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Model Output Discussions 12z 01/06/2017


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Posted
  • Location: Lincoln, Lincolnshire
  • Location: Lincoln, Lincolnshire

I feel we'll see a repeat of what's happened so far where we get hot weather, breakdown. Then we have a week or so with damp; cool wet weather. Mid month will then no doubt return with some heat again. But who knows : P

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Posted
  • Location: Camborne
  • Location: Camborne

Last night's 6-10 anomalies were dominated by certain essential aspects. A strong N. Pacific ridge (the strongest of the summer h/t MV), low pressure over the Arctic, with a conduit to an upper low in the eastern Atlantis creating a strong thermal gradient in the Atlantic as the Azores HP is suppressed. This aided and abetted by the east European ridge extending into Greenland. I mention this because a couple of spot charts from this morning's gfs output for next Wednesday illustrates this very well

gfs_z500a_nh_24.thumb.png.23b081622c32c42e737f98852b70a577.pnggfs_uv250_nh_24.thumb.png.2147f74da8a4d7558837bc14b9e9d7b5.png

So for a bit more detail. There is moderate rain here at the moment so a the latest fax charts to cover what portends to be a pretty wet couple of days.

PPVA89.thumb.gif.a1919f6cbbc5d6895a1f2eceaf4aef46.gifPPVE89.thumb.gif.9eca453d2375579acae94d92fc210885.gif

The low pressure moves slowly east over the weekend and by midday Monday the UK is in a light northerly as the Azores attempts to ridge in from the south west. It fails to do this and briefly the UK enters a period of a col but the next upper low (see chart above) has entered the fray south of Iceland  The surface features associated with this traverse the country on Wednesday day, aided by perturbations running in from the south west so a fairly wet day. 

gfs_ptype_slp_eur3_15.thumb.png.cabcc1781f2a63fded438635884ac959.pnggfs_ptype_slp_eur3_24.thumb.png.dd155c8a69710a36ef53e4c86380e3ee.png

Again some brief ridging but the main Atlantic low has been tracking ESE and arrives over the Hebrides by 18z Friday bringing with it some brisk westerlies and sporadic rain. This heralds a period when low pressure dominates the eastern Atlantic. So certainly an unsettled period is on the cards but not a complete washout with quite a few sunny periods with the usual N/S bias to some extent. Temps variable around the average.

gfs_ptype_slp_eur3_32.thumb.png.f03ff50c6a6670ff4ea107d16c7ab9db.pnggfs_ptype_slp_eur3_41.thumb.png.70b6475a3cfe3f30820bc21be1f5d80d.png

 

Edited by knocker
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Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
9 hours ago, Scorcher said:

What about 2013? It was excellent. In the Manchester area it was the best summer since 1995 according to weather-history's index. 2014 also very decent.

Those two years must have escaped my attention. Maybe it was all relative as those two years were surrounded by terrible summers. 

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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
44 minutes ago, knocker said:

Although obviously varying in detail the ecm is very much on the same page as the gfs.

ecm_mslp_uv850_natl_7.thumb.png.7406165ad498b3932f3f86ed63231b47.pngecm_t850a_5d_natl_11.thumb.png.db3b3ea7ab725dd4e6c239a3dedc4cd1.png

Look at the amount of northern blocking!!! Wont be any of that come winter....

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Posted
  • Location: Camborne
  • Location: Camborne
22 minutes ago, northwestsnow said:

Look at the amount of northern blocking!!! Wont be any of that come winter....

Assuming I'm guessing correctly on what you mean by northern blocking nws why would this be to your liking in winter? Assume I'm au fait with your preferences

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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
6 minutes ago, knocker said:

Assuming I'm guessing correctly on what you mean by northern blocking nws why would this be to your liking in winter? Assume I'm au fait with your preferences

Yes, i prefer seasonal weather knocker, ie summer warmth/ winter cold, unfortunately in recent times both the above are becoming rarer and rarer, in my backyard at least.:-)

I feared this pattern would take hold once it became apparent the trough was not going to lift out, and i genuinely feel this hideous blocking to the north and the southerly tracking troughs will persist for a good while.:-(4

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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
43 minutes ago, blizzard81 said:

Those two years must have escaped my attention. Maybe it was all relative as those two years were surrounded by terrible summers. 

I'd not include 2014 for heat lovers because of the August but 2013 saw a nice to good June and August with an exceptional July that was every bit as good as many of the hottest months you remember (no rain for 3 weeks, sunny, hot).

