Model Output Discussion 12z 18/10/2012

[andymusic]

Wales could well have some serious amounts of rain and wind next week leading to some further flooding problems!

[camiscool]

gfs downgrades cold again just a little cold now with rain. GREAT.

[Frosty.]

gfs downgrades cold again just a little cold now with rain. GREAT.

gfs downgrades cold again just a little cold now with rain. GREAT.

It's only an op run, taking all the models as a whole, next week is still looking rather cold and unsettled with rain and showers and snow at times on hills and perhaps down to modest levels in the colder shots, there is still a lot of fine tuning to come, fri/sat will be relatively cold with widespread frosts and a risk of wintry showers but most of the showers in the far north and east, then less cold and wet on sunday before it turns colder again, also some frosts next week where skies clear overnight and winds drop although for most of the time it does look breezy or windy at times.

[Gowon]

Evening guys-

Just a quick one from me-

Keep an eye on the UKMO trough at 48 through 60 on the 12z

A band of rain sleet & snow down through the UK sat eve..

Can someone link the europe 48 & 60 chart for clarity

S

Yep, along with GEM they're the only models so far to bring that SW further West at 48 to 60. The UKMO also brings colder air further South at 60h, so maybe a chance of wintry ppn further South.

Edited October 24, 2012 by Seselwa

[Chess01]

How are things looking for the future

[legritter]

I still see a good interesting run from the GFS .plenty of interesting synoptics on offer .it will be interesting to see how the ECM puts the low pressure next week over the next couple of runs . but interesting highs over the higher latitudes giving us a shot later out perhaps .and certainly going by all modells the flood situation could be back .with favoured locations having a wintry mix chucked in for good measure .well roll out the ECM ,

[MR EXTREMES]

Spot the UK!

http://www.meteociel...npara=0&carte=1

A rather unsettled run after the cold snap this weekend. Plenty of rain around for all, along with some windy days. Temps often on the cool side of average.

http://www.meteociel...&mode=0&carte=1

how impressive is the greenland high pressure in the unrealiable timeframe thats a mighty block setup there,

little far west but below average in temps and above in rainfall/snowfall could be setting up nicely for november if the block shifts east.

very stormy and pressure heights showing similar values to 09/10 winter something to keep an eye on.

but could change due to active hurricaine and tropical storm growth.

could this be el nino strengthening always a good sign for cold weather fans.

[Frosty.]

How are things looking for the future

Mostly unsettled and rather cold but windy, becoming drier and brighter in western and central areas for a time but cold showers further north/east (mainly coastal), then wet and less cold on sunday as a small low slips southeast and mixes out the arctic air but then a return of polar maritime/arctic type airmass next week as the scandi trough possibly moves west towards the uk and pressure remains generally higher to the west and nw towards greenland but migrating more towards canada in the longer run.

[Chess01]

Mostly unsettled and rather cold but windy, becoming drier and brighter in western and central areas for a time but cold showers further north/east (mainly coastal), then wet and less cold on sunday as a small low slips southeast and mixes out the arctic air but then a return of polar maritime/arctic type airmass next week as the scandi trough possibly moves west towards the uk and pressure remains generally higher to the west and nw towards greenland but migrating more towards canada in the longer run.

Is that good signs for things in the longer run

[summer blizzard]

how impressive is the greenland high pressure in the unrealiable timeframe thats a mighty block setup there,

little far west but below average in temps and above in rainfall/snowfall could be setting up nicely for november if the block shifts east.

very stormy and pressure heights showing similar values to 09/10 winter something to keep an eye on.

but could change due to active hurricaine and tropical storm growth.

could this be el nino strengthening always a good sign for cold weather fans.

El Nino is dead, GLAMM is very low and there is every prospect that La Nina could develop next Spring.

[phil nw.]

Can we keep to the model outputs please.Some posts are better in other threads and have been deleted.

[Isolated Frost]

Today's ECM on the right, Friday 12pm. Yesterday's ECM on the left, same time. Interesting to note the westward shift in HP already, and that trough that was noted on the UKMO has also been factored in. That trough o/ Shetland could very well deliver some precipitation to inland NE Scotland and NE England/N Yorkshire on Friday evening.

