-14 has made a 'clear shift' then this is not true. It has been showing this tendency along with ridging in the contours for about 5 consecutive runs now?

 

my apologies if this is not what the quote I have used above is not what you meant.

 

The UK Met Fax current 120h Fax chart, valid at the moment for Sun 3 August and issued at 2044 this evening also shows the surface high over Scandinavia.

http://www.weathercharts.org/ukmomslp.htm#t120

Of course the fine detail is just how much effect either the upper trough will be having by then, and still shown on the same Fax chart as a weather system affecting the north with a fairly marked surface trough into most of the UK.

 

Their T144h surface chart, (using the same link=scroll to the bottom), shows surface pressure tending to rise at least for the southern half of the UK, with a rather weak ridging effect from the high well east through the Channel and out into Azores region. The north remaining under the influence of surface low pressure and the upper trough.

Edited July 29, 2014 by johnholmes

[knocker]

Can't really add anything to John's post.

 

The anomaly charts tonight are quite similar with the upper low around Iceland.and the warmer air  NE Europe. Depending on the position of the surface low and how far any ridging from the Azores high progresses will define the detail but, as already stated could well be a N/S split. Temps do not look along way from average but could be a little higher in the south.

 

Edited July 29, 2014 by knocker

[Man With Beard]

John

but tonights NOAA update is a clear shift towards greater heights to our east

 

Not sure just what you mean by this rj

If you mean NOAA 8-14 has made a 'clear shift' then this is not true. It has been showing this tendency along with ridging in the contours for about 5 consecutive runs now?

 

my apologies if this is not what the quote I have used above is not what you meant.

 

The UK Met Fax current 120h Fax chart, valid at the moment for Sun 3 August and issued at 2044 this evening also shows the surface high over Scandinavia.

http://www.weathercharts.org/ukmomslp.htm#t120

Of course the fine detail is just how much effect either the upper trough will be having by then, and still shown on the same Fax chart as a weather system affecting the north with a fairly marked surface trough into most of the UK.

 

Their T144h surface chart, (using the same link=scroll to the bottom), shows surface pressure tending to rise at least for the southern half of the UK, with a rather weak ridging effect from the high well east through the Channel and out into Azores region. The north remaining under the influence of surface low pressure and the upper trough.

I think tonight is the first time that the red positive anomoly line has approached the east coast - that's what caught my eye - to be honest all I know about these charts is what I've learnt from your posts so please do let me know if I'm looking at the wrong thing!

[SteveB]

GFS is showing the unsettled weather starting tomorrow.

 

It does look however that the East & South coast may escape the worst of it with Temp in the mid 20's

 

Showers and cooler weather (high teens/low 20's) everywhere else. It does turn unsettled everywhere later next week, but temps still holding up well.

 

 

 

 

Edited July 30, 2014 by SteveB

[IDO]

GEM has moved from the most promising week 2 to the least with LP/trough UK wide so by D8 and D10:

 

   

 

Conversely GFS op now reverting back to its 5-7 day trough driven episode with the core low now slightly to the SW of Iceland and the SE/E now maximising the pressure rise from the Scandi ridge. The pressure chart from the ENS highlights the op is one of the quickest to recover pressure:

 

 

Where as last night's 12z op was one of the slowest. Tentative conclusions that where the low sits at around D5 may drive what happens next. The 0z op goes on to push up the Azores again for a N/S split.  It looks like it is over doing the heights and maybe the Control with a SW to NE split is more likely. The GEFS for the NW show a return to wetter than average accompanied by average temps for those 5-7 days:

 

 London still warm and more showery than frontal: 

 

It is not only GFS struggling with the D5 low conundrum, ECM ENS. from last night show four clusters where recently many suites have had only one cluster at that time period. This will hopefully be resolved in the next 48 hours so we can be more confident of the way ahead. This morning's ECM op is in line with other models as a low sinks south Friday and Saturday, comes up against the block and is sent packing north Sunday:

 

Friday:  Sat:  Sun: 

 

With fronts straddling the country, Saturday: 

 

Again ECM keeps the shallow trough with us for around those 5-7 days.

