Model Output Discussion - Late October Onwards

[Liam J]

You'll never be able to prevent anyone from posting charts if they show the prefered weather type of that individual even if they are charts picked from deep FI with no support and with little or no chance of varifying. I'm sure the members posting such charts are well aware of this, well I hope so as I do wonder sometimes!!

Edited October 24, 2011 by Liam J

[Radiating Dendrite]

The interesting thing about the last two runs is the southerly tracking Jet.

Both show a channel low set up (despite differing synoptics after this).

This for me is significant as it is at +288 and deep in FI. To get agreement on something like this across two runs at that sort timeframe is unusual and certainly something to watch out for in later runs.

I think that colder weather could be around the corner, possibly after the 10th of next month. We will have to go through some zonal stuff before we get there, but the GFS is now starting to show some increasingly interesting charts in FI.

[Frosty.]

The latest models show most of this week being unsettled although the worst of the rain is for today and tonight and then it looks more showery in nature with the persistent rain clearing the east coast tomorrow and moving slowly north across scotland as a weakening feature. Friday looks a fine day in most areas but then into the weekend we have a nw / se split with the european high pressure extending across southeast britain but northern and western areas becoming windier and more unsettled. The Ecm 00z looks more settled than the Gfs 06z beyond this week with some fairly benign conditions but the Gfs 06z turns into a much more unsettled run with the atlantic powering up and a constant stream of depressions crossing the uk, at least the temps look reasonable for most of the time but with a few colder days in the polar maritime flow.

[Liam J]

The interesting thing about the last two runs is the southerly tracking Jet.

Both show a channel low set up (despite differing synoptics after this).

This for me is significant as it is at +288 and deep in FI. To get agreement on something like this across two runs at that sort timeframe is unusual and certainly something to watch out for in later runs.

I think that colder weather could be around the corner, possibly after the 10th of next month. We will have to go through some zonal stuff before we get there, but the GFS is now starting to show some increasingly interesting charts in FI.

These synoptics will then need to make it closer to the reliable timeframe with following runs and not be held out to +288 hours or later, then also gain support from the others before we can start making assumptions on the outcome. Lot's of swings and roundabouts and weather to come before we get to November.

But as you say interesting to see two runs back to back from the GFS showning very similar synoptic charts in FI, it could be onto something here or it could be just a coinsidence. We shall find out soon enough on future runs.

[Radiating Dendrite]

These synoptics will then need to make it closer to the reliable timeframe with following runs and not be held out to +288 hours or later, then also gain support from the others before we can start making assumptions on the outcome. Lot's of swings and roundabouts and weather to come before we get to November.

But as you say interesting to see two runs back to back from the GFS showning very similar synoptic charts in FI, it could be onto something here or it could be just a coinsidence. We shall find out soon enough on future runs.

Yes, as we know anything in FI is subject to change, but it is interesting to note that the Jet is keen to head south.

In FI you can only look for trends and this could be the start of one.

People say FI is useless, but if it is so useless then why do they have it available? Trends in FI are important and can often suddenly appear in the reliable as we saw a number of times last year.

[trisnow]

Sorry as this is sort of off-topic but - are there threads from around this time last year discussing the model output?

It appears there aren't any in this "Forecasting Model Discussion" forum looking further down so is there an archive somewhere?

Interested as to read all your guys comments as it all began to pan out last year.

Thanks in advance.

[Radiating Dendrite]

This is the archive section:

http://forum.netweather.tv/forum/72-forum-archive/

Does not seem to be a MOD section in there though.

[trisnow]

Thanks RD, yup had a look and couldn't see a Model Discussion archive.

Maybe this is a new sub-forum this yar then?

[Radiating Dendrite]

Thanks RD, yup had a look and couldn't see a Model Discussion archive.

Maybe this is a new sub-forum this yar then?

It is possible that it was previously part of the Seasonal Discussion Thread, I cannot remember.

Best PM Paul

[bobbydog]

Yes, as we know anything in FI is subject to change, but it is interesting to note that the Jet is keen to head south.

In FI you can only look for trends and this could be the start of one.

People say FI is useless, but if it is so useless then why do they have it available? Trends in FI are important and can often suddenly appear in the reliable as we saw a number of times last year.

talking of FI, the jet does seem to be trying to take a more southerly track, but in order for us to get any significant cold, after reading Chio's excellent post abut stratospheric warming, we need disruption to the polar vortex, or the cold just stays locked at the pole.

could this be what we are seeing here?

edit: this is a question to other members, anyone care to answer it?