[BLAST FROM THE PAST]

Spot the UK!

http://www.meteociel...npara=0&carte=1

A rather unsettled run after the cold snap this weekend. Plenty of rain around for all, along with some windy days. Temps often on the cool side of average.

http://www.meteociel...&mode=0&carte=1

Considering that we are in October and the outlook is for continued surpessed temps with a potential humdinger storm I'd say its a cold spell as there is no mild in sight?

I've got to say I've been watching this potential 'bomb'....looking at the UKMO it looks a complicated set up come t144 and that IMO could manifest itself into a period of prolonged and heavy precipitation in fairly stormy conditions. And it will feel decidedly chilly. Ground is 'hreavy' in many places so a period of concern could be ahead.

UKMO at t144.

Below GFS t138

Less than 2 days later at t180, GFS comes up with this

With pressure low south of UK at t138/144 range and trough sinking north of us I think this is a plausible development. Whether as deep is not an issue IMO as its slow moving, lots of wet.....wet we don't actually need.

Edit....ECM heading same way......

BFTP

Edited October 24, 2012 by BLAST FROM THE PAST

[snowmadchrisuk]

Today's ECM on the right, Friday 12pm. Yesterday's ECM on the left, same time. Interesting to note the westward shift in HP already, and that trough that was noted on the UKMO has also been factored in. That trough o/ Shetland could very well deliver some precipitation to inland NE Scotland and NE England/N Yorkshire on Friday evening.

Based purely on the GFS , I would say Skegness , Boston and maybe even as far West as Peterborough stand a chance on Friday afternoon. It looks like the flow will be strong enough to push Snow showers a fair way inland from the wash area as it is positioned just right . Doubt it they would get as far as Notts/Leic but I have seen surprises in these sort of setups. Further down the line , it looks like were going into a setup very much like when the DEC 2010 episode broke down. In that setup it remained as Snow for a week due to the stuben surface Cold. I would like to see the Blocking move further Eastwards as we head towards December, as nothing can really get sustained when the HP is ridging as far West as Canada.

Edited October 24, 2012 by snowmadchrisuk

[andymusic]

Spot the mistake???????????????????????????????

(Greenie high has turned into a greenie low on this map!!!!!!!!!!!!!)

Edited October 24, 2012 by andymusic

[BLAST FROM THE PAST]

Spot the mistake???????????????????????????????

(Greenie high has turned into a greenie low on this map!!!!!!!!!!!!!)

Its no mistake....its correct at that timescale....move it forward and pressure rebuilds

BFTP

[Chris D]

Its no mistake....its correct at that timescale....move it forward and pressure rebuilds

BFTP

It is weird however that the centre of the HP is labelled as LP. Unless I am missing something?

Edited October 24, 2012 by Chris D

[johnholmes]

Based purely on the GFS , I would say Skegness , Boston and maybe even as far West as Peterborough stand a chance on Friday afternoon. It looks like the flow will be strong enough to push Snow showers a fair way inland from the wash area as it is positioned just right . Doubt it they would get as far as Notts/Leic but I have seen surprises in these sort of setups. Further down the line , it looks like were going into a setup very much like when the DEC 2010 episode broke down. In that setup it remained as Snow for a week due to the stuben surface Cold. I would like to see the Blocking move further Eastwards as we head towards December, as nothing can really get sustained when the HP is ridging as far West as Canada.

Sorry to pour cold water on the idea of snow in the areas you suggest, at least not if the 12z GFS version in Extra is to be believed?

Dropping the variables for will it won't it snow apart from the precipitation showing up, 3-4mm over about 6 hours none of the other parameters, T, Td, wet bulb T, 0 C isotherm, 850mb temperature or 1000-850mb thickness give a yes?

Edited October 24, 2012 by johnholmes

[Cloud 10]

LOL,polar vortex to set up shop just west of Scotland!

[BLAST FROM THE PAST]

It is weird however that the centre of the HP is labelled as LP. Unless I am missing something?

Ahh Chris, the HP south of Greenland is the mistake....yes good spot

BFTP

[Gibby]

Good evening folks. Here's my take on the 12zs of GFS, UKMO and ECM tonight.

