Model Output Discussion

[Coast]

New thread for discussion of the latest model output.

[johncoolj]

Looks like the AO index is about to go lower then it was back in the big freeze have a look here http://www.cpc.noaa....index_mrf.shtml

at the 14 AO day forcast its going to hit -5 to - 6

this supports the latest model output in regards to a cold spell hitting uk and ireland around the 8th of feb

Edited January 27, 2010 by johncoolj

[kold weather]

The AO is a very good thing to have on your side but it can be over-riden, 97-98 winter had a spell of very -ve AO in one of its months (can't remember which one rignt now though!) and yet that was mild throughout pretty much.

What we see on the 06z is just how tight it is, as I've been saying its a VERY fragile set-up and could easily allow a few days of much milder stuff in IF it goes wrong. However even then there is a very solid trend for the whole lot to get adjusted northwards once we get towards 240hrs...and interestingly there is probably more support from the 06z GFS ensembles for the ECM then on its own model suite!

For now though the most likely evolution once again is for some sort of UK high to build, we could yet get lucky and cash in on an easterly, or of course we could get unlucky and the high justs sits to our SW and stays solid and helps give us a nice mild WSW airflow...

[BLAST FROM THE PAST]

There is so much modelling still to go on folks and so much to get through even by this weekend! The models are increasing the disturbance and LP SWs affecting the UK and Ireland coming down from the north remember peak energy period so disturbed pattern [i thought WNW rather than the north!]. Now I think folk should hold back a little and watch fro developments. The evolution into and through Feb is HP to our W, migrating NW and initially a N to NE'ly flow with a trough in place over Scandi....so always coldest NE and least cold far SW. An easterly IMO is coming as the HP/block eases ESE towards Scandi BUT that isn't by 3/4/5 Feb and may not even get there, that IMO is into second week at the earliest but more likely into second half of Feb.....the trough in Scandi may be there for some time. However, cold to very cold at times....mid to end of second week for coldest period ie 9-14.

KW, just read your post, this is total different kettle of fish and AO and El Nino have behaved differntly more like 40s to 70s because IMO of the one main common ground...the perturbation cycle which lasts [give or take a year ot two] for 36yrs. We entered the Nina phase like the 40s to 70s in Feb 07 and since then we certainly have been experincing an ongoing southerly jet dominance. Sorry OT but just a view of one main reason why IMO this cold pattern IMO is more likely to develop again.

BFTP

Edited January 27, 2010 by BLAST FROM THE PAST

[Frosty.]

Looks like the AO index is about to go lower then it was back in the big freeze have a look here http://www.cpc.noaa....index_mrf.shtml

at the 14 AO day forcast its going to hit -5 to - 6

this supports the latest model output in regards to a cold spell hitting uk and ireland around the 8th of feb

And of course a cold spell before then hitting the uk from fri 29th jan through to early w/c 1st feb with a wintry weekend to come in many areas according to all the models.

Anyway, there is going to be a delay to the cold N'ly flow due to a shallow low moving southeast from iceland, as this slips across southwest scotland early on thursday, it will have the effect of temporarily weakening the strong NW'ly gradient across the north east of the uk. During the weekend, a low in the Norwegian sea, deepening due to the lee-effect of the Norwegian mountains, will slip south and give a significant wintry spell in the north and east during the weekend and start of next week.

[SMU]

UKMO at 120- Doing what I wanted to happen when I posted overnight-

Shortwave pumping the ridge ahead of it- 144 could be very good...

Steve

[Guest North Sea Snow Convection]

The 12z UKMO looks quite good.

That would evolve quite nicely I think

Edit: Beaten to it by the King!

Edited January 27, 2010 by North Sea Snow Convection

[nick sussex]

UKMO at 120- Doing what I wanted to happen when I posted overnight-

Shortwave pumping the ridge ahead of it- 144 could be very good...

Steve

Yes the 144hrs is very promising, seems to be the models continue to handle the eastern seaboard of the USA differently, the UKMO has a deeper low exiting over there. Shame the GME is so unreliable as that has the whole pattern further west and the best output so far. Looking at the models so far the deeper the shortwave the more that Atlantic trough gets held back, I think the GFS may have it too weak and hence the rather nerve shredding way to the easterly!

Edited January 27, 2010 by nick sussex

[andymusic]

Once again - GFS trend setter FI - amargeddon easterly! - beginning on the 8th Feb - a date very much repeated on this forum!

Edited January 27, 2010 by andymusic

[No Balls Like Snow Balls]

Once again - GFS trend setter FI - amargeddon easterly! - beginning on the 8th Feb - a date very much repeated on this forum!

Yep the Easterly keeps popping up in this time frame again and again. I definatley think there will be a Easterly, but whether it will be as cold as the GFS is makeing out I would say not.

[Geordiesnow]

Once again - GFS trend setter FI - amargeddon easterly! - beginning on the 8th Feb - a date very much repeated on this forum!

Its not really a trend setter though as the next run could very easily get rid of any easterly.

What is a trend setter is the height rises but will they affect us in any way or not is the question. I think some people were far too premature in there posts by congratulating people because they thought the easterly was all but nailed.

Could be some snowfall coming up for some but its a bit difficult to pin down where and who will get it at this stage. I still say Northern Scotland and perhaps eastern Scotland are the places to be if you want decent amounts of snowfall.

[sandstorm2]

The models are definitely trending cold, only worry is that with this forecasted easterly it is in the same timeframe as it was yesterday and this has happened time and time again.

It really should be moving into the +168 timeframe instead of staying at +260 and beyond.

SS2

[SP1986]

It does amuse me that people are hanging onto an easterly in FI which may or may not come off for the UK, it doesn't look particularly safe, however we do have a northerly in front of us with the potential for snow showers along eastern and western coasts and come frosty night to contend with.