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

Scratching around for inspiration this morning ... it may look a bit hopeless but some signals remain on the ensembles that the low coming in for next Wednesday to Friday could be followed by a reasonably decent weekend afterwards. Both GFS and ECM ensembles show the low that follows may dig into the high to our south a bit more some distance from the UK:

EDM1-216.GIF?21-12  gens-21-1-216.png

The ensembles reflect a bit of a split between members which are flatter:

gens-15-1-216.png

and members that dig the next Atlantic low south, leading to a bump of heights ahead:

gens-20-1-216.png

and a few that have a bit of both (brief ridge before Atlantic breakthrough once more)

gens-5-1-216.png

So unsettled is still the main theme, but not completely hopeless for good weather and still that small chance that summer could return rather faster than expected

 

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Posted
  • Location: Brighton (currently)
  • Location: Brighton (currently)
10 minutes ago, northwestsnow said:

Yes, i prefer seasonal weather knocker, ie summer warmth/ winter cold, unfortunately in recent times both the above are becoming rarer and rarer, in my backyard at least.:-)

I feared this pattern would take hold once it became apparent the trough was not going to lift out, and i genuinely feel this hideous blocking to the north and the southerly tracking troughs will persist for a good while.:-(4

I wonder if the southerly tracking jet is at least partially a result of the quiet sun. There is also the failure of the el nino to launch and quite a cooling is currently taking place in central tropical pacific.

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Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby
12 hours ago, blizzard81 said:

Some drama queen over reaction on here tonight with regards to next week's weather. The first half of next week doesn't look too bad at all. I would sort of understand this reaction if we had experienced some decent summers in the last 10 years or so. The fact remains that we haven't had a decent summer since 2006. This is the new norm by the looks of it. 

when i first joined here, the 'new norm' or 'large teapot' was a term used to describe the run on milder winters , snowless for many, that typified winters 97-07. then we had a run of winters with cold snowy spells including 2010 and spring 2013.

imho its only a question of time before we get another run of clasic hot summers, and despite the early hints this year would be it, it wont be. the anomaly charts all seem to suggest a large deep upper trough driving our weather from later next week . that will be hard to shift, right at a time we were looking for high pressure domination. a strong southerly tracking jet and a mean upper flow north of west surely is something to frustrate heat seekers at this time of the year.

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Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby
12 hours ago, Scorcher said:

What about 2013? It was excellent. In the Manchester area it was the best summer since 1995 according to weather-history's index. 2014 also very decent.

2013 was good for the south and west.... not so for eastern and central areas. we had a cool overcast weekend, and several other days too, when most of the south and west were baking.

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Posted
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.

Just model 'output' discussion please in here,Ta ☺

 

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Posted
  • Location: East Ham, London
  • Location: East Ham, London

Afternoon all :)

A rare summer visit for me into the model output area.

In lowland East London, it's been a decent summer thus far but the overriding theme has been the continuation of the long dry spell which has gone on since last autumn. A couple of decent warm/hot spells and overall pleasant (and I understand how frustrating it has been for points further north) but the lack of prolonged rainfall has been the main story.

Looking toward the end of the month it's not a good picture for those wanting heat though (and again with my IMBY hat on) it's hardly a washout and there are days with transient ridges which, if you're lucky, could be very pleasant.

The GFS 00Z OP at T+240:

gfs-0-240.png

A weak ridge of HP for the south but a cool WNW'ly flow and heights to the far NW though the Atlantic has perhaps slowed a fraction.

ECM 00Z OP at the same time:

ECM1-240.GIF?21-12

Not hugely different though the Azores HP is more pronounced suggesting a longer window of fair weather before the next Atlantic incursion.

GFS 06Z OP at T+234:

gfs-0-234.png?6

Perhaps the jet tracking back north a fraction ? The flow is still sourced from Labrador so nothing warm I'm afraid though as usual in these set ups the south fares better than the north.

Tracking back through the 00Z Ensembles at T+240 and it's the lack of variation that is the most striking. There are nuances on the exact placement of the jet but only one tries to build a weak HP to the east and all the rest have Atlantic control in one form or another and some Members are worse in terms of weather for the British Isles than the OP (the Control for one) with the jet even further south.

It's going to be a disappointing ten to fourteen days I fear for those wanting heat but with the whole of August to come far too early to be disheartened. Upstream and other events may work more in our favour with time but I fear our old friend Patience will be paying an extended visit.

