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Model Output Discussion 06Z, 13 Sep. 2013 ---->


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Today's Gfs 12z operational run follows the pattern of the previous runs so far today in that it shows an increasingly unsettled pattern with strong winds at times but those winds are generally from either south of east, due south or south of west for at least the next 10 days with temperatures on the warm side of average and in the drier and sunnier spells between the heavy thundery showers and more persistent rain it will be feeling very warm for the time of year with temperatures well into the 70's F but generally in the high teens to low 20's c. During next week the 12z shows a tightening up of the isobars as the controlling atlantic depression edges closer and high pressure to the east does likewise, it creates a spell of strong to gale force SE'ly winds for the north & east of the uk along with heavy rain as fronts try to push further east but stall, that could be a big problem next week if fronts do stall coming up against the block to the east. Later in the run there is a brief amplification of the upstream pattern bringing the first polar maritime blast of the season as low pressure to the north finally pushes further east and there would be wintry showers across the hills and mountains in scotland and overnight slight frosts but guess what happens next..a reboot with almost a carbon copy of the current weather and the south never really feels the pinch of that very cool snap which mainly affects the north of the uk, at least the met office hint of a colder shot for the northwest is again showing on the gfs 12z, as it did on the 6z.Posted Image

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Edited by Frosty.
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This weather is just awful, sweaty and humid, can't wait for some proper cold weather.

I think we still need to wait about a month until we can get some proper cold to be honest. September isn't exactly renowned for being cold and neither is early October to be honest.

I do wish the showers for the weekend could get an extra northerly push so they affect more than the south coast. Otherwise the weekend looks pretty dry and I'm sure there would be some sunshine for many. Temperatures for the next week look mild to warm away from windward coasts where it will be a little cooler.

Kind of sitting around twiddling our thumbs waiting for something to happen, warm, cold, wet, sunny, thunder, snow. When this finally snaps we will definitely notice it.

Good work by the ECM by the way, spotted next weeks pattern out at 9/10 days away, recovering from some woeful performances over the summer along with the other models.

Edited by Captain shortwave
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It's almost an extended Summer, it's like revenge for the extended Winter we endured! Hopefully the very mild weather will last. Looking quite dry here too Posted Image

 

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Edited by Gaz1985
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ECM pretty much as you were the low can't get in and dies away out in the Atlantic with the high to our east warm uppers continue to flood in

 

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t216 sees the high moving eastwards

 

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Edited by Summer Sun
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The GEFS 12z mean is indicating an october chill with the PFJ finally deciding enough is enough and plunging south, maybe the seeds of the first rather cold incursion are being sown.Posted Image

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still need lots more time to nail the October settled spell although warmth showing on the models tonight what a difference a day make watch the slow climb down slowly but sure them low pressure systems are sliding more and more se.

and the azores heights are slowly each day getting pushed futher and futher south intresting for those looking for a cool down and something a little different.

say good by to summer temps are likely to be above average for a lil while yet but bets are on the weather will become more and more unsettled with the north dryer than the south and sw its intresting watching the models throw up the heat but then slowly backing of.

autumn is now approaching.

I expect to see futher back tracking and I will say well done the met office for calling the unsettled pattern.

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I expect to see futher back tracking and I will say well done the met office for calling the unsettled pattern.

The met office have been hinting at a rather cold incursion both yesterday and today for towards the end of the 6-15 day outlook, I think there is growing support for it too with the gfs 6z and 12z showing it and the gefs 12z mean, it will be a little while yet before it comes into the ecm range but there is a chance it will, the ecm 12z op run tonight shows the atlantic eventually waking up and sending lows our way on more of a nw/se track, we have to start somewhere.

Edited by Frosty.
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Latest from Gibby

 

Good evening. Here is the report on the 12 midday outputs from GFS, UKMO, GEM, NAVGEM and ECM for tonight Wednesday September 25th 2013.All models continue to show warm air across Southern Britain but there is a colder feed of air making some progress South across Northern and Eastern areas currently. There is a lot of dry weather about but some bursts of showery rain too in places at times especially in the South and West over the next 24 hours and much more so over the weekend as some heavy and thundery rain is shown to affect the South at times while the North stays rather direr and brighter in somewhat cooler temperatures away from the far North.

 

GFS then shows a West/East split next week with warm Southerly winds pushing back up across Northern areas too early next week. Troughs will be ganging up to the West of Britain and are likely to make inroads East across Britain, to what extent though is very uncertain. As it stands spells of quite weather would be likely in the West while Eastern areas would more likely see drier and brighter spells between the rain. The latter end of the run indicates changeable conditions with rather cooler air in place too. There would be some dry and brighter spells almost everywhere at times when quiet and settled days could lead to overnight fog before the next band of rain moves in.

 

UKMO tonight shows Low pressure to the SW towards the middle of next week with further troughs carrying bands of showery rain North across Britain with temperatures probably a little lower than recently in SE winds.

 

GEM tonight shows quite a windy period next week as deep Low pressure lies close to the West. The winds will be from the South and it would still feel reasonably warm for many outside of the rain, which would come in bands East and North across principally Western locations with the driest conditions to the East, though even here some heavy rain could be possible at times.

 

NAVGEM too shows a feed of South or SE winds lasting well into next week with some rain at times in the South and West. The far East though may not see too much rain for a time before all areas become more at risk at the end of the run as pressure falls.

