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Paul

Model Discussion - 16th January

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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!

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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://176.31.229.228/modeles/gens/nogaps/graphe_ens3.php?x=306&y=141&run=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

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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.

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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

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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 :)

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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.wetterzentrale.de/pics/Rtavn962.png

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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?

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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.

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

GFS much more akin to UKMO now-

http://modeles.meteociel.fr/modeles/gfs/runs/gfsnh-2012011612-0-114.png?12

UKMO good at 96 as well-

http://www.meteociel.fr/ukmo/runs/2012011612/UN96-21.GIF?16-17

ALSO very good UKMO 120

http://www.meteociel.fr/ukmo/runs/2012011612/UN120-21.GIF?16-17

GFS 126

http://modeles.meteociel.fr/modeles/gfs/runs/gfsnh-2012011612-0-126.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

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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....

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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.

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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.

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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.

UW120-21.GIF?16-17

gfs-2012011612-0-120.png?12

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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.

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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

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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.

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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.

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Another close but no cigar situation from the 12z again. At around t140 I thought the floodgates might open from the east, but the atlantic is just to stubborn. Perhaps we'l see it budge later on the 18z. Big, Big ECM coming up.

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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

You took the words right out of my mouth steve, with the low track much more NW-SE a bit more amplicfication too.

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The GFS 12z flirts, but does not want the UK to have anything to do with the East. I am still of the opinion that the models cannot handle major synoptic change and will fight against influence from the East until the change is on top of us. The ensembles will be interesting but I doubt they will give us any definite clues. I think it will be on like Kong before too long.

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Maybe a lot of snow for ne scotland if the ukmo 12z verified? trough close to ne britain and a NE'ly element to the windflow from a very cold source, maybe some snow showers down the eastern half of the uk on saturday? It doesn't look wintry for western britain but there is a chance for the east and northeast, I can't imagine the pattern will be pushed any further west, more chance of being shunted east.

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GFS is edging towards a snowfest for england > the midlands +NE/ E/SE at 192-

Doesnt look all that great in the big picture but when you see this-

http://www.wetterzentrale.de/pics/Rmgfs1892.gif Uppers -2

http://www.wetterzentrale.de/pics/Rmgfs1899.gif Theta Around 10-12C

http://www.wetterzentrale.de/pics/Rmgfs1898.gif Surface dewpoints -2c

http://www.wetterzentrale.de/pics/Rmgfs1894.gif Surface temps Zero & below

http://www.wetterzentrale.de/pics/Rmgfs1893.gif PPN moving slow east...

The GFS is NEARLY NEARLY there & UKMO looks good-

Very positive this eve-

S

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