Model Output Discussion - 31/8/14 Onwards.

[A.J]

well, I've had a butcher's at the 12s GFS output, and from T0 -T360 it reminds me off the 3 little pigs story with a twist

 

The Atlantic wants to huff and puff and blow our houses down......High pressure replies "No you won't......Jog On little doggy'.........HP Rules

[Cloud 10]

A potential fly in the high pressure ointment being modelled by the 12z  GFS and GEM, with a small low running down the east coast which would be a spoiler for eastern areas for the second half of the weekend.

 

GFS..  GEM..

 

The UKMO having none of it though...

 

 

 

[Yarmy]

A potential fly in the high pressure ointment being modelled by the 12z  GFS and GEM, with a small low running down the east coast which would be a spoiler for eastern areas for the second half of the weekend.

 

GFS..gfs-0-120.png  GEM..gem-0-120.png

 

The UKMO having none of it though...

 

UW120-21.gif

 

On the ECM too...

 

[knocker]

A potential fly in the high pressure ointment being modelled by the 12z  GFS and GEM, with a small low running down the east coast which would be a spoiler for eastern areas for the second half of the weekend.

 

 

 

UW120-21.gif

 

Well the ECM is as mentioned above. Distinctly on the anomaly and on the temps. The evolution from there

Edited September 2, 2014 by knocker

[bluearmy]

Ukmo looks isolated as early as T96 on this shallow upper low. Not sure how much of a surface feature it will turn out to be but this fella has been teasing the NWP since last weekend.

Edited September 2, 2014 by bluearmy

[knocker]

Ukmo looks isolated as early as T96 on this shallow upper low. Not sure his much of a surface feature it will turn out to be but this fella has been teasing the NWP since last weekend.

 

Yes that's an interesting point. Not much at the moment according to the ECM.

[ANYWEATHER]

Well, Well .Well! Gfs and ecm are agreeing on a disturbance during this weekend, no hint of it 24 hrs ago! Given the weak performance from the models as of late, what can we expect next week   :cc_confused:    

[Man With Beard]

Well, Well .Well! Gfs and ecm are agreeing on a disturbance during this weekend, no hint of it 24 hrs ago! Given the weak performance from the models as of late, what can we expect next week   :cc_confused:    

Really bizarre this one. All that High Pressure around and a tiny little low pressure system affecting not more than a couple of hundred miles wide. Impact on the surface? Well it does bring with it a substantial cool-down; till yesterday, most models had this disturbance missing the UK to the west, leaving us in the +8C 850s, but ECM suggests it will now bring us rather chilly +4C 850s at best for some:

BTW Knocker - about earlier today, I did mean the opposite to what I said, never been too good with my lefts and rights

[draztik]

Not very much rain on the GEFS 12z run at all up to 384 hours, any we do have will be relatively showery in nature.

On the CPC NOAA 8-14 dayer it indicates a situation of trough to the sw and high to the ne implying a continental feed of air which may mean very warm conditions for the time of the year, quite similar to what we got in June and July to be precise.

Yep. Ecm ensembles also indicate a scandi ridge & troughing to our SW. And as you say, this is not too dissimilar to what we saw most of summer.

Ecm ens height anom. days 10-15

[knocker]

Still a shallow low on the ECM ens but nought significant on the surface.

 

[Polar Maritime]

The GFS this morning shows the Atlantic returning by around the 14th, With a N/W pm flow out in the run, Spilling much cooler air South over the UK.

 

 

Also the little Low the GFS has been toying with over past few days is Model'd to run across Scotland.. Which will suppress the Temperatures a little up there. 

 

Edited September 3, 2014 by Polar Maritime

[knocker]

Haven't had chance to look at all the models ( no doubt others will correct that omission ) but the ECM doesn't make pretty viewing for the weekend. The upper low is still over the UK bringing a N/S split with reasonable temps, bordering on quite warm,  to the south and distinctly cool in the north.

 

[Polar Maritime]

Yes Knock, A distinct N/S split reg Temps for Saturday.

 

[IDO]

ECM has seemingly now backtracked on it's recurring output of an upper low in the SW region of the UK that flirts with the south of the UK. GFS never really went with this and a couple of days ago introduced the sinking low from the north. BBC weather last night were still going with that old ECM output so I expect all change today.

 

On this morning's ECM that low to the North is slow moving and by Monday it is over the NE: 

 

It i then brushed aside as the higher pressure builds in again: 

 

D6 D10  N/S split.