Edited October 24, 2011 by bobbydog

[kold weather]

Pattern looks condusive for a very mild pattern to continue in some form, you've got the upper trough to the west and a stubborn ridge being pumped up to the east and that means its next to impossible to shift away from a SW-S wind pattern with rainbands coming in but mainly the ehavy stuff for the west.

Classic mild pattern, borderline warm at times...

[Gibby]

Good evening. Here is my take on the 12zs from GFS, UKMO and ECM.

GFS tonight shows a cold front crossing England and Wales as I type with a band of weakening rainfall moving NE with strong southerly winds ahead of it. Drier weather follows and the mopping up process for the extreme SW and Northern Ireland can begin. Tomorrow a showery SW flow covers the UK with the cold front by then over the NE giving heavy rain there through the day. More rain then is shown to spread up temporarily from the South into southern Britain on Thursday. This weakens as pressure rises quickly over the South to give a day or two of dry, bright and mild weather. Low pressure then moves towards the NW with strengthening SW winds and rain on Saturday and then extending to other areas through Sunday and beyond. Through FI tonight a typical Autumn pattern is shown with spells of rain and showers in rather windy conditions and some cooler weather at times too.

The GFS Ensembles show a normal Atlantic pattern for Autumn with wind and rain aplenty in a mobile Atlantic pattern. Consequently the majority of members stay close to the long term average when taken as a package.

UKMO tonight also takes the GFS route through its 144hr period with Low pressure closing in on the UK over the weekend with further wind and rain as we move into next week.

ECM completes the trio in the weather patterns for this week and then goes on to show a repeat of the synoptics of the last few days early next week, with a band of heavy rain moving slowly East into Western Britain while very mild SSW winds affect the UK between deep Atlantic Low pressure to the West and continuing High pressure over Europe. Eastern areas would probably once more stay dry and bright if breezy.

In Summary tonight a typical Autumn period of weather is shown. With Low pressure to the North, northwest or West mild South or Southwest winds prevail with rain or showers at times for all, as usual heaviest in the West and North. There looks little possibility of widespread frosts or cold weather on any of the output tonight.

[bobbydog]

Pattern looks condusive for a very mild pattern to continue in some form, you've got the upper trough to the west and a stubborn ridge being pumped up to the east and that means its next to impossible to shift away from a SW-S wind pattern with rainbands coming in but mainly the ehavy stuff for the west.

Classic mild pattern, borderline warm at times...

thanks for the answer KW, though i wasn't particularly asking about our weather as regards this particular chart, more about the fact that the PV is (i think) showing progressively more disruption throughout the run, which would be one of the key ingredients for colder weather for us, at some point.

Edited October 24, 2011 by bobbydog

[phil nw.]

Thanks for your usual clear summary Gibby.

Not quite the typical Autumn Atlantic West to East pattern imo though.

That Euro block is never far away right out to the end of the week.

In spite of the deluge further West over here and further East we still need the rain and tonights rainband looks like fragmenting as it comes through.

In the medium term it still a NW/SE divide it seems with high pressure never far away from the South and East.

[Strider]

Funny there's no posts about FI tonight... hopefully a lesson learned for some. If you base your predications on T300+ you'll have a heart attack before December!!

Looks like the usual autumn fare to me, wet and windy for most with Atlantic dominated weather.

[kold weather]

I suspect the reason why there is no FI posts is because there is NO cold weather in sight on the models, its pretty much constant variation of the mild pattern we are in right now. Early days but with the PV already showing hints of setting up, could be very frustrating model watching this winter...

[Snowstorm1]

I suspect the reason why there is no FI posts is because there is NO cold weather in sight on the models, its pretty much constant variation of the mild pattern we are in right now. Early days but with the PV already showing hints of setting up, could be very frustrating model watching this winter...

Come on Kold weather with your very experienced knowledge you know this pattern could easily change within a few weeks (No dig intended at all just commenting as don't want all the negativity again! ) Back to the models and yes it pretty much a mild dominated pattern currently shown with bands of rain interspersed with spells of sunshine; which personally I think is good and soon enough it will run out of steam then lets see where we go....

Edited October 24, 2011 by Snowstorm1

[Frosty.]