 

 

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Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK

Rmgfs144sum.gif

In a word: wet

Much of central Europe is looking very soggy over the next week to be honest.

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North
24 minutes ago, mb018538 said:

Rmgfs144sum.gif

In a word: wet

Much of central Europe is looking very soggy over the next week to be honest.

Looking on the bright side, a summer 2017 drought is unlikely :D

What we are seeing from the models is typical British changeable weather.

Edited by Frosty.
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Posted
  • Location: Hanley, Stoke-on-trent
  • Location: Hanley, Stoke-on-trent
8 minutes ago, Tamara said:

The queue of centrally initiated bursts of Nina like easterly winds in the Pacific have contrived to wreck hopes of that last third of July sustained improvement. As attempted to explain about a week back, a bluff had been called in terms of the models catching on that the surge in atmospheric angular momentum from the extra tropics was not going to get support from the eastward progression of tropical convection ...and corrected accordingly in the face of another surge of trade winds across the central Pacific. 

The coming 10 days or so certainly look disappointing, especially in view of what had been anticipated.  The supressed Azores signature downstream is c/o of an inflated Pacific high pressure anomaly (a product of the easterly trades) working destructively downstream in terms of dictating the wavelength of the pattern and preventing eastward ridging of the AZH to deflect low pressure away NE'wards - and instead they are being steered from W to E closer to or over the UK

 The problem with longer term sustainability of this de facto Nina signal, is that despite the correction in angular momentum tendency which ended this weeks attempted Western European ridge inducing plume, total angular momentum remains close to parity. What this means is that with no true global Nina feedback in place, there will be high sensitivity to further sudden shifts in angular momentum tendency as soon as the easterly trade wind signal in the Pacific lets up. Ergo: a lot more model volatility and the true possibility of better charts at sudden notice (beyond the upcoming 5 to 10 day period)

Deterministic MJO modelling has been starting to show more traction finally in wanting to propagate the tropical convection signal eastward - which brings it into a direct conflict with any persisting easterly trades - and something has to give...

The glass half empty inference is that persisting Pacific easterlies would stone wall progression of tropical convection, and yet another drop back in angular momentum tendency would occur and our unsettled downstream pattern persist through the opening 5 to 10 days of August

If we take a look at the two week VP200 signal, the support for the current pattern stranglehold is well advertised by the distinct Pacific easterly wind (orange)anomaly close to the dateline, creating wind shear and unfavourable for progression of the blue convection anomalies over Indonesia

twc_globe_mjo_vp200.png.

The current strength of these trades is reflected by the Southern Oscillation Index tanked in distinctly positive territory reflecting the high pressure differential in the Pacific and the subsequent absence of convection cloud top cover close to the dateline

https://www.longpaddock.qld.gov.au/seasonalclimateoutlook/southernoscillationindex/

This signal starts to weaken during week 2 with the the easterly trade winds tropical supression replaced by a more convectively active signal and increase in westerly wind inertia being able to invade from upstream. Increased westerly wind inertia = rising AAM tendency and increased chances for downstream Western European ridges.

The clue to recovery is that, despite the localised Nina forcing, the Global Wind Oscillation orbit is not reflecting a true Nina global signal and with the atmospheric state closely aligned with the ENSO neutral base state.  A sudden collapse of the fax Nina Pacific pattern would infer a relaxation of the supressed grip on the Azores High and a return to better summer weather from the south west

I'm not keen on the complete accuracy of this GEFS product for forecasting GWO, and much prefer tropical and extra tropical real time data - but it will suffice to support the notion of underlying relative stability of angular momentum around parity. With low AAM bias taken into consideration with this product, not a great amount of downside there considering the present destructive forcing on the Pacific

gfsgwo_1.png

As for any suggestion of northern blocking adding to supress the jet stream and leak anomalously cool air southwards to mid latitudes - whatever any NWP output may try to suggest at any time, not sure how this is going to happen with a cold stratosphere>troposphere profile that continues to point to a solid +AO.

time_pres_HGT_ANOM_JAS_NH_2017.png

 

So taking into account all this and the above stand-off which doesn't have fundamental long term support much beyond 10 days +, I think the closer we get to the turn of the month, yet another bluff is going to be called on the models in terms of seemingly churning out endless flat zonally orientated charts

Despite some mundane weather to greet the start of family school holidays, whatever happens this will be interesting to watch play out.