All models show the recent slack East or north-East flow over the British Isles strengthening slowly over the next 24 hours as the pressure gradient steepens over the UK. The current cloudy and drizzly weather will begin to be eroded from the North by clearer and colder conditions, reaching the far North tomorrow morning and the far South during Friday. Winds will back Northerly and become fresh and very cold with temperatures falling markedly everywhere within the next 48 hours. Once arrived the weather will be typified by bright and crisp conditions with sunny spells by day and frosty nights. In addition there could be a few wintry showers in northern and Eastern coastal areas of Scotland for a time. By Sunday winds will back West or NW as Low pressure to the North deepens and move SE swinging a trough SE with it carrying a band of rain and fresh winds but slightly higher temperatures, By Monday the trough will of passed and the weather will revert to cold conditions again with the likelihood of showers, wintry on hills in the North.

GFS then shows low pressure sitting close to the SW on Monday and as it moves away reinforcements are introduced from the NW by midweek, making for a cold and unsettled spell with rain and showers plus snow on Northern hills everywhere for the remainder of the working week. By Thursday a very deep Low sits over Southern Britain and is slow to fill and move away maintaining the same conditions through the weekend as it only slowly drifts away East early in FI with a cold and showery North or North-West flow in it's wake. As FI moves on things dry up and become less cold for a while before things return wet and windy once more by the end of the run.

The GFS Ensembles place the operational as a chilly option, then a briefly warmer one towards the end of FI with the period up to that point being fairly representational of the pack. The majority of members average out at a level below the seasonal norm with a slowly narrowing differential towards the end. Some large precipitation spikes are shown mostly indicative of cold zonal conditions the most likely outcome.

The Jet Stream shows the Northern arm of the Jet increasingly turning South in direction over the British isles to reach the Southern arm over Southern Europe later in the weekend and next week.

UKMO for midday on Tuesday shows a complex syatem of cold Low pressure stretching from Western France to Scandinavia to Iceland with a cyclonic flow of winds affecting the British isles. There would be areas of rain and showers scattered about over the UK and with temperatures on the cold side of normal some sleet or snow could be expected at times on high ground from Snowdonia North.

ECM shows a slightly different strategy of Low pressure lying to the North of the UK with a chilly if reasonably slack and showery Westerly flow over the UK. Showers would occur mostly near windward coasts in the West where they could be heavy and wintry in the North while some places could stay dry and bright It then evolves forward by deep Low pressure near western Scotland with much stronger SW winds and heavy showers for all areas in still (despite SW Winds) somewhat chilly conditions. The end of the run is dominated by an intense depression close to Western Britain with a deep cold pool aloft delivering a lot of convective showers and thunderstorms especially near Southern and western coasts and further snowfall over the higher Northern hills.

In Summary the weather looks like becoming distinctly unsettled and potentially stormy as the Arctic winds moving South as a result of High pressure over Greenland mixing with warmer air of more Southern latitude origin promoting deep depression growth somewhere close to the UK through the week. There could well be some large rainfall totals locally with hail and thunder likely at times under the convective spells. Temperatures will be somewhat below normal, sufficiently so at times for snow on Northern hills but this looks unlikely to be a widespread problem.

[BLAST FROM THE PAST]

LOL,polar vortex to set up shop just west of Scotland!

And th GP N Pacific LP is there

BFTP

[Snowy Easterlies]

just looks like normal atlantic conditions to me, plus don't these lows always end up further north when the time gets closer and the south ends up with boring high pressure which just brings in mild air and cloud, whilst its wet in the north and west

Edited October 24, 2012 by Snowy Easterlies

[bluearmy]

just looks like normal atlantic conditions to me, plus don't these lows always end up further north when the time gets closer and the south ends up with boring high pressure which just brings in mild air and cloud, whilst its wet in the north and west

But the NH chart doesn't look like a normal Atlantic

Excellent to see ECM day 10 still blocked over the NH and high anomolys out to the end of week 2 on naefs.

[Snowy Easterlies]

i know the NH doesn't look normal but there is far to much emphasis on northern blocking on here im afraid, the fact is this island just looks to have normal autumn weather next week, this weekend looks quite chilly though

yes ECM FI looks blocked but its FI so until this northern blocking has a real impact on this island, i don;t care how much blocking there is over greenland or the NH, as we all know northern blocking doesn't always mean cold for us, i know it dosen't look milder in the near future but as i said these lows that are shown for next week could end up further north, meaning the south becomes milder, i remember nick sussex saying this often happens and he was right as it happened last autumn and winter

Edited October 24, 2012 by Snowy Easterlies