Why bother with an easterly that is FI at best (whether or not its been shown for runs or not), and concentrate on the one thing we can be absolutely sure of, the northerly!

[andymusic]

It does amuse me that people are hanging onto an easterly in FI which may or may not come off for the UK, it doesn't look particularly safe, however we do have a northerly in front of us with the potential for snow showers along eastern and western coasts and come frosty night to contend with.

Why bother with an easterly that is FI at best (whether or not its been shown for runs or not), and concentrate on the one thing we can be absolutely sure of, the northerly!

Good point - but - as this is the model thread we here enjoy speculating over what's just over the hill that we can't quite see but would like to guess/work out/etc and right now the GFS keeps coming back to the 8th Feb with this screaming easterly and has been doing this for a few days now - it may well dissappear for a few runs but - call it a gut feeling - I think it'll be the form horse to back right now!

[NorthNorfolkWeather]

Why bother with an easterly that is FI at best (whether or not its been shown for runs or not), and concentrate on the one thing we can be absolutely sure of, the northerly!

yes Stephen, I agree.

The models look as though Friday through to Monday will be interesting to say the least, the frosts over the weekend could be very cold in sheltered parts of Scotland. Some of us in Eastern England may get quite a lot of the white stuff

[No Balls Like Snow Balls]

It does amuse me that people are hanging onto an easterly in FI which may or may not come off for the UK, it doesn't look particularly safe, however we do have a northerly in front of us with the potential for snow showers along eastern and western coasts and come frosty night to contend with.

Why bother with an easterly that is FI at best (whether or not its been shown for runs or not), and concentrate on the one thing we can be absolutely sure of, the northerly!

It may amuse you but the thing is the GFS must have spotted something, otherwise why would it keep appearing run after run!!.

[Rollo]

It does amuse me that people are hanging onto an easterly in FI which may or may not come off for the UK, it doesn't look particularly safe, however we do have a northerly in front of us with the potential for snow showers along eastern and western coasts and come frosty night to contend with.

Why bother with an easterly that is FI at best (whether or not its been shown for runs or not), and concentrate on the one thing we can be absolutely sure of, the northerly!

The problem with the Easterly is whether it is at 168 or 260 it is still in FI and so much can go still wrong,to get too excited at the moment will lead to having no finger nails left and god knows what else.

[Geordiesnow]

It does amuse me that people are hanging onto an easterly in FI which may or may not come off for the UK, it doesn't look particularly safe, however we do have a northerly in front of us with the potential for snow showers along eastern and western coasts and come frosty night to contend with.

Why bother with an easterly that is FI at best (whether or not its been shown for runs or not), and concentrate on the one thing we can be absolutely sure of, the northerly!

True but as people keep on saying, this is a model discussion thread so if people want to talk about an easterly in FI, then theres no harm in that. Aslong they don't give mis-leading posts like that the easterly is very likely to happen even though it is in FI.

Regarding the Northerly, as i say, northern and perhaps eastern Scotland would recieve the most snowfall but PPN charts suggest showers down western coasts in particular but it does look a little bit more marginal. There could be some prolonged snow for some inland areas but its too far out to pinpoint at this moment in time.

[nick sussex]

Until the models agree on events in eastern USA then we won't know what to expect downstream, alot rides on that pesky shortwave, if you want the quickest and safest route to the easterly with the least amount of drama then you want it to deepen as much as possible , this will force it to track more ne'wards and phase with the west Atlantic trough which will hold this further west and throw a stronger ridge ahead of it.

[NorthNorfolkWeather]

Good point - but - as this is the model thread we here enjoy speculating over what's just over the hill that we can't quite see but would like to guess/work out/etc and right now the GFS keeps coming back to the 8th Feb with this screaming easterly and has been doing this for a few days now - it may well dissappear for a few runs but - call it a gut feeling - I think it'll be the form horse to back right now!

I agree with you as well as Stephen, and it's a change not to have off putting @It's FI so it doesn't count' posts cropping up. I think FI should be looked at for trends rather than anything else

[The Weather Dragon]

Yes - focus on the Northerly this weekend - it looks certain & will definatley bring some wintery weather & some suprises. The Easterly is & has always been deep in FI and it may well stay there. I for one will not be taking notice until the Easterley scenario is getting within a 144/120 timframe and has general cross model agreement. Teleconnections can & have been overidden in the past.

[Snowaddict]

Major upgrade on the 12Z GEFS Ensemble suite..

In fact, there are a few members that support the GME/DWD 12Z Evolution, which is something akin to the ECMWF evolution of last night..

Mean 850mb Temperatures of -8 in London @ T+150..

Large & very positive turnaround when compared with the 06Z Ensembles..

[The Eagle]

GFS control run seems to be missing the middle of the script

156

GME at 132 is very like the ECM last night.

EDIT - you said exactly what I was going to say snowaddict. lol.

Edited January 27, 2010 by The Eagle

[SP1986]

I realise its a forum discussion and it can be talked about but just find really surprising that a northerly which does actually hold quite a bit of interest is being almost completely ignored for something we frankly cant be 100% sure will happen.

For me the northerly is interesting because even though it might not benefit those inland it will certain benefit those on western and eastern coasts, it's not just a northerly that would affect either the east or the west. I think there's a great deal of interest potentially in the northerly that being ignored for the easterly it seems.

[grab my graupel]

Folks, rather than complain about the missing posts in here, why not take a moment to think whether your post might have been better suited to an alternative thread?

The team doesn't move member's posts for fun - I can assure you. If you have any concerns about how the the forum is moderated, please feel free to pm a team member who will happily help to clarify things for you

Brian