Model Output Discussion 18z 28/07/13

[Frosty.]

Even though the Gfs 12z has really stung the north atlantic into life, high pressure still manages to bring a few settled spells towards the last 7-10 days of september to the southeastern half of england at least, so if this run has over egged the atlantic, the outlook could still be much better for more of the uk, it's still all to play for IMO.

Edited September 10, 2013 by Frosty.

[draztik]

the GEM wants to drag back summer @240

Edited September 10, 2013 by draztik

[No Balls Like Snow Balls]

The pressure ensemble on the GFS12Z shows the op run was at the top end of the pile (not quite outlier)

 

 

Maybe suggest's the LP could still end up further South than what the op shows.

Fully expect the 00Z to take the LP on a different route such is the nature of trying to nail down the track of LP's

Edited September 10, 2013 by No balls like Snow Balls

[Frosty.]

the GEM wants to drag back summer @240

Some of the Gfs 12z charts I posted above look better than that with a high pressure cell centred to the southeast of the uk, that chart you posted looks relatively poor with a lot of cloud and a moist wsw'ly breeze.

[Summer Sun]

Unless there are any downgrade in the next 72 hours we are on course for the first storm of Autumn but not from the Atlantic

 

[Summer Sun]

Its going to be very windy for some exposed part in the north early next week by the looks of it severe Gales look very possible at the moment

 

 

By Tuesday it continues its track down the east

 

 

Its not in any hurry to leave the East which is going against the met office outlook

 

Edited September 10, 2013 by Summer Sun

[Man With Beard]

Yes this is what I thought was happening, last night's ECM stopped me being too confident but now it seems clear to me that the settled picture of the last few months is going to retreat a little, I now expect pattern of autumn depressions sweeping in interspaced with the odd dry day or two - I know some output goes for a settled end of the month but I just have a feeling that once the Atlantic (or in this case, Icelandic?) train gets in, it will be around for more than a week. Both ECM and UKMO agreed on this storm tonight and I always believe that when ECM and UKMO are in agreement, it's pretty likely to happen:

[Frosty.]

There is something for everyone on the Gfs 12z run, a Northerly blast and then a reload for scotland and some warm spells for the south & east later, the british climate is very interesting, there could be mountain snow next week in scotland and later in september, the southeast of the uk could be in a summery 24 celsius with the BBQ out.

[Captain Shortwave]

Significant blocking high developing over Russia which pretty much causes the low to limpet over the North sea

Day 10 would see the next low approaching and it only has one way to go

 

Edited September 10, 2013 by Captain shortwave

[Frosty.]

As well as new mobile friendly model viewers, we have also added the GEM to the site today (limited chart types at the mo, but more to come). 

 

You can view the various models from here:

http://www.netweather.tv/index.cgi?action=charts-and-data;sess=

the new design is fantastic, great job by paul and the team.

[Frosty.]

With most of the focus on the upcoming very cool, windy and wet spell (especially for the north of the uk) the further outlook continues to trend more anticyclonic with benign, warm and sunny weather with overnight fog, at least for the southern half of the uk, the Gefs 12z mean also hints at a trough to the northwest digging southwards and drawing much warmer continental air northwards in the process towards the end of the month.

Edited September 10, 2013 by Frosty.

[ANYWEATHER]

Pointless, looking past the weekend , but the charts still scream some very autumn like charts! A big cool down is likely from the weekend onwards, and perhaps the first snows for the Scottish Mountains, Whatever way you view it, this September is different from a good few in the past...  

[Summer Sun]

Here is the latest from Gibby on the models this evening

 

Good evening. Here is the report on the outputs of GFS, UKMO, GEM, NAVGEM and ECM for tonight Tuesday September 10th 2013.

 

All models show a changeable pattern for all areas between now and Sunday with a series of troughs sliding SE and East over the UK over the next three or four days bringing spells of showery rain to all areas at times. The South will see the most prolonged if not the heaviest rainfall with only Saturday offering something rather drier later in the day. By Sunday all models show a vigorous depression developing to the North of Scotland with winds becoming strong to gale over most areas later in the day with spells of heavy and persistent rain possible.

 

GFS then shows a cold front swinging SE over the UK with clearer, cool and showery conditions for a few days before less cool and drier conditions affect the South by midweek. However, the pattern remains changeable with further Low pressure crossing East close to the North of Scotland with further cloud and occasional rain. Later on a ridge of High pressure affects the South with fine and dry conditions likely while the North sees a westerly flow with cloud and some rain. At the very end of the run an ex tropical storm winds up close to NW Ireland with attendant fronts crossing the UK with rain and strong winds, the latter chiefly towards the NW.