 

ECM tonight shows broadly similar trends to this morning with unsettled conditions for much of the period as Low pressure remains to the West and SW before showing signs of moving away NE late in the run. There would be rain at times throughout, potentially heavy in places, especially in the South and West for much of the run before the north and West become more at risk later. All areas could see some drier spells too with the East likely to see the best of these. It will stay on the warm side of average throughout as winds are maintained mostly between SE and SW. The GFS Ensembles show a slow decline in uppers towards average by the end of the run. The weather turns changeable for most areas with occasional rain at times throughout.

 

The Jet Stream shows the flow to the North virtually dead in the water now as the circulation to the SW takes control as it links with a new arm exiting the Atlantic to form a Southern arm crossing East towards France. The indications for the period beyond the middle of next week are very sketchy and not worthy if comment at this range. 

 

In summary the weather looks like staying fairly static in it's pattern with Low pressure looking odds on to remain close to the SW and West through the period with outbreaks of rain and heavy showers pushing North on occasion while High pressure to the NE and East holds enough influence to ward off the worst of the rain from more Eastern locations where longer dry spells rather than wet look likely. Temperatures although slipping back will never fall that much and even at the end of the run in average uppers any sunnier moments between the rain bands will feel pleasant enough.

 

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

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It's nice to see that growing mass of very cold air further north with 510 and 522 dam...hopefully we will see plenty of that through late autumn and during winter,Posted Image Posted Image

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It's nice to see that growing mass of very cold air further north with 510 and 522 dam...hopefully we will see plenty of that through late autumn and during winter,Posted Image Posted Image

I hope that that stays where it is; we've got to keep the SSTs up, at least until mid-November...Posted Image 

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I hope that that stays where it is; we've got to keep the SSTs up, at least until mid-November...Posted Image 

I hope we will have had at least a few cold incursions before then pete :-)
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I think we still need to wait about a month until we can get some proper cold to be honest. September isn't exactly renowned for being cold and neither is early October to be honest.

I do wish the showers for the weekend could get an extra northerly push so they affect more than the south coast. Otherwise the weekend looks pretty dry and I'm sure there would be some sunshine for many. Temperatures for the next week look mild to warm away from windward coasts where it will be a little cooler.

Kind of sitting around twiddling our thumbs waiting for something to happen, warm, cold, wet, sunny, thunder, snow. When this finally snaps we will definitely notice it.

Good work by the ECM by the way, spotted next weeks pattern out at 9/10 days away, recovering from some woeful performances over the summer along with the other models.

 

We should remember late September/early October is on average warmer than late May.. but also tends to be much more unsettled than late Spring..

 

It is a case of waiting for the inevitable to happen i.e. the atlantic trough crashing through heights to our east - and I suspect thereafter we will see a marked cool down. Until this happens enjoy the very benign spell of current weather - its dull as dishwater for model watching but very pleasant all the same.

 

I'm looking forward to the first frosts..

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I think the models are now seeing what lies beyond the warm unsettled outlook and it involves the first proper frosts and an accumulation of snow on northern higher hills and mountains towards mid october, the gefs 12z mean has given me hope tonight.

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looking at the 500mb anomaly charts over the last couple or so of days, this evening my notes show this

Noaa

Both 6-10 and 8-14 are pretty similar to their last issue

Is some semblance of continuity starting to appear? Ec quite like noaa 6-10 over past 2 days, gfs not as much but not totally different

This might imply as noaa 6-10 becoming as noaa 8-14 as a reasonable guide for the upper air pattern in those time scales?

In terms of heights noaa suggests 5700dm (channel area/n france) with air originating from just south of Gt Lakes so neither hot nor cold, average or a bit above and weather a bit unsettled looking at the 500mb flow, speed etc?

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So err.... where's the cold unsettled weather

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Not here, no real signs

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Ens mean from the ECM has the jet tilted the wrong way to support that claim

GEM not going for it either, more mixed but certainly not cold.

I'm rather baffled myself, given the models have called the last week and the coming week unsettled and cool on several occasions before backtracking to an almost bone dry solution. How can we even trust that, given that the only model going for it is the GFS which with blocking to the north east make it seem even more dodgy in my opinion. 

Lets be honest, this pattern isn't really ideal for anyone as it suits neither extreme at this time of year, but lets be realistic, until the models show this scenario with reasonable agreement, surely it's no more than just hopecasting. Whilst the metoffice state otherwise, it's worth bearing that recently the metoffice outlook has flipped from wet to dry and back again within just a few outputs, so again they might be calling a settled outlook on tomorrow or Fridays outlooks.

This is flimsy at best but again, the latest GFS at day 10

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High pressure in charge.

Even I'm bored but we have to be realistic with what we have in front of us, given where the models are at day 7 which has good agreement, you can't get to a cold and wet solution very quickly from there without some kind of assistance.

If I was going to express an opinion to where we go, it will be a slow and painful breakdown which will finally allow low pressure to push east by about day9/10, but I think we will probably end up in a north/south split with the flow between the south west and west.

Edited by Captain shortwave
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All I can say is there has been some evidence of a colder incursion for the first time this autumn on the gefs 12z mean with the jet becoming aligned nw-se with an amplified pattern, also the gfs ops showing an autumn chill beyond t+240 hours and added to that the met office mention of rather colder weather within the next few weeks...things are beginning to change.

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