 

With the current blocked Atlantic, we have low and high pressure systems meandering and interacting and it takes a while for models to pick up the synoptics. GFS by Sunday now has this LP off the Scottish NE coast:

 

So by Monday it has had limited impact: 

 

HP then slowly builds back in: 

 

By D9 it looks like a change from settled weather is still the call as the PV migrates from the Arctic and on this run heads to the UK:

 

The control also agrees on a trough over the UK: 

 

UKMO supports the GFS/ECM re the LP system to the NE and the second push of HP for next week: 

 

GEM is getting there by D7: 

 

But is still sending the LP system further south than the other models.

 

So still a warm few days upcoming. Remaining settled for the south over the weekend into next week but temps turned down a notch or two; closer to average. Rainfall for the south remaining scarce:

 

Next 8 days totals: 

 

This long wave pattern has been a strong signal from GFS for a week or so, as has the cooler second half of the settled period. From mid month it does look like higher pressure takes a step backwards but GEFS have no strong signal yet how unsettled it will turn.

[knocker]

Looking beyond the weekend there is no conformity regarding the anomaly charts. A general summary,  NOAA is sticking with the HP north of the UK whilst GEM and ECM are pushing the ridging further east with greater emphasis on the Greenland trough. GFS is a tad betwixt and between and for a time it had a weak upper trough over the UK but it returns to a ridge with the Atlantic trough orientated N/S. In all it appears to be a bit of a mixed bag and best await for another day I feel before the upper pattern settles.

[Summer Sun]

Sunday and Monday sees a small area of low pressure to our east so winds for a time will be coming down from a northerly direction, fairly cloudy with it some some light rain is possible

 

 

Into next week and high pressure returns settling things down one more

 

[knocker]

The ECM ens isn't being quite so bullish regarding the temps for the weekend PM. The upper low is smack over the UK

 

[knocker]

The GFS has downgraded it's temp forecast and is now very similar to the ECM ens

 

 

[IDO]

Better agreement on the cold pool for the weekend. 

 

GFS on Saturday:   ECM: 

 

Certainly going to be cool for northerners over the weekend with the wind from the north, cloud and rain aligned with low temps from some very unseasonable uppers. GFS accumulated rainfall till midday Sunday:

 

 Temps Sunday: 

 

NB. Some of that rainfall is from Friday's front. Not too bad further south.

 

That upper vortex doesn't clear away till Tuesday now on the GFS:

 

Even by D8 it lingers close to the east, dampening temps on the east coast:

 

Its a weak high straddling the north with a messy upper flow squeezing the high's feed. Again the signal from the GFS of a change continues and at D10:

 

 GEM also hinting at the pressure falling:

 

But the GEFS pressure graph for London shows the scatter in FI and it is clear that lots of uncertainty from around D8:

 

 

Leave the experts to unravel mid-month onwards. The next 7 days or so still promises settled weather for the south Though no real warmth but pleasant enough in the sun.

Edited September 3, 2014 by i'm dreaming of...

[ANYWEATHER]

In all my seven years of model watching, this period now has taken the biscuit! The gfs and ecm are in luny land and to make a decent forecast based on there predictions is impossible. Hopefully we may well see some more reliable output in the near future....well i said hope, its bound to happen!!!

[knocker]

Theere have been indications on the recent anomalies of the HP slipping east and the Greenland trough having more influence. Looking at the NOAA and GFS would perhaps indicate that this is so. The 6-10 day still has the HP firmly north of the UK with little development of the trough. The 8-14 on the other hand has pushed the HP well to the east and has developed the trough to the NW and it is also in good alignment with the isohypes The GFS on the other hand already has the trough well developed but is not so dominant with it in the 8-14 time frame. Be interesting to see how this pans out and whether the ECM follows NOAA.

Edited September 3, 2014 by knocker

[Polar Maritime]

The GFS shows the Atlantic making a return from around the 15th.

 

[Summer Sun]

The GFS shows the Atlantic making a return from around the 15th.

 

 

Early days of course but ECM seems to be going in a similar direction

 

[Polar Maritime]

Yes early days Gav, But it's not the first time the GFS has picked this up. And now as you say the ECM playing with it, A weak signal but Interesting Model watching all the same.

 

Edited September 3, 2014 by Polar Maritime

[Frosty.]

I think the general rule of thumb as we head further into september is for the north west of the uk to be unsettled more often than not but the majority of the uk having a lot of fine weather for the next few weeks, predominantly fine, especially the southeast. The overall pattern looks sluggish, benign with some warm spells of sunshine but with cloudy days, also a risk of patchy rain and under any clear skies at night, a risk of fog patches, nights occasionally chilly but often mild as cloud cover will act as a blanket. 

Edited September 4, 2014 by Polar Maritime
To remove off topic references.