Model Output Discussion 31/07/14 onwards.

[damianslaw]

Models all showing unsettled for the foreseeable future and a pressure pattern we haven't seen for a long long time i.e. the UK locked on the cold side of the trough with heights building to the NW - an unsummery outlook, distinctly chilly for the time of year.

[knocker]

Yup still looking that way on the anomaly charts. Basically dominated by thr Scandinavian trough and the Greenland high, The former is forecast to win at the moment but too early to say it's a done deal but certainly if it progresses that way then distinctly cool weather for most of next week,

 

EDIT

 

Oops just seen JH's post above that rather makes mine surplus to requirements.

Edited August 11, 2014 by knocker

[draztik]

Just to highlight the stark difference between the GEM Op & the ECM Ens at t168

 

 

If the GEM had support from another model, then you may give it a second look. But it has zero support. Binned.

 

Looking to the mid term, and its cool all the way from the ECM Ensembles

 

ECM Height Anom. days 8-13

 

ECM temp anom. days 2-7, 7-12, 10-15

[Captain Shortwave]

Just to highlight the stark difference between the GEM Op & the ECM Ens at t168

 

 

If the GEM had support from another model, then you may give it a second look. But it has zero support. Binned.

 

Looking to the mid term, and its cool all the way from the ECM Ensembles

 

ECM Height Anom. days 8-13

 

ECM temp anom. days 2-7, 7-12, 10-15

No surprise to see the ECM ens back the op up to day 7, doesn't make it right of course.

One question springs to mind is the UKMO. I think that it could get close to the GEM as it's certainly more positive than the ECM/GFS at that timeframe. 

GEM ens

No surprise that it doesn't back the operational, that being said the cold air doesn't get as much as a look in during the weekend and into the following week.

There are many subtleties in the Atlantic region to resolve which will give us the answer to how the things will look over the UK. For example the ECM has a much stronger Azores ridge at day 4 which amplifies north west towards Greenland. This reduces any short term effect of the low in the mid-Atlantic, essentially giving the next system over Iceland a free path to slide east/south east towards the north of the UK.

On the other hand we have the UKMO

The Atlantic ridge is weaker and flatter, this gives the low a better chance of escaping and interacting with the trough downstream

Cooler air from the Arctic gets sucked in towards this low as opposed to heading straight for the UK. Subtle differences which could be the difference between below average and above average temperatures. 

Edited August 11, 2014 by Captain shortwave

[draztik]

I really admire your enthusiasm and optimism for August to happen. Unfortunately the UKMO has been woeful as of late, and the GEM's verification stats at day 6 and beyond see it lagging the others. Putting faith in those models, is fine. But realistically, cool and unsettled is well and truly the form horse. I read headlines in late July suggesting hottest August in 300 years. Now look where we are and what is ahead. Egg on a lot of faces. A lot.

Verification stats day 6

[The PIT]

Looking a bit unsettled this weekend as a low sinks SE. GFS indeed shows a mostly unsettled look from FI onwards more akin to September.

[SteveB]

Yep, Summer has taken an early holiday by the looks of things.

 

Never looking settled for longer than the odd day or two, and temps look un-inspiring.

 

Saturday okay for the South, but not for the North.

 

 

Sunday light showers for mostly the West, but looks usable.

 

 

 

And so it carries on into FI with more of the same.

Edited August 12, 2014 by SteveB

[Polar Maritime]

Yes again the GFS continues with the unsettled/cool theme, Some more very wet/windy weather Model'd for around the 20th as another Low spins in off the Atlantic from a cool N/W feed. Fantastic Winter Synoptic's, With extensive blocking over Greenland and up into the Poles, And the Jet South of the UK. 

 

Edited August 12, 2014 by Polar Maritime

[IDO]

UKMO moved closer to the other main models this morning with a transient ridge for Saturday: 

 

By Sunday & Monday its more in line:    

 

GFS op's turn this morning to blow up the low in week 2: 

 

It remains within the ensembles at around 66% for D8-9. The GFS mean has lower pressure in charge till August 28th, though the south does get some respite now and then.

 

GEM is the most promising for the weekend and early next week (for the SE) and ECM the least.

