Winter Model Discussion 18Z 19/1/13 onwards.

[bsnowy]

Out of interest is there any evidence to suggest we are experiencing less northerly events and more easterly events. It must be several years since the last major northerly.

[Frosty.]

It could be right Frosty, remember how the PV lobe moved out of Canada in December. We could be looking at something similar happening now.

Yes it could be a return to the pony winter pre cold snap, hope not though. Still a lot of uncertainty from friday onwards.

[BLAST FROM THE PAST]

Agreed. I too sense that GP is holding off posting until pressure rises to the NW and the siberian lobe backs west... and the longer he stays quiet the more concerned I become. If December hadnt so massively under modelled the amount of energy dropping out of Canada I wouldnt be so bothered: as it is everyone I think was caught out by the amount of energy that the "flick of the tail" sent towards us back then, enough to completely destroy 2 weeks of weather (unless you l like cold rain of course)

But it hasn't prevented this cold spell though has it? GP posting or not cannot change or determine whats going to happen, so I wouldn't be too perturbed or read anything into him not posting and to be honest I don't think his GHP period has arrived yet?. We still have eleven days of Jan, I personally have suggested the GHP/Arctic HP to strengthen and influence more after my 16-22 period, the 120 fax chart really made me sit up.

BFTP

Edited January 20, 2013 by BLAST FROM THE PAST

[billy]

have you moved to the uk from canada ? this winter, based on the past few decades is pretty reasonable re cold and snow thus far. not near the top but a long way from the bottom. we still have 5 to 6 weeks before march so methinks your post is a tad early.

Indeed, seven days in a row of lying snow (and counting) , two nights of double digit minus figures, barely above 0 degrees for seven days now , and im seven miles from the coast at sea level. Ive seen worse here believe me

[Tom D]

http://www.meteociel.fr/modeles/gefs_cartes.php?code=21&ech=144&mode=0&carte=

06z ensembles are IMO very good. About half of the 20 peturbations send the energy SE at or around t+144. There are 3 or 4 others that are not far from doing the same, and then the remaining 6 or 7 show the kind of Atlantic breakthrough that both the operational and control and indeed the ops of both the UKMO and ECM show at around +144.

Peturbations 2, 3, 6, 9, 10, 15, 18 and 20 are all great or close to being so.

The mean, linked above, doesn't really justify any comments that the cold spell is definitely going to end either. I may end up eating my words later...

[The Weather Dragon]

Out of interest is there any evidence to suggest we are experiencing less northerly events and more easterly events. It must be several years since the last major northerly.

Last major northerly was nov/dec 2010

[Jason M]

http://www.meteociel.fr/modeles/gefs_cartes.php?code=21&ech=144&mode=0&carte=

06z ensembles are IMO very good. About half of the 20 peturbations send the energy SE at or around t+144. There are 3 or 4 others that are not far from doing the same, and then the remaining 6 or 7 show the kind of Atlantic breakthrough that both the operational and control and indeed the ops of both the UKMO and ECM show at around +144.

Peturbations 2, 3, 6, 9, 10, 15, 18 and 20 are all great or close to being so.

The mean, linked above, doesn't really justify any comments that the cold spell is definitely going to end either. I may end up eating my words later...

Yes, just thinking that. Very strange at the moment as when I ran through them at 126 it looked like a nailed on breakdown. Then 24 hours later many of them change again. A couple with sneaky Greeny highs I noticed.

Jason

[The Weather Dragon]

http://www.meteociel.fr/modeles/gefs_cartes.php?code=21&ech=144&mode=0&carte=

06z ensembles are IMO very good. About half of the 20 peturbations send the energy SE at or around t+144. There are 3 or 4 others that are not far from doing the same, and then the remaining 6 or 7 show the kind of Atlantic breakthrough that both the operational and control and indeed the ops of both the UKMO and ECM show at around +144.

Peturbations 2, 3, 6, 9, 10, 15, 18 and 20 are all great or close to being so.

The mean, linked above, doesn't really justify any comments that the cold spell is definitely going to end either. I may end up eating my words later...

Maybe the GEM op is onto something with energy diverted SE. This has been a stubborn block much stronger than any of us thought it would be.

[Frosty.]

The GEFS and ECM 00z ens mean show the atlantic system sweeping into the uk by T+144 onwards with a relatively milder and unsettled pattern taking hold of our weather by next weekend.

[Gibby]

It has nothing to do do with Global Warming. The way the weather set up in 1963 would be the same today if we had the same blocking as then.

I agree to a point but believers would say that its because of global warming that would prevent such synoptics to form and last so long that would make such a reoccurrence unlikely.

Anyway OT I think that any breakdown next weekend is going to be slow and arduous with further delays to the ingress from the Atlantic on the 12zs, or that's my hunch.

[Jason M]

The GEFS and ECM 00z ens mean show the atlantic system sweeping into the uk by T+144 onwards with a relatively milder and unsettled pattern taking hold of our weather by next weekend.

Hi Frosty

Not sure the mean is very useful here. Subtle differences mean big differences for us. In broad terms you can't argue with the mean, but i still think is too far west.

Jason

[Frosty.]