Your attempts to cheer us up with some solid science are much appreciated Tamara! Any hope that can be offered to those of us who would like even a 7 day settled period is welcome, in a "model world" where hope is extinguished 6 hourly.

Edited by davehsug
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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North
16 minutes ago, davehsug said:

Your attempts to cheer us up with some solid science are much appreciated Tamara! Any hope that can be offered to those of us who would like even a 7 day settled period is welcome, in a "model world" where hope is extinguished 6 hourly.

Here Here, thank goodness we have Tamara, always a joy to read. As for the outlook, in a nutshell it's changeable with some rain, some wind, some cool days / nights and some pleasantly warm sunshine. :- )

Edited by Frosty.
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Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts

Dipping in and out as I am wont to do over the summer, I am struck my how much the mood in here has been going from supreme optimism to borderline despair on a regular basis over these past two months. And of course this is the result of what the models are showing for one three-four day period compared to what they start showing in the next three four day period.

That seems to be the pattern of this summer.... the models swaying too much in line with one signal and too far back in response to a counter signal.

My time off work this summer is 10th to 25th August and I'm hoping to get to the Bristol balloon festival as a spectator in some really benign conditions. Far too early to see anything on the models for that timeline, but I'm guessing no pattern that develops this summer will have any 'stickability" except the pattern that sees us the good week, not so good week mode  (for us Southerners anyway).  Despite the current pessimism I remain confident that we will see outbreaks of really decent weather during the next six weeks or so... and I would not be surprised to see modelling of that that exceptional night time heat shown by GFS a few days ago, pop back up again.  So I'm relatively confident that I will enjoy a fair bit of my holiday time as far as the weather goes.

BUT...as I type....I'm suddenly mindful of the time of year we are out....the schools breaking up.  I'm sure it wasn't that long ago that we were enjoying a mighty fine summer which went rapidly downhill as soon as the school holidays started. And it's not the only time I remember a shift in the preceding weather pattern  of the summer.  So I'm crossing my fingers that this isn't one of those redefining changes we are now undergoing, but a continuation of the pattern of summer to this point...which from my backyard has been usually pretty good without being consistently so .

 

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Posted
  • Location: Camborne
  • Location: Camborne

A small digression from the models, I know quite, quite, wicked, but faint heart, etc. Just to show the Valentia midday ascent in the cooler air in the SW quadrant of the low and very close to the occlusion.

2017072112.03953.skewt_parc.thumb.gif.751fbd3fc3e60b28800c20786f440df2.gifPPVA89.thumb.gif.4aafc922cc02a6338da6a689bd5be634.gif

Not sure what to make of the kink at 775mb

2017072112.03953.stuve700_parc.thumb.gif.03cec18a9ad3d08e1be44ac46c516d99.gif

Edited by knocker
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Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK

Big differences again tonight - UKMO is nowhere near as unsettled, keeping the low further west.....GFS is low pressure until the end.

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

12Z runs... where did the jet go?? Models have suddenly decided to take all the sting out of incoming low next week.

The result is divisive. The GFS 12Z is a bit like scratching your nails down a blackboard (hurts just thinking about it!), with yet another trough getting stuck over the UK by the end of next week. The GEM also gets the trough stuck, but this time next to NW Scotland so not much better. So that leaves the UKMO to fly the flag of hope ... and I have a sneaky feeling this one would stall the trough much further to our west ... which would be interesting to say the least:

UW144-21.GIF?21-18 

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Posted
  • Location: Camborne
  • Location: Camborne
25 minutes ago, Man With Beard said:

12Z runs... where did the jet go?? Models have suddenly decided to take all the sting out of incoming low next week.

 

 

Here maybe?

gfs_uv250_natl_23.thumb.png.1c8d0747bf37b0a51bb47c419a1175cc.pnggfs_z500a_natl_23.thumb.png.e42f62c8781a730f6e939cf3332e2208.pnggfs_ptype_slp_eur3_22.thumb.png.bbe5ab883488f16699c2c2fa373b366f.png

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

Perhaps if ridging into Greenland is encouraged and a very slack pressure area north of the UK (as before this year) with the trough stretching south it might weaken and push the jet a tad further south and perhaps encourage a break away upper low to swing south east in the direction of Iberia and open up some interesting possibilities :shok:

Just saying!

.gefs_z500a_5d_nh_53.thumb.png.a84300c5275d4c7e5364457ae73e9118.png

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