 

e.g. GEM for Sunday:    ECM same time: 

 

ECM again tries to edge higher pressure in around D8 but again it fails so by D10: 

 

GFS pressure chart shows good agreement on a better day for Saturday, south bias, before lower pressure returns (London): 

 

The UKMO update yesterday for week 2 was in line with the GFS theme and further on till 9th September this continued unsettled for the West and North and the better weather at times for the south. This tied in with the GFS mean signal.

 

FWIW the UKMO Winter LR forecast suggests a 40-80% chance for warmer than average temps for Dec-Feb and the same chance for a wetter than average. 

[phil nw.]

Yes PM they are all showing the same outlook-a cool and showery North westerly through the coming week.

Looking like just a brief improvement towards the end of the week before the next system moves into the north west on Sunday.

The T84hrs fax for Friday going with the raw output with a brief improvement mainly for the south as a transient weak ridge moves in for the weekend.

 

ECM also showing the persistence of the Scandinavian upper trough into next week.

 

so ex Bertha has certainly shook up the Atlantic setup sweeping away our recent warmth with the long lasting heights over Scandinavia gone.

We now see the opposite picture with Mid-Atlantic heights into Greenland changing the upper flow to north of west and the UK now very much on the cooler side of the wave pattern.

 

 

[h2005__uk__]

I see the midnight runs of GEFS and GFS show high pressure building for the bank holiday weekend with temps in the low-mid 20s. GEM has pressure building sooner with temps briefly in the high 20s in the south during next week.

However that's quite a way off and I don't think it ties in generally with what other models are hinting at. Worth keeping an eye on though.

[knocker]

Still looking at next week through the eyes of GEFs an ECM (and NOAA). Not good still. The anomaly charts consistently showing the SW/NE orientation of the Scandinavian trough with the warm air over Greenland. This is basically drawing cold air down from the north leading to well below average temps in the UK. The jet is tracking south to inhibit any interference from the Azores. It really needs a shift east of the main players to change the pattern but one cannot foresee this at the moment.

 

I feel that it's a good thing this set up is occurring now because if it was winter I suspect quite a few members would succumb in their excitement.

 

 

[knocker]

I see the midnight runs of GEFS and GFS show high pressure building for the bank holiday weekend with temps in the low-mid 20s. GEM has pressure building sooner with temps briefly in the high 20s in the south during next week.However that's quite a way off and I don't think it ties in generally with what other models are hinting at. Worth keeping an eye on though.

 

To my untutored eye GEM for next week is not a million miles away from the GFS and the ECM.

[Frosty.]

I would be in full ramp mode and then some if we got charts like these in winter, synoptically stunning wintry charts with reloads of troughs diving southeastwards into norway with high pressure / ridging out in mid atlantic blocking the route of our normal weather..just imagine the -10 -15 T850 hPa flooding south bringing snow showers and sharp frosts...back to reality, and actually, the upcoming weekend does look fine and warm across the south thanks to a weak ridge of high pressure, however,the Ecm 00z op run shows a generally cool / very cool and unsettled outlook with a strong N'ly airflow at times with even a risk of showers turning a touch wintry on the tops of the scottish mountains and a touch of frost in prone locations. I think I will stick my neck out here and say the word autumnal will not be out of place if this run was to verify.

 

In the meantime, here is just a glimpse of what a frosty ramp will look like come late autumn and throughout winter 2014 / 15  

[Polar Maritime]

I have had to delete some post's, Please can we stick to Model Output Discussion only in here.

Many Thanks, PM

Edited August 12, 2014 by Polar Maritime

[Man With Beard]

well last night it looked to me as if weak ridging to the south might switch us onto a more SW trajectory, at least for the weekend - looking at the charts this morning, it looks as if this would be a 3/4 day interruption before the influence of a scandi trough will kick in again, and it is questionable just how far north the temporary change would be felt. Temps could conceivably get up to 25C in the south during this period - significantly more if the GEM has it right - but probably never more than 18-21C further north. Clearly some discrepancies between models still, with ECM keeping ridging down to a 1 or 2 day affair, and GFS puffing up deep lows to the SW.