Hi Frosty

Not sure the mean is very useful here. Subtle differences mean big differences for us. In broad terms you can't argue with the mean, but i still think is too far west.

Jason

too far west? i'm hoping, an i'm sure most others are hoping the cold block can last longer but the angle of attack being more west to east makes it much easier for the deep depression to force it's way into the uk and mix out the cold uppers.

[TEITS]

, I personally have suggested the GHP/Arctic HP to strengthen and influence more after my 16-22 period, the 120 fax chart really made me sit up.

BFTP

Trouble is though Fred none of the models indicate a GH or indeed a Arctic HP to influence our weather in the near future. Our best hope of a continuation of the cold spell is to see continued energy going SE. At the moment this doesn't seem likely and a return to mild is the most likely outlook, at the moment!

What I am certain of though is any form of cold weather is more likely from the east. A N,ly via a Greenland HP is extremely unlikely.

[Jaffusmaximus]

Trouble is though Fred none of the models indicate a GH or indeed a Arctic HP to influence our weather in the near future. Our best hope of a continuation of the cold spell is to see continued energy going SE. At the moment this doesn't seem likely and a return to mild is the most likely outlook, at the moment!

What I am certain of though is any form of cold weather is more likely from the east. A N,ly via a Greenland HP is extremely unlikely.

I know its in FI but the GEM has developed this earlier.

[TheBigFreeze]

do the models use historic data about the way certain fronts / systems / interact with others when predicting what will happen or was that all programmed in at the start of the models programming??? sorry if in wrong thread mods

[bluearmy]

the way i read the updated ukmo 30 dayer (wording changed a bit), it seems that the ecm 32 dayer plus advice from the strat people leads them to suspect blocking to our nw is the likely result by mid feb. reading ed's thoughts it maybe that a mobile period is assured whilst that canadian energy jeads across the atlantic. if we want the cold to continue, we either need to hope that either the canadian vortex retains energy and doesnt dissipate (may well prohibit a feb greeny block) or that an azores ridge running ahead of the energy this week builds north and rebuilds the weak blocking to our north and we see a repeat of what we currently have with the energy running to our sw. (similar to gem).

there are more and more very amplified gefs runs in week 2 showing up, only a few manage to keep us cold but there are plenty of decent scandi and greeny blocks showing up.

[Paul T]

Oh dear, Breakdown pretty much nailed for next Saturday on GFS and ECM. Can't see where any rescue would come from now.

The ensembles are almost all suggesting the same "warm up" in 850's, this wasn't the case with previous breakdown suggestions.

We are 2-0 with five minutes to play...it's not lookin good.

On a brighter note, some fun Synoptics today and early next week expected with potential snow likely to pop up almost anywhere. Mustn't grumble on that basis.

[Robbie Garrett]

Did you watch that 1963 documentary last night?

Atlantic may make inroads slightly, but I can't see it being full blown zonal. We need that vortex chunk over newfoundland to dissipate and then some true northern blocking will come into place.

You only have to look at the mean pressure charts of ECM and GFS and they suggest a breakdown. The argument of that they are overplaying the Atlantic is a fair one but the problem is that the ensembles ain't budging infact they are firming up on the idea. It looks a breakdown from the continental airmass to a less cold polar maritime airmass.

It's hard not to ignore it.

[reef]

The GFS 06z is actually quite a substantial upgrade this week in the strength of the cold. This time yesterday we were looking at a probable wintry mix at low levels in any precipitation this week as 850hPa temperatures were very marginal indeed. Now it seems that they remain below -5C for much of the country pretty much until next Saturday. Indeed, on Tuesday/Wednesday the low pressure is now considerably further south than forecast, keeping the colder air in play. Heres Wednesday over the UK for example:

As this system then pulls away we get some very cold temperatures over the following nights:

The models seem to agree on a breakdown on Saturday to less cold weather from the west, but this is still 6 days out so needs to be taken with a huge pinch of salt, especially as the models are not in agreement how it is going to happen.

Edited January 20, 2013 by reef

[johnholmes]

do the models use historic data about the way certain fronts / systems / interact with others when predicting what will happen or was that all programmed in at the start of the models programming??? sorry if in wrong thread mods

answered a similar one earlier-no, simply take the current weather from the surface way into the Stratosphere (for most models) and the models then number crunch

[Methuselah]

Can anyone recall what this thread's is meant to be about?

[johnholmes]

Can anyone recall what this thread's is meant to be about?

vaguely to do with what the models may be showing currently but then diversions do occur!

[weatherguy]

I think it's going to stay cold after next week because I saw a pigeon sit on a branch of a tree that had no pigeons on it last week!

The above is about as reliable as the information that the models give us after T+96, and is perhaps why the analysis has been somewhat lacking recently

[mike Meehan]

I think it's going to stay cold after next week because I saw a pigeon sit on a branch of a tree that had no pigeons on it last week!

The above is about as reliable as the information that the models give us after T+96, and is perhaps why the analysis has been somewhat lacking recently

So what does this mean?

Edited January 20, 2013 by mike Meehan

[mike Meehan]

Can anyone recall what this thread's is meant to be about?

er, pass, ask me another