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

[Cheshire Freeze]

are these more reliable in the time frame you are talking about or is it still to be considered FI??

Very much FI but given what I've heard about the EC32 day and the hints from the Metoffice regarding potential Feb cold plus having looked at stratospheric signals (warming centred over Greenland within the 7 day timeframe) I think a cold spell in Feb is favoured. I believe GP is banging this drum aswell.

All very tentative at the moment though and open to change.

I also wonder whether the spell we're having is the initial response to the warming of the strat with a more pronounced and obvious blocking episode around the corner, 4 weeks after the warming started.

Edited January 21, 2013 by CreweCold

[matty lfc]

Can someone please explain If im on the right tracks here.If the angle of attack from the lows are more nw to se,does that take the energy further south allowing cold air from the north and east to influence our weather?

Is the angle of attack critical to UK weather?

Thanks for any help.

[Jason M]

GFS ensembles if anything tend to favour high pressure building up from the south via the AZH. Typical Feb fare really with more blocking about but generally in all the wrong places.

No point in taking particularly seriously though at long range. An undercutting scenario at weekend has a little support here and there which is a big improvement on the zero support this morning. It still all looks fairly inevitable though as despite the charts in isolation looking primed for big height rises over Scandi, it just doesnt happen for some reason.

With the PV floating around in mid atlantic the danger is that we see an iberian / AZH pressure rise in response.

Its odd, but this winter the background signals seem strongly against heights to our north. This has been a really good cold spell courtesy of the SSW, but it still looks like its on its way out at present.

Jason

[london-snow]

Okay this is my punt for the outlook.

I think we may well see a snowy breakdown towards sat evening.

Although temps seem to rise after the weekend i don't think it will get that mild with the colder weather holding out the further north & east you go with showers into southern most countys.

Into the later part of next week i think the cold may try to creep back in from the east however lp systems will prevent this & need to watch for possible flooding into south western areas. Cold never to far away though.

I'm looking at the period say 2nd ~ 5th of next month when i feel the chance of a prolonged & very cold spell of weather to come from the north east. I feel that it will be a lot worse than the spell we are currently in infact on par or better than 2010.

[Jason M]

Can someone please explain If im on the right tracks here.If the angle of attack from the lows are more nw to se,does that take the energy further south allowing cold air from the north and east to influence our weather?

Is the angle of attack critical to UK weather?

Thanks for any help.

Yes re your first question.

In relation to your second question not neccersarily, but strongly yes in the current set up.

Jason

[Cheshire Freeze]

Okay this is my punt for the outlook.

I'm looking at the period say 2nd ~ 5th of next month when i feel the chance of a prolonged & very cold spell of weather to come from the north east. I feel that it will be a lot worse than the spell we are currently in infact on par or better than 2010.

I think you may well be spot on in your timings sir!

Strength, duration etc impossible to speculate over at this time but I would suggest a plunge from the NE sometime between 3-7th Feb

[matty lfc]

Yes re your first question.

In relation to your second question not neccersarily, but strongly yes in the current set up.

Jason

Thanks,much appreciated

[Snowmad79]

Yes and even though the BBC are now mentioning milder by the weekend the UKMO update suggests snow for the east and south as that happens.

So certainly you'd have to have some trough disruption for that, the UKMO hints at that, the GFS 06hrs goes for it , the ECM doesn't although NOAA think it might be too quick to eject energy eastwards out of Canada as the PV breaks down.

Looking at the UKMO 96hrs:

I'd say snow prospects for the weekend will be increased if the models develop that shortwave out of the ne USA more, circled red, if they also amplify that more this will help pull back the energy nw near Iceland and sharpen the approach to eject that shortwave near Iceland circled black se further west.

I think eventually even with that the odds strongly favour milder conditions next week but lets see if we can squeeze out a bit more snow before that happens!

The odds do strongly favor milder conditions. But only if you believe output post 72hr. I did exactly that other week, backing an Atlantic surge and was left feeling a right t*t when the tiny wedge of HP won out.

Only problem with that thinking is that the Stat doesn't support any wedge of HP to our N/NE holding out ?

[london-snow]

I think you may well be spot on in your timings sir!

Strength, duration etc impossible to speculate over at this time but I would suggest a plunge from the NE sometime between 3-7th Feb

Thanks CC.

Agreed it is impossible to predict in advance in terms of how long a pattern can hold. Though i do see a big shift south in regards to the jet hence keeping the atlantic at bay & hence increase in the prolonged punt.

We will find out soon enough & considering we have another five days of cold weather which takes us up to the 26th for those who are enjoying this event & staying away from the mod thread it could be a big shock when this current spell is over and they come back on here and see a 2010 re run in medium outlook.

[Cheshire Freeze]

Thanks CC.

Agreed it is impossible to predict in advance in terms of how long a pattern can hold. Though i do see a big shift south in regards to the jet hence keeping the atlantic at bay & hence increase in the prolonged punt.

We will find out soon enough & considering we have another five days of cold weather which takes us up to the 26th for those who are enjoying this event & staying away from the mod thread it could be a big shock when this current spell is over and they come back on here and see a 2010 re run in medium outlook.