 

D8:   D9:   

 

UK wide cooler uppers by then from ECM: 

 

ECM not as warm for the SE compared to the GFS mean, e.g. D9: 

 

So next week remains uncertain in detail though the long wave pattern remains trough driven weather.

 

 

Edited July 30, 2014 by i'm dreaming of...

[Summer Sun]

Bar the odd isolated shower in the south and east UKMO shows things becoming drier here with the rain becoming restricted to the north and eventually the far west early next week

 

 

Not as warm as of late but in any sunshine it will feel very pleasant for the time of year

[ThunderBuddy21]

I have no idea what any of this means but is it going to thunder where I am tomorrow?

[Polar Maritime]

I have no idea what any of this means but is it going to thunder where I am tomorrow?

 

Hi TB, Take a look in the convective/storm thread, There's lot's of information for you there http://forum.netweather.tv/topic/80952-storm-convective-discussion-12z-21714/page-22#entry3016032

Edited July 30, 2014 by Polar Maritime

[knocker]

The GFS and ECM 00 anomalies are still much the same with the upper low around Iceland. The detailed surface weather still dependent of the position of the surface low but about average temps seems about right.

 

[Man With Beard]

GFS 06Z for Monday onwards - to the naked eye, for the NW it looks rather average - for the SE though, bar one or two weak fronts ... looking like a reasonable week to be on holiday?? 1020mb always close by, the odd weak ridge nudging in, air sourced from either SW or occasionally off the continent ... a recipe for quite a lot of sunshine (not wall to wall but a reasonable amount), and temperatures - well, I can see 27C being reached more than once in London, East Anglia or north Kent, low to mid 20s elsewhere away from NW?

 

The following chart is ever so slightly cherry-picked but demonstrates my points:

 

Control run even more so:

Of course there were a few charts this morning that veered towards the more unsettled (!)

but I think the models - in general - are trending more towards keeping the upper trough further NW i.e. the GFS solution. Maybe tonights charts will make things clearer.

[Guest HectorTheAwesome]

Some very encouraging signs for yet another heatwave later this summer - bring it on.

 

[Milhouse]

The signs for high pressure to push up from the south is still there, and given recent trends to upgrade high pressure, i wouldnt be surprised if it is reinforced even further. Around midweek theres decent agreement on the 6z ENS mean to bring in something warmer and drier.

 

[Stormyking]

Hmm latest 12 seems alot more unsettled going towards middle range onwards than what the 6z was showing, with more rain and weather fronts moving in, and also doesnt seem as warm either apart from the South East.

12z

 

 

6z

[IDO]

Not much change on the 12z’s so far with the models tweaking the core low in the trough and adjusting the Scandi ridge accordingly. The GEFS show the spread in pressure in London from D5 and by D7 there is about a 10hPa difference within the members:

 

 

Surface conditions will reflect that variety. The GFS op is again a wet one in FI, a recurring theme that I await to either be dismissed or gain ground; no sign of either yet, so FI remains very uncertain. This run breaks down the block to the east slowly and sends Atlantic systems through with some respite for the south as temporary ridge(s) zigzag eastwards.

 

GEM has recently been turbo charged with some sort of upgrade and currently leads SLP 3 day verification. It is similar to this morning, with a trough in charge from D2-10 barring D6-7 where the SE sneaks in a short wave ridge. Interestingly it again runs with the Atlantic storm and it is UK bound at D10:

 

 

Overall the GEM run is showing relatively cool temps for the NW and average to just above in the SE.

 

The GFS op shows some Pacific Tropical Storm potential charting three possible storms in its runs:

 

 

If these arise, then a more meridional flow could return, certainly the Pacific is being modeled to ridge significantly by GFS in response to that mid-latitude disruption. That may push the lower heights to the UK’s side of the NH? 

 

​In the shorter term Saturday looks like a relief for farmers in the SE with front(s) crossing the country and maybe 20mms:

 

 The thunderstorms of late have been a bit of a hit or miss for many so this will be welcome.

 

 

 

Edited July 30, 2014 by i'm dreaming of...