 

The GFS Ensembles show fairly average uppers when taken as a whole made up from members offering conflicting resolutions. The operational is a very warm outlier on the eastern flank of the ex tropical storm at the end of the run. Rainfall is not shown to be anything noteworthy beyond this weekends and the start of next week's storm.

 

The Jet Stream shows the flow digging SSW across the UK tomorrow in association with the complex frontal system of tomorrow. The flow weakens away from the UK back to a position to the North of the UK. In association with the deep Low to the NE early next week the flow dives SE strongly over the UK from a punchy flow across the Atlantic spawning further Low pressure later next week.

 

UKMO tonight shows a deep low pressure area slipping SE towards Northern Scotland next Monday with rain and strong winds having cross the UK followed by distinctly cool and blustery NW winds and squally showers the order of the day for several days early next week.

 

GEM tonight shows a very unsettled and windy start to next week with rain followed by showers before a slow relaxation of conditions allows High pressure back into Southern Britain at least towards the end of the run.

 

NAVGEM shows a cold and unsettled start to next week with Low pressure sliding SE down the North Sea with a very windy and showery NW flow with hail and thunder in the showers for many.

 

ECM tonight shows a very disturbed and cool start to next week too bringing Low pressure as NAVGEM down the North Sea where it fills and is responsible for delivering the UK cold and showery weather with NW winds veering towards the NEW by midweek. Pressure does rise as the Low fills up soon after midweek with a slacker pressure pattern though with disturbed air aloft showers would still be likely. Then at the end of the run it does look like Low pressure is liable to feed back down from the NW.

 

In Summary tonight the weather looks like becoming quite volatile for a time at least at the start of next week as a deep Low is more or less confirmed now to move down close to Northern Scotland from the NW late in the weekend. Heavy rain then cold showers would be experienced for all if any of tonight's output verifies. Later in the run the pattern remains a little more confusing though there seems a growing trend to hold Low pressure close by or bring new centres into play come mid or late week next week with further rain or showers possible. All in all there is a lot of Autumn in the output tonight with something for everyone possible in the next 10-14 days.

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

[Frosty.]

Cor blimey that update from gibby sounds unsettled.

[bluearmy]

Naefs 12z not trended further away from the possible height rise last third sept. cpc 8/14 looks interesting with a weak upper ridge supporting any anomoly. no confidence now with the fi ens suites lacking consistency in latter stages. Lets hope the 00z was indeed the 'rum' run and the promise of something settled to follow what now looks a very deep trough to our east next week.

[draztik]

GFS has developed one of its FI deep lows this afternoon

960mb I make it

..and the 18z keeps it

Edited September 10, 2013 by draztik

[William of Walworth]

For 26th or 27th September!

 

Anything can happen ahead of that, and probably will. Not excluding some very autumnal looking lows I accept, many current signals do support this, but its all about tracking, intensity, timing, etc.

 

As ANYWEATHER said, confidence on any detail, track of systems, etc much beyond this coming weekend even!, has got to be quite low.

Edited September 11, 2013 by William of Walworth

[Paul_1978]

We've all seen GFS show deep lows on consecutive runs, only for them to disappear he nearer we get.

[Summer Sun]

..and the 18z keeps it

 

 

00z has lost it

 

 

Any way back in the semi reliable this low is not affecting us as much now according to GFS. The northern isles would get battered but most mainland England and Wales would get away with a breezy spell

 

 

 

 

UKMO and ECM have the low further south

 

[Summer Sun]

Latest from Gibby

 

Good morning. Here is this morning's offerings from the midnight outputs of GFS, UKMO, GEM, NAVGEM and ECM for today Tuesday September 11th 2013.

 

All models show an occlusion close to the SE moving away East. A new set of fronts over the NW are shown to move South and SE through the day bringing outbreaks of rain and drizzle, heaviest in the West through the latter half of today. The cold front then gets hung up over the South as it loops back and returns East over the North tomorrow as a warm front with rain and drizzle for the North and cloudy but less damp weather in the South. As the cold front slips South on Friday and Saturday it develops waves which enhance rainfall over Southern Britain for Friday and Saturday clearing late in the day. The North will be brighter and fresher on Friday and Saturday. By Sunday all models show freshening Westerly winds and fronts approaching from the West with rain following later in the day moving East.

 

GFS then shows the deep Low bringing Sundays rain further North than last evening's midday run and consequently brings less dramatic changes to the South at least. Nevertheless, all areas will see a spell of rain and fresh to strong winds with gales in the North and NE followed by brighter and cooler weather with NW winds, the showers most prolific in the North. Later in the run the weather warms up somewhat for a time, especially across the South as High pressure ridge up into Southern England. This is then pulled east in response to the remains of an ex-tropical storm heading NE towards Iceland and giving the UK a spell of rain as it's cold front clears through and followed by Low pressure to the North delivering further showers or outbreaks of rain in temperatures close to average to end the run.