Caveats apply though. At this range there are a plethora of obstacles which could stand in our way, not least the MJO which may refuse to play ball. Though GP's bullishness reassures me on this. Head for MJO stage 8 for Feb and we won't go far wrong

[london-snow]

Caveats apply though. At this range there are a plethora of obstacles which could stand in our way, not least the MJO which may refuse to play ball. Though GP's bullishness reassures me on this. Head for MJO stage 8 for Feb and we won't go far wrong

You really do have to give it up for GP after saying back in dec the main event looks to be the start of feb & is still backing it today.

Not only GP but RJS & BFTP all great but above all explains the reasoning behind why they feel that Feb 2013 could be a month that will go down in history.

[weather eater]

Whats going on here because this is very different.

http://modeles.meteo...gfs-0-114.png?6

Rather late on this as I've been busy, but that's what I thought

[phil nw.]

Interesting to see the change in the fax`s for T84-compared to T96hrs that Cloud 10 posted above.

It shows the energy from Canada just a little weaker with those approaching lows held back a little by the block.

I noticed on yesterdays 12z GFS a reluctance at T144hrs- as it was then- to push the Atlantic in but it did evolve that way in later frames-so maybe a delay and the surface cold taking longer to mix out perhaps.

However looking at the ens 2mts temps a warming trend is there from the weekend.

It may well be that some of the operational runs are going too mild with the pattern and looking at the blue line(GFS)on that graph suggests this

.

As for that hint of cold returning in February well some signs in the index graphs from the 00z Ens.outputs here of a dip in the NAO and AO to negative around day 15 -some time away so let`s see if this continues to be a growing sign in future runs.

Here`s the 00z GFS mean hts anomls. for that period.

which supports Greenland hts modeled in recent operationals.

Edited January 21, 2013 by phil n.warks.

[Tim Bland]

12Z NAE has pushed the event for tommorow in the SW further east. Could mean central southern England IE Bucks / South Mids get the snow and further SW is more margingal ?!

http://www.weatheron...S=0&WMO==

[Frosty.]

Today's latest meto update is encouraging, for a start, it indicates that saturday will still be cold with sleet and snow at least across central and eastern areas with trough disruption across the uk but by sunday we are pretty much all in the same boat with temps recovering towards average with spells of wet and windy weather, into next week, a milder theme but remaining unsettled but temps then beginning to trend lower with the chance of snow returning to northern hills at least, it actually sounded very similar to the Gfs 06z op run although i'm sure that's just coincidence, the 6z shows early mild but then trending a little colder as the jet begins to tilt more nw/se and we begin to see an increase in polar maritime type incursions post T+200 hours, this increases even more beyond T+300. The 6z is very much work in progress because we are looking for strong heights rises around greenland/iceland but it seems a good template to represent what the meto are indicating because that trend towards a return of the current icy/snowy conditions is again in the further outlook so the milder pattern beyond the weekend may only be fairly brief before we gradually return to the freezer between early and mid feb.

[simon29]

The huge low that is shown in the atlantic, would it ever be possible to have one that deep coming from the east in winter, or is only the west because of the moisture over the atlantic

[shotski]

If it ever does I'm on the first plane out off here

[nodrog]

The huge low that is shown in the atlantic, would it ever be possible to have one that deep coming from the east in winter, or is only the west because of the moisture over the atlantic

Not really. You can get deep lows winding up as they move over - think a few years ago one (1/4 the size) moved down the East Coast thus raised flooding alerts ect. But in general it would be a rare event. Unless im wrong im sure someone on here will correct me.

[bluearmy]

The huge low that is shown in the atlantic, would it ever be possible to have one that deep coming from the east in winter, or is only the west because of the moisture over the atlantic

correct simon. that and other factors such as upper temp gradient and SST's. you could not have a system approach from the east that size and depth.

[Cloud 10]

GFS 12z at 72 hrs has backed things west which means -8 uppers back into eastern England.

edit. the UKMO trumps it at the same timescale.

Edited January 21, 2013 by Cloud 10

[Summer Sun]

GFS 12z at 72 hrs has backed things west which means -8 uppers back into eastern England.

edit. the UKMO trumps it at the same timescale.

Milder air trying to move in from the west at t90

Edited January 21, 2013 by Gavin.

[Anti-Mild]

Out to +78 on the 12z GFS and on the 6z it had the -5 850hPa isotherm running parallel to the east coast, on the 12z it's up the west coast. Slightly better heights to the NE as well. Looks like another slight delay on the milder stuff!

The UKMO is out to +72 and also looks to be a slight improvement on the 0z.

As many of our experts have said, it's proving very difficult for the Atlantic to shift the cold block - I expect further delays on the breakdown.

[Swave Snow]

Snow Battle could be on the cards again for large parts of the UK, so hard to predict

[MR EXTREMES]

corr blimey look at them cold uppers to our east thats a coldies dream steve murr would love it over there he would build the biggest ramp in the world and i would not be far behind.

i think gp could be right give it awhile and if that cold air can stay over there then we could be in for a suprise in febuary.

[MR EXTREMES]

ukmo at t72 cold uppers across most of the uk nice to see slowly the breakdown is coming.

to be honest it wouldnt be all that bad if azores ridged ne over us.