314 replies to this topic

[Paul]

Oops, sorry about that got sidetracked between locking the old one and posting the new one. Anyway here it is - as ever discussion in this one and chat/banter in the other one, thanks!

[Steve Murr]

Afternoon All-

My first post of the day- I get the distinct 'underwhelmed' feeling on here & the other forums today which in the grand scheme of things in terms of how the models have changed at 120 in the last 2 days is slightly surprising-
Certainly the GFS ensembles have gone from NO amplification 2 days ago, to a running mean past the 20th yesterday 12z at around -2c 850 HPA to this Morning a running mean of -5c & the overall trend along the line out to the 23rd is lower still-
As some of us have said the modelling & evolution podt 120 is not going to be easy but we SHOULD get some good clarity over the next 24 hours-
Even the Nogaps is Very solid on its ensembles-
http://176.31.229.22...0&ville=Londres

In this fickle model period I would run ODDS on 60/40 ( so just favourite) that we do get a deeper second drop on the outlook ( especially for England) to down around -8c for the 23rd in the ensemble mean tonight
& I would again go 60/40 odds on that we see an easterly within 8 days - ( an easterly or a continental South easterly which sometimes can be warmer at 850 level but just as cold at the surface & with more snow...

best regards
Steve

[Weather wizard]

The low looking quite a bit stronger on the 12z over Iceland at 36h

[shedhead]

Admittedly it's early doors, but looking at the T+48hr it's hard to see this run turning out much different to it's predecessor, with little in the way of widespread cold likely to develop inside the higher res section.

[Weather wizard]

shedhead, on 16 January 2012 - 16:04 , said:

Admittedly it's early doors, but looking at the T+48hr it's hard to see this run turning out much different to it's predecessor, with little in the way of widespread cold likely to develop inside the higher res section.

I am not sure how you can make such a sweeping statment so early on in a run

Huge changes at just T+90 on GFS look how much deeper the low is to our north

However these changes produce an even worse run than the 06z

Edited by Weather wizard, 16 January 2012 - 16:12 .

[Matty M]

Well if people were expecting the 12z GFS to suddenly come good in the short-medium term they look like being disappointed this evening.

GFS Operational staying steady enough out to T102hrs with little sign of much cold air.

But i am looking at the later part of the run for interest, towards T144hr to see if we can get a second
shot at building a ridge to Greenland

Edited by Matty M, 16 January 2012 - 16:14 .

[KTtom]

shedhead, on 16 January 2012 - 16:04 , said:

Admittedly it's early doors, but looking at the T+48hr it's hard to see this run turning out much different to it's predecessor, with little in the way of widespread cold likely to develop inside the higher res section.

If you can have a downgrade this early on then this is it..nowhere in the UK sub -5 mid-day Friday.

http://www.wetterzen...cs/Rtavn962.png

[shedhead]

Weather wizard, on 16 January 2012 - 16:07 , said:

I am not sure how you can make such a sweeping statment so early on in a run

Huge changes at just T+90 on GFS look how much deeper the low is to our north

Yes it is much deeper, but what are you suggesting might be the likely implications of this further into the high res part of the run?

[Weather wizard]

shedhead, on 16 January 2012 - 16:12 , said:

Yes it is much deeper, but what are you suggesting might be the likely implications of this further into the high res part of the run?

I am saying that since there is so much uncertainty due to the lack of continuity between runs so early on,
the rest of the output will also be subject to large uncertainty.

[Steve Murr]

Hum not a lot of Accuracy so far in this thread-

GFS much more akin to UKMO now-
http://modeles.meteo...12-0-114.png?12

UKMO good at 96 as well-
http://www.meteociel...96-21.GIF?16-17

ALSO very good UKMO 120
http://www.meteociel...20-21.GIF?16-17

GFS 126
http://modeles.meteo...12-0-126.png?12

WALL of cold building up to the NE & the atlantic low seperated from a smaller shortwave on its southern flank which is good-

S

[Zakos]

Weather wizard, on 16 January 2012 - 16:16 , said:

I am saying that since there is so much uncertainty due to the lack of continuity between runs so early on,
the rest of the output will also be subject to large uncertainty.

yes look at 117 hours, huge difference to 06z, consitentcy at an all time low....

[shedhead]

Weather wizard, on 16 January 2012 - 16:16 , said:

I am saying that since there is so much uncertainty due to the lack of continuity between runs so early on,
the rest of the output will also be subject to large uncertainty.

The kind of differences shown are not that unusual when talking about the certral pressure of Lows to our north in January, even in the 48-72hr timeframe. Apart from that it has to be said there
is not much lack of continuity between the 06 and the 12GFS, in fact the continuity overall out to T+120hrs is actually rather good.

[Weather wizard]

Steve Murr, on 16 January 2012 - 16:18 , said:

Hum not a lot of Accuracy so far in this thread-

GFS much more akin to UKMO now-
http://modeles.meteo...12-0-114.png?12

UKMO good at 96 as well-
http://www.meteociel...96-21.GIF?16-17

ALSO very good UKMO 120
http://www.meteociel...20-21.GIF?16-17

GFS 126
http://modeles.meteo...12-0-126.png?12

WALL of cold building up to the NE & the atlantic low seperated from a smaller shortwave on its southern flank which is good-

S

Yes the low in the atlantic is better placed but the original low on Friday is significantly worse.

[Steve Murr]

http://modeles.meteo...12-0-132.png?12

COMON THE FLOODGATES OPEN DAM IT... another 18 hours & I think it will be there-
S

[Matty M]

I think after repeated attempts at a ridge we will get a pay day around 23rd Jan

Decent agreement between the UKM and GFS at 120hrs tonight.

[nick sussex]

The chaos continues with both the GFS and UKMO disagreeing at 144hrs.

Interestingly on the UKMO the PV has decided to leave the scene but overall I suspect we're going to be no nearer knowing whats likely to happen for some time to come.

Really quite unbelievable that the models just can't seem to cope with anything past 120hrs at the moment.

[KTtom]

http://www.wetterzen...s/Rtavn1501.png

Its almost a race between the approaching Russian high to the east and the Atlantic systems to the NW to see has control of the UK. Looks to me like the Atlantic is a little faster on its heels for this run.

[Matty M]

That shortwave south of Greenland needs to dive southeastwards over us i feel and allow another attempt at ridging to greenland, because it could just waste days of winter where it is progged on the UKM and GFS

[Zakos]

nick sussex, on 16 January 2012 - 16:28 , said:

The chaos continues with both the GFS and UKMO disagreeing at 144hrs.

Interestingly on the UKMO the PV has decided to leave the scene but overall I suspect we're going to be no nearer knowing whats likely to happen for some time to come.

Really quite unbelievable that the models just can't seem to cope with anything past 120hrs at the moment.

Yes i agree. This, to me suggests a major pattern change is underway, and the models simply dont know what to do.

After all, they are only computer programs, and all though they can accurately predict the path of lows etc..

when it comes to rapidly rising heights in the Arctic, the models dont know what do, because let face it, no one really knows exactly why high pressure forms.

[happy days]

Its all very frustrating isn't it.We seem to be having numerous bites at the cherry regarding the anticyclone to the NE but the Atlantic just keeps shutting the door on us.
At least there is no sign of that jet blasting into scandy but the PV needs to back west and we need to see some energy dive to the SW of the UK to allow the high to drag the cold west.