High Pressure has never been far away from SE Britain for the last 6 months which is why the southeast had a fairly good summer but nobody else did apart from the freak early october heatwave but again scotland & n.ireland missed out. The latest models show the euro high being a thorn in the side to any colder incursions, no chance of anything wintry until the euro high buggers off with the winds mostly from south of west with the most unsettled weather in the north & west.

[kold weather]

Come on Kold weather with your very experienced knowledge you know this pattern could easily change within a few weeks (No dig intended at all just commenting as don't want all the negativity again! ) Back to the models and yes it pretty much a mild dominated pattern currently shown with bands of rain interspersed with spells of sunshine; which personally I think is good and soon enough it will run out of steam then lets see where we go....

Very true it is early days I admit!

Still i never do like to see too much ofn a PV set-up this early, however November-December 2009 shows how a pattern can shift really quite rapidly so I'm not too concerned just yet, even if the stratospheric set-up leaves me more concerned.

[Thundery wintry showers]

Looks like the returning polar maritime airmass will make it to our shores tomorrow, but with generally southerly winds showers will tend to be restricted to western and southern areas. A slow moving frontal system is projected to give some rain on Thursday, followed by high pressure and southerly winds on Friday and into the weekend. The current GFS outputs suggest relatively cloud free skies across England and Wales, resulting in dry, sunny and fairly warm weather by day (13-16C max) and chilly nights, while most of Scotland and Ireland and Wales will be cloudier, with some rain in the north-west.

All three of the major models suggest that the Atlantic will try to push in afterwards but that high pressure will remain stubborn to the east, resulting in frequent southerly winds, and thus generally warm, changeable weather.

[Liam J]

It seems to have gone awfully quiet on here?!

The 12z models show a very mobile and relatively mild period right out to FI with cross model agreement for an Atlantic dominated period. No cold weather showing in the long term, for the time being anyway.

[Backtrack]

Sorry as this is sort of off-topic but - are there threads from around this time last year discussing the model output?

It appears there aren't any in this "Forecasting Model Discussion" forum looking further down so is there an archive somewhere?

Interested as to read all your guys comments as it all began to pan out last year.

Thanks in advance.

Unfortunately they don't archive the Model Output I don't think.

[damianslaw]

High Pressure has never been far away from SE Britain for the last 6 months which is why the southeast had a fairly good summer but nobody else did apart from the freak early october heatwave but again scotland & n.ireland missed out. The latest models show the euro high being a thorn in the side to any colder incursions, no chance of anything wintry until the euro high buggers off with the winds mostly from south of west with the most unsettled weather in the north & west.

Yes the stubborn strong heights out to our east are preventing any colder set up developing, until they shift out of the way (the sooner the better I say!) we will remain locked in a mild southwesterly flow with the heaviest rain reserved yet again for the NW of the country - just where it isn't needed. The jet is desperately trying to move southwards at the moment but coming up against a brick wall due to those heights to our east. However, I do believe as we move into early November we will see some stronger pressure gradients develop in the mid atlantic thanks to those increasingly colder uppers to our north causing marked temperature gradients - thus expect some deep low formation - strong enough to blast into those heights to our east thus sinking them away and finally allowing some proper polar maritime air to move into the country. We saw signs of a southerly jet early last week with an injection of polar maritime air and believe me when it arrived in the Highlands it was jolly cold with some preety low level snowfalls and low daytime maxima for a short time.

Whilst the reliable timeframe is very poor this evening for any cold weather - longer term the prospects are shaping up well provided those heights to our east clear away... GFS is showing a colder theme in the long term and ECM did yesterday... whilst we shouldn't hang off fantsy island charts we do need to look longer term at the overall trends and I believe the southerly tracking jet will deliver goods in time just give it some time - patience is needed.

[johnholmes]

I think anyone hopecasting for cold weather, other than the occaional overnight frost, into mid November at least, is likely to be disappointed. I can see nothing to suggest anything other than normal autumnal weather, windy in places at times, rain at times, heavy on any waving and slow moving fronts (cold fronts especially), a temporary ridge now and then, less unsettled in the far south/southeast, but no sign of any cold spell or snow-sorry cold lovers.

What do I base this on-sorry not got time to do a pdf with charts but look at the AO/NAO, 500mb anomaly charts, MJO, 30mb temps etc-nothing solid enough amongst any of those to suggest any cold spell?

Oh I also see GP is suggesting much the same idea on the technical thread.

[wimblettben]

Looks to me that we could well be about to see a repeat of 2009 in terms of when the cold arrives. So a wet and windy November but then overall a cold December and January.