Further out, the scandi low remains the main player for a while with no clear signs that it will cease to be the case - so coolish, perhaps warmest in the far SW, debatable how wet it will be but there does seem potential for Atlantic lows to drift in from time to time. Also, we have our first proper Greenland High for goodness knows how long - once they appear, they tend to stick around - so odds are firmly against an August heatwave, although never say never as a stalled low to the west can pull heat up from the south - the double trough scenario on NOAA charts (strong scandi trough, minor Atlantic trough) just about allows this idea a sniff of chance - but it could just as easily mean more wet weather for us.

There must be a fair chance of August ending up below average. Did I read somewhere an idea of us being on a 13 month cycle? Would fit 2013/2014 - mainly warm between July 2013 and July 2014 - is August the start of a switch to colder?

Edited August 12, 2014 by rjbw

[knocker]

A brief look through the looking glass at the ECM weeklies.

 

[Summer Sun]

UKMO showing a weak ridge of high pressure building for the start of the weekend

 

 

But things soon turn unsettled and cooler as low pressure returns and centres its self to our east dragging cooler air down from the north a few months down the line we'd be talking about snow but given its August we'll be looking at sunshine and showers away from the north where some heavy and persistent rain is possible with temperatures around or slightly below average for England and Wales but feeling cooler still in Northern Scotland

 

Edited August 12, 2014 by Summer Sun

[summer blizzard]

Tonights GFS and GEM runs are great for cool weather. GFS does go overboard with a stationary front and 13C maxima for me in 8 days..

 

[h2005__uk__]

GEM has [...] temps briefly in the high 20s in the south during next week.

 

The 12z runs have well and truly knocked that on the head!

Edited August 12, 2014 by h2005uk

[Polar Maritime]

Yes we could see our first Frosts up in the Highlands. Also noticeable is the Upper Air over Poles starting to cool as the days get shorter now, And the Polar Vortex firing up.

 

Edited August 12, 2014 by Polar Maritime

[phil nw.]

Yes we could see our first Frosts up in the Highlands.

 

All courtesy of quite an extensive pool of Arctic air coming from the north east.

 

 

quite a notable Siberian/Scandinavian upper trough setting up shop.

Edited August 12, 2014 by phil nw.

[Blessed Weather]

Seems to be a technical problem with the GEM output shown on Netweather tonight? The run is for the period 7th July to 12th July.

Meanwhile, as others have pointed out, the cold upper air is now building in the Artic. Tonight's ECM 12z T850 for Fri 22nd Aug showing the growth of -5c and -10c uppers in that part of the world, and unfortunately for those looking for a return to warmth later in August, the 0c isotherm reaches down to the Shetland Isles.

 

 

[ANYWEATHER]

What is apparent is how cool the uk is shown from both ecm and gfs. in the days ahead. Changeable to unsettled conditions prevail as high pressure is in the wrong place and never gets a foothold over the uk. Of course the charts Im posting at T+240 is fairy land ,and subject to a lot of change. But the main theme is ,don't expect any heatwaves in the nearer future, if anything, this August if the models are right will go down for a notable cool month........

[Frosty.]

Tonight's Ecm 12z op run definately has more in common with early autumn than late summer, it's fair to say we are in for an early taste of autumn during the next 10 days with lots of cool unsettled weather but it's not all bad news. This weekend brings a toppling atlantic ridge southeastwards and it holds across the south on saturday so it should be fine and warm down south / se but then we need to look towards iceland for the next area of low pressure swinging southeastwards into the north of the uk bringing progressively cooler, windier and unsettled weather down across the uk by the end of the weekend and early next week, however, there is a silver lining on this run with the azores anticyclone ridging towards the uk by the end of the run with drier, sunnier and relatively warmer conditions returning. In the meantime it's sunshine and showers, heavy and thundery showers but drying up and brightening up from the west during friday and this process continues into the weekend.

 

We have had a very good summer overall, whatever happens during the next few weeks won't damage it in my opinion, I still think there will be a return to warmer conditions at times beyond T+240 hours, especially across the south. If we have a cold and snowy december / january and then a milder end to the winter I definately will not complain.