 

The Fax Charts show a complex array of fronts mostly affecting the South and West with rain and drizzle over the coming days before the large depression forming on Sunday brings a warm and cold front East across the UK at the end of the weekend with wind and rain for all.

 

The GFS Ensembles show very little cohesion following the weekend Low pressure with a wide spread between members showing many different options again this morning. The only general theme I can pick up is that following the weekend rainfall the trend shows rather less rainfall for the South the deeper we move into the run. The temperature profile is hard to quantify today as the average shown by the mean line for the run is skewed by equal warm or chilly options with the operational a warmer outlier in it's latter stages.

 

The Jet Stream shows the off shoot from the flow moving South or SW today in association with today's complex front structure dissolving away later tonight as the main arm rides NE to the North of the UK for tomorrow until the weekend. The flow strengthens early next week innitially across the UK from the NW before lifting slowly North towards Northern Scotland or even further North deeper into next week.

 

UKMO today holds the deep Low to the North of the UK early next week with the brunt of the cold and showery weather held to these areas while Southern areas become at risk of further Atlantic disturbances running East in the flow with spells of rain but less cool conditions than in the North.

 

GEM develops the Low as the other models and maintains Low pressure close to the North and NE of Britain well into next week with unstable, cool and showery conditions for all with the added ingredient of rather more prolonged rainfall at times as troughs running East in the West or NW winds continues until later in the week. Then High pressure builds from the South with a quieter Autumnal spell of dry anticyclonic weather likely for a time towards next weekend.

 

NAVGEM brings the Low pressure towards Northern Scotland at the beginning of next week and holds it there while filling slowly for several days, all the while continuing to spiral areas of cloud, rain and showers East across Britain in a cool West to NW flow.

 

ECM today shows the deep Low to the North and NE of britain at the start of next week with a band of rain followed by showers for all. It then draws a secondary depression into it's flow towards midweek which would bring heavy rain across england and wales followed by very cool Northerly winds and showers to all for a while later in the week before a ridge of High pressure in the wake of the Low topples East over the UK with further low pressure, this time well to the NW delivers cloud and rain on milder SW winds towards the end of the run.

 

In Summary today it's a very mish mash selection of charts which while showing some interesting synoptics offer no cohesion in patterns making next weeks weather extremely difficult to decipher today. It looks odds on that some sort of wet and windy spell early next week is likely, most effective in the North while the South may see no more than a strong breeze and a band of rain. Where that depression goes in the longer term is open for debate this morning as options of High pressure rebuilding or continuing unsettled weather with Low pressure to the North are all shown to some degree or another with anything possible. To use the much used phrase on this forum it's a case of many more runs needed before things become any clearer and commonplace between the models.

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

[johnholmes]

The guidance from the anomaly charts is still not absolutely consistent which may explain why the synoptic models are changing emphasis at times. The fine detail, such as the actual track and depth of the low are for the synoptic models not the anomaly charts. What they do continue to suggest is that there will be some degree of +ve anomaly in heights to the west of the UK. There are signs on all 3 of the +ve heights occurring also north of Greenland. Just what effect this may have is unclear. As to the trough they continue to have it close by the east of the UK at times and at others not. This is the element which is making the models vary in output. For whatever reason the anomaly charts seem unable to be consistent as to where it will be and how marked. Until this is resolved then how settled the weather may become 6 days or so down the line, how much sun and how warm are factors yet to be decided. What they seem consistent with is that the 500mb flow will be from a point west of north not south of west.

Edited September 11, 2013 by johnholmes

[Richie V]

A tad off topic but, what happened to Gibby? Why dose'nt he post in here now?

Ric

[Summer Sun]

A tad off topic but, what happened to Gibby? Why dose'nt he post in here now?

Ric

 

http://forum.netweather.tv/topic/77405-model-output-discussion-18z-280713/?p=2782426

[Summer Sun]

06z GFS builds pressure in fairly quickly once the low has moved away

 

[Yarmy]

Just to reiterate yesterday's point, these are the sort of the charts I'm looking for at this stage of the year.

 

 

Pleasantly warm and settled for us, but Siberia going into the freezer and Scandinavia/Russia getting a taste of it to set the building blocks for Winter.

 

Of course, it won't happen because it's T324, but it would be a useful pattern to get into. Then come late November the AZH can do one and